05-01-2007, 03:15 AM
1) A 24-year-old dress designer complains of a crampy periumbilical pain. These symptoms have been present over the past 9 months since she began her first job after graduating art school. During that time, she has had several episodes of constipation lasting 4-5 days. These are typically followed by 3-4 days of frequent loose bowel movements. She denies any bloody stools, fever, weight loss, or change in appetite. Her symptoms are generally milder on weekends. Her physical examination is normal. Her white blood cell count is 6700/mm3, her hematocrit is 38%, and her erythrocyte sedimentation rate is 4 mm/h. Her serum albumin and liver function tests are normal. Which of the following is the most likely diagnosis?
A. Crohn disease
B. Diverticulosis
C. Giardia infection
D. Irritable bowel syndrome
E. Ulcerative colitis
Explanation:
The correct answer is
D. This patient has typical crampy abdominal symptoms with alternating diarrhea and constipation. She is a young individual with chronic symptoms, which is very typical of irritable bowel syndrome. Patients with this diagnosis will generally have symptoms of pain related to meals or stress and an alteration in bowel habits. This change in bowel pattern may take the form of frequent loose stools versus constipation, or a combination of both. These patients have no physical findings or laboratory results to suggest an inflammatory process. Dietary changes and stress reduction are usually the goals of therapy, with antispasmodic drug therapy for symptomatic relief.
Crohn disease (choice A) is associated with a number of inflammatory findings, including tenderness on abdominal examination, mucopurulent or bloody stools, weight loss, and/or leukocytosis, and/or elevated erythrocyte sedimentation rate (ESR).
Diverticulosis (choice B) rarely happens in patients this young and will typically present with constipation without diarrheal symptoms.
Giardia infection (choice C) may cause chronic symptoms with abdominal cramping, but typically with symptoms of upper gastrointestinal involvement, such as nausea, vomiting, and eructations, since Giardia tends to live in the upper small bowel.
Ulcerative colitis (choice E) will present with bloody stools and evidence of an inflammatory condition, e.g., elevated ESR.
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2) A 34-year-old tax lawyer presents to his physician complaining of difficulty swallowing. On several occasions over the past few months, he was aware of meat becoming stuck in his mid-chest immediately after eating. After each episode, he had several hours of chest pain, which gradually resolved. On two occasions, he induced vomiting to obtain relief. Over the past 10 days, the swallowing difficulty has become worse, and he now has trouble with even soft foods and is limiting himself to pureed food. He has been taking ranitidine, magnesium hydroxide, and omeprazole for 4 years, but has remained symptomatic despite these measures. He has been smoking one pack of cigarettes daily for 15 years and denies any alcohol use. The physical examination is normal. Which of the following is the most likely explanation for these symptoms?
A. Diffuse esophageal spasm
B. Esophageal squamous carcinoma
C. Lower esophageal web
D. Peptic esophageal stricture
E. Scleroderma
Explanation:
The correct answer is
D. This patient presents with symptoms consistent with gradual luminal narrowing of the esophagus after many years of gastroesophageal reflux disease (GERD). These symptoms suggest the development of a benign peptic stricture. This may occur even if the patient is on medical therapy to reduce acid secretion, since many patients will continue to produce acid despite standard medical regimens and may require very high doses of proton pump inhibitors. Treatment consists of endoscopic dilation of this stricture and continued aggressive anti-reflux therapy.
Diffuse esophageal spasm (choice A) presents with "noncardiac chest pain," usually described as a mid-chest(squeezing chest pain. It typically presents with a motility-type dysphagia. Although GERD is a common underlying factor, the type of dysphagia in esophageal spasm would be consistent with a motility-type dysphagia, i.e., patient has difficulty with liquids as well as solids from the onset of his symptoms.
Squamous carcinoma (choice B) is not a sequelae of longstanding GER
D. Furthermore, his age makes it extremely unlikely that he would develop esophageal carcinoma (even with his history of smoking as a risk factor).
A lower esophageal web (choice C) or Schatzki ring produces dysphagia in an episodic pattern as foods that are greater in size than the diameter of the web, become lodged in the distal esophagus.
Scleroderma (choice E) could cause dysphagia, but this would be accompanied by Raynaud's phenomenon and characteristic changes in the skin. Additionally, scleroderma is about three times as common in women than in men.
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3) A 39-year-old man comes to medical attention because of a 1-year history of personality changes, abnormal involuntary movements, and memory dysfunction. His father and grandfather died in their 50s because of progressive mental deterioration accompanied by movement abnormalities. The patient is married but has no children. Neurologic examination and psychometric testing reveal difficulty in concentration, mild depression, and marked restlessness. During the examination, grimacing of the face and intermittent shrugging of the shoulders are noted. MRI examination of the brain reveals hyperintensity in the region of the caudate on T2-weighted images. Which of the following is the most likely diagnosis?
A. Creutzfeldt-Jakob disease
B. Gilles de la Tourette syndrome
C. Huntington disease
D. Sydenham chorea
E. Tardive dyskinesia
Explanation:
The correct answer is
C. The clinical manifestations and family history are consistent with Huntington disease. This autosomal dominant condition is caused by an unstable expansion of a CAG trinucleotide repeat in a gene encoding a novel protein named huntingtin. The age of clinical onset is commonly between 30 and 50 years, but may be as early as 5 years. Behavioral abnormalities and personality changes often precede the characteristic choreiform movements. Irritability, restlessness, and difficulty in concentration are among the most frequent early clinical manifestations. The pathologic substrate of this condition is degeneration of the striatal neurons, especially those in the caudate nucleus. Caudate nucleus changes may be appreciated on MRI examination or PET scans.
Creutzfeldt-Jacob disease (choice A) is characterized by rapidly progressive dementia associated with myoclonic movements. The disorder is familial in 10% to 15% of cases. It is probably caused by spontaneous mutations of the gene coding for prion protein.
The onset of Gilles de la Tourette syndrome (choice B) is usually between 2 and 15 years of age. Motor or phonic tics are the principal manifestations, including sniffing, blinking, spitting, grunts, coughs, and coprolalia.
Sydenham chorea (choice D) is one of the major Jones criteria for the diagnosis of rheumatic disease.
Tardive dyskinesia (choice E) is a late complication of antipsychotic drugs that block dopamine D2 receptors. It most commonly manifests with persistent chewing movements and intermittent protrusion of the tongue.
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4) A 64-year-old woman presents to her physician for management of her hypertension, which has been treated unsuccessfully for several years. She was recently hospitalized for pulmonary edema, and an echocardiogram at that time showed a moderately depressed ejection fraction. She was diagnosed with congestive heart failure. Her medications include a thiazide diuretic and a calcium channel blocker. She has an allergy to furosemide. Her review of systems is positive for two-pillow orthopnea and occasional paroxysmal nocturnal dyspnea. On physical examination, her blood pressure is 150/80 mm Hg, and her pulse is 80/min and regular. Her lungs are clear, and there are no extra heart sounds. Her extremities are without edema. Which of the following is the most appropriate management at this time?
A. Add an ACE inhibitor to her regimen
B. Add an angiotensin II receptor blocking agent to her regimen
C. Add hydralazine to her regimen
D. Increase the dose of her calcium channel blocker
E. Increase the dose of her thiazide diuretic
Explanation:
The correct answer is
A. This patient has both hypertension and congestive heart failure (CHF). An important concept to recognize in the treatment of medical conditions is that certain medications overlap syndromes and are efficacious in many areas. This "co-treatment" option maximizes each drug in a regimen and often addresses two or more issues simultaneously. In this case, ACE inhibitors have been shown to be very beneficial in prolonging the survival of CHF patients.
Adding an angiotensin II receptor blocking agent to a regimen (choice B) has become an alternative for ACE inhibitor therapy in patients who cannot tolerate these drugs for a variety of reasons. Although their efficacy in lowering blood pressure appears to be equivalent to that of ACE inhibitors, no data have shown their survival benefit to be similar to ACE inhibitors. Because such a clear mortality benefit has been demonstrated for ACE inhibitors, a compelling reason exists to use them preferentially in almost all patients with systolic dysfunction.
Adding hydralazine to her regimen (choice C) would certainly help to treat her blood pressure but will do nothing in terms of helping her CH
F.
Increasing the dose of her calcium channel blocker (choice D) or her thiazide diuretic (choice E) would most certainly aid in lowering her blood pressure, but neither of these medications has any significant utility for treating either systolic or diastolic CH
F.
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5) A malnourished middle-aged homeless man is brought to the emergency department. He is disoriented to person, place, and time and unable to walk without assistance. His temperature is 37.0 C (98.4 F), blood pressure is 134/80 mm Hg, pulse is 86/min, and respiratory rate is 18/min. Neurologic examination reveals lateral nystagmus. Evaluation of strength and sensation can not be performed. Which of the following is the most appropriate next step in management?
A. Administration of diazepam
B. Intravenous infusion of glucose
C. Intravenous infusion of thiamin
D. Toxicological screening
E. Neuroimaging studies
Explanation:
The correct answer is
C. The clinical picture is consistent with Wernicke-Korsakoff syndrome. Wernicke encephalopathy is characterized by nystagmus progressing to ophthalmoplegia, truncal ataxia and confusion. Korsakoff syndrome refers to alcohol-related amnesia and confabulation. Wernicke-Korsakoff syndrome is due to vitamin B1 deficiency, which is often seen in chronic alcoholics. This deficiency results in degeneration of periaqueductal gray matter. An alcoholic patient presenting with these symptoms should be treated with parenteral thiamin, 50-100 mg/day for the first few days followed by oral thiamin. Therapeutic doses of other water-soluble vitamins should also be administered because of the frequent concomitance of multiple vitamin deficiencies.
Administration of diazepam (choice A) is useful for treatment of alcohol withdrawal, which manifests with agitation and seizures.
Intravenous glucose infusion (choice B) should be avoided. This may in fact precipitate or aggravate a clinical picture of Wernicke encephalopathy in patients with thiamin deficiency.
Toxicological screening (choice D) and neuroimaging studies (choice E) would be of no use in this clinical situation.
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6) A 29-year-old professional tennis player presents with severe diarrhea and abdominal cramps over the past week. She has been in excellent health, and her only medical history is a urinary tract infection, treated 2 weeks ago with amoxicillin. Three days ago, she began having left lower quadrant abdominal cramps, followed by diarrhea that has become increasingly profuse. Over the past 24 hours, her temperature has increased to 38.4 C (101.1 F). Her physical examination is remarkable for moderate periumbilical and left lower quadrant tenderness. Her stool is guaiac negative. Which of the following would most likely be seen on sigmoidoscopy?
A. Deep rectal ulcers with normal sigmoid mucosa
B. Multiple sigmoid diverticula
C. Rectosigmoid edema and patchy exudates
D. Rectosigmoid stricture
E. Sessile sigmoid mass
Explanation:
The correct answer is
C. This patient has an acute colitis after the use of antibiotics. This is due to overgrowth of Clostridium difficile and can cause a colitis with the characteristic pseudomembranes, which are seen with sigmoidoscopy as patchy exudates. Microscopically, the exudates are composed of necrotic mucosal cells, inflammatory cells, bacteria, and fibrin. Although almost any antibiotic can lead to
C. difficile infection, commonly implicated culprits include clindamycin, broad spectrum penicillins such as ampicillin and amoxicillin (as in this patient), and cephalosporins. Initial treatment is with cessation of the original antibiotic, if it is still being used. Antiperistaltic drugs are contraindicated as they tend to prolong the illness. Most cases subside spontaneously within 10-12 days without other specific therapy.
The colitis usually seen in a patient with pseudomembranous colitis is a diffuse mucosal process and does not typically reveal localized deep ulcers (choice A).
Although left lower quadrant cramps may be seen with diverticula, they are generally seen in the older population and do not present with diarrhea (choice B).
There are no obstructive symptoms in this patient's history to suggest that she would have any strictures (choice D).
Similarly, this acute onset of diarrhea would not be expected to be the result of a sessile sigmoid mass (choice E).
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7) A 50-year-old man presents to the clinic with a year long history of having difficulty holding and using a writing instrument. He reports that he develops right hand and forearm spasms when writing, so that he cannot "bend his wrist the right way". He has been healthy all his life and is on no medications. He denies any dizziness or loss of consciousness or any history suggestive of a seizure. Which of the following is the most likely diagnosis?
A. Benign essential tremor
B. Carpal tunnel syndrome
C. Cervical radiculopathy
D. Focal dystonia
E. Parkinson Disease
Explanation:
The correct answer is
D. Such a writing cramp would be an example of focal dystonia of unknown cause. In this condition, the patient develops cramps with altered hand and arm posture when attempting a specific task such as writing. The other conditions may cause problems with writing as well but are usually not seen in isolation.
Benign essential tremor (choice A) features a distal upper extremity tremor during a task.
Carpal tunnel syndrome (choice B) is caused by median nerve compression and leads to hand weakness, which may affect writing.
Cervical radiculopathy (choice C) can lead to hand numbness and hyporeflexia.
Parkinson disease (choice E) presents with micrographia, bradykinesia, and often, a slow, "pill-rolling" tremor.
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8) A 45-year-old male suddenly loses consciousness and falls to the ground. He has been previously healthy and has been on no medications. There is no obvious evidence of trauma. An electrocardiogram reveals wide complex tachycardia at a rate of 300 beats per minute. Which of the following is the most appropriate intervention?
A. Obtain vital signs
B. Administer a bolus of intravenous lidocaine
C. Administer a thrombolytic agent
D. Perform asynchronous cardioversion
E. Perform synchronous cardioversion
Explanation:
The correct answer is
D. The patient is in ventricular tachycardia and is hemodynamically unstable as apparent from the loss of consciousness. He should be emergently cardioverted asynchronously with 200 joules of energy initially.
He is hemodynamically unstable, as apparent from his loss of consciousness. Precious time will be lost by obtaining vital signs (choice A) if cardioversion can be done now.
A lidocaine bolus should be given once a pulse and sinus rhythm is obtained to keep him out of ventricular tachycardia. This is especially beneficial if the event is ischemic in origin (choice B).
He may be having an infarct, and this may be the cause of his ventricular tachycardia. Emergently, the physician needs to restore sinus rhythm and then the man will be treated for myocardial infarction, if indicated (choice C).
If the patient were stable, synchronous cardioversion could be attempted (choice E).
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9) A 65-year-old man comes to medical attention because of multiple neurologic deficits, including loss of sensation in his right hand, weakness of the left lower leg, and a visual field deficit. He has smoked two packs of cigarettes daily for 40 years. His medical history is remarkable for asthma and emphysema. Examination of the fundus is unremarkable. His temperature is 37 C (98.6 F), blood pressure is 137/86 mm Hg, pulse is 86/min, and respirations are 24/min. MRI of the head reveals five different intracerebral lesions, ranging from 1 to 3 cm in main diameter and located at the gray-white matter junction in both cerebral hemispheres. The lesions are sharply demarcated, and contrast enhancement after gadolinium administration is present in all of them. Which of the following is the most likely diagnosis?
A. Abscesses
B. Arteriovenous malformations
C. Embolic infarcts
D. Metastases
E. Multifocal glioblastoma multiforme
Explanation:
The correct answer is
D. Awareness of the typical MRI/CT appearance of brain metastases is important because often patients present with cerebral metastases without prior history of cancer disease. Thus, a radiologic diagnosis of brain metastatic disease may prompt a search for the underlying primary tumor, which is often a lung carcinoma in men and lung or breast carcinoma in woman. Melanomas also have a peculiar propensity to metastasize to the brain. The typical radiologic features of brain metastases are summarized in this case: multiplicity of lesions, well-circumscribed borders, and location at the gray-white matter junction.
Multiple abscesses (choice A) may develop in patients with sepsis and, particularly, in association with conditions leading to septic emboli (e.g., infective endocarditis).
Arteriovenous malformations (AVMs) (choice B) are abnormal conglomerates of disorganized blood vessels composed of arteries, veins, and intermediate vessels with discontinuous elastic lamina. Intracerebral hemorrhage is their most frequent mode of clinical presentation.
Embolic infarcts (choice C) would be associated with wedge-shaped cortical lesions. Frequently, embolic infarcts are hemorrhagic.
Multifocal glioblastoma multiforme (GBM) (choice E), the most frequent malignant primary brain neoplasm, manifests as an ill-defined mass in the white matter. Contrast enhancement is usually present. Multifocal GBM is a rare event. Even so, the lesions are poorly circumscribed and centered in the white matter.
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10) A 22-year-old man is diagnosed with Crohn disease limited to the terminal ileum. His symptoms of mild right lower quadrant pain and postprandial diarrhea resolve after the initiation of treatment with mesalamine. Two years later, he develops recurrent episodes of abdominal distention, nausea, and vomiting after large meals. On two occasions, these symptoms are accompanied by inability to pass flatus or bowel movements. Which of the following has this patient most likely developed?
A. Fibrosis and a stricture in the terminal ileum
B. A fistula from the ileum to the sigmoid
C. Gastric outlet obstruction
D. An obstructing cecal carcinoma
E. An obstructing ileal carcinoid
Explanation:
The correct answer is
A. This patient with Crohn disease has developed symptoms of a small bowel obstruction, which is a common and important complication of this condition. This occurs in Crohn disease as a result of chronic transmural inflammation, which both partially destroys the normal bowel wall and constricts it with thick bands of fibrosis. Other important intestinal complications can include fistula formation and chronic abscesses. In addition, a wide variety of extraintestinal complications can include autoimmune diseases (arthritis, aphthous ulcers, erythema nodosum, pyoderma gangrenosum, eye involvement, ankylosing spondylitis primary sclerosing cholangitis) and complications related to disrupted bowel physiology (renal complications, including kidney stones and urinary tract obstruction, malabsorption, and amyloidosis secondary to longstanding inflammation).
A fistula from the ileum to the sigmoid (choice B) can develop in patients with Crohn disease but will present with symptoms of diarrhea (because of the bypass of a large portion of the colon) and not obstruction. Gastric outlet obstruction (choice C) may produce vomiting, usually of only partially digested foods, and does not usually result in significant abdominal distension. Furthermore, there is no impairment of passage of flatus or bowel movements.
Cecal carcinoma (choice D) can cause obstruction, but it would be extraordinarily rare in a 22-year-old man. Carcinoma is more likely to complicate ulcerative colitis than Crohn disease.
There is nothing in his history to suggest the development of carcinoid syndrome (choice E) in this young patient. These tumors, when they do occur, rarely present with a bowel obstruction, but may present with the carcinoid syndrome, i.e., facial flushing, diarrhea, wheezing, and tricuspid regurgitation.
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11) Ocular examination is performed on a patient during a routine medical check up. Retinal examination demonstrates a generalized retinal arteriolar constriction. The light reflex on the arterioles is broad and dull. Two areas of flame-shaped hemorrhages and multiple cotton wool spots are also seen. These findings are most suggestive of which of the following?
A. Central retinal artery occlusion
B. Central retinal vein occlusion
C. Hypertensive retinopathy
D. Non-proliferative diabetic retinopathy
E. Proliferative diabetic retinopathy
Explanation:
The correct answer is
C. The changes illustrated are those of hypertensive retinopathy, and may additionally include yellow hard exudates (due to lipid deposition in the retina) and a congested and edematous optic disk. Basically, what happens is that the eye tries to protect itself from the hypertension first with arteriolar constriction, and then with time, thickening of the arteriolar walls (producing the broad light reflex). The cotton wool spots are actually small, superficial foci of retinal ischemia, which occur when the arterioles squeeze down too hard. The hemorrhage and deposits occur because of vessel damage with leakage of contents. Hypertensive retinopathy can be seen in chronic essential hypertension, malignant hypertension, and toxemia of pregnancy. Treatment of the retinopathy is with control of the hypertension. (Practically, progression can be stopped and the hemorrhages will resolve, but the vessel changes remain.)
Central retinal artery occlusion (choice A) usually presents with sudden, unilateral blindness and produces a pale opaque fundus with a red fovea.
Central retinal vein occlusion (choice B) can cause painless visual loss and produces a congested and edematous fundus with numerous hemorrhages. The arteriolar changes of hypertensive retinopathy are not present.
Nonproliferative diabetic retinopathy (choice D) also causes hemorrhage and exudates in the retina, but additionally has distinctive microaneurysms (visible as red dots).
Proliferative diabetic retinopathy (choice E) has the changes of nonproliferative diabetic retinopathy with the addition of neovascularization with vessel growth into the vitreous.
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12) A 34 year-old female with HIV and active Pneumocystis pneumonia is admitted to the hospital. Her last CD4 count was 44 cells/mm3. She has been doing reasonably well since admission with a stable course on appropriate antibiotics. Two days into the hospitalization, she is found to be hypotensive and tachycardic. Her blood pressure is 80/40 mm Hg and her pulse is 110/min. Her temperature is 38.3 C (101 F) orally. Her extremities are cool and damp. Her mental status examination is normal. The remainder of her physical examination is unchanged. Which of the following is the most appropriate therapy?
A. Intravenous fluids
B. Intravenous pressor support
C. Central venous pressor support
D. Add additional antibiotics to treat empiric sepsis
E. Blood transfusion
Explanation:
The correct choice is
A. This patient is hypotensive but has minimal effects from the hypotension such as altered mental status or signs of shock. This blood pressure, however, is still not acceptable and the cause for it must be determined. In the interim, the symptom (low BP) must be treated. The standard therapy in all such situations is volume. This is a concept that ALL physicians must understand. Many times, newly graduated physicians worry about "CHF" or "wet lungs" with aggressive IV fluid support. Although in a non-emergent situation when a patients' blood pressure is not dangerously low, these are appropriate concerns, they are irrelevant in this situation. The key principal to understand is volume above all else. Since she is mentating well, there is no urgent indication for pharmacological blood pressure support and IV fluids are the absolute essential initial management tools for this patient.
Intravenous pressor support (choice B) is never given, as high dose vasopressors such as phenylephrine and dobutamine are only given via central venous access. On occasion, as temporary therapy, some vasopressors may be given by peripheral IV.
Central venous pressor support (choice C) is not indicated before an attempt at volume resuscitation has been made. If this patient were hemodynamically unstable, it might be appropriate to initiate this therapy at the same time as massive volume resuscitation is begun.
Adding additional antibiotics to treat empiric sepsis (choice D) is not appropriate until hemodynamic stability has been achieved. Remember the A, B, C's of emergency care. Concern for circulation before concern for antibiotic therapy. In addition, there is no evidence that this patient is suffering from sepsis syndrome. It may be simply that she is hypovolemic, given her fever and her illness.
Blood transfusion (choice E) is inappropriate unless the cause for the hypotension is blood loss or the patient is severely anemic and would benefit from blood component therapy.
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13) A 20-year-old man has had a persistent headache and a fever for a week. He now presents with a seizure. He has no prior medical history and is on no medications. On physical examination, he has a high-grade fever. He has left-sided weakness. He has a rooting reflex and appears disinhibited in his behavior. A CT scan of the head shows a ring-enhancing lesion in the right frontal lobe and an air-fluid level in the right frontal sinus. Which of the following will likely be seen on aspiration of the lesion?
A. Alpha hemolytic Streptococcus and mixed anaerobes
B. Bacteroides fragilis
C. Budding yeast organisms with hyphae
D. Small mononuclear cells suggestive of Burkitt lymphoma
E. Toxoplasma gondii cysts
Explanation:
The correct answer is
A. Neurosurgical aspiration of the lesion would most likely show alpha hemolytic streptococcus and mixed anaerobes. Brain abscesses can occur in young people. Frontal lobe disease is associated with sinusitis and reflects oral flora.
Bacteroides fragilis(choice B) is more commonly found in brain abscesses of otic origin. It would be a pathogen to suspect in a child with an inner ear infection.
Patients who are immunocompetent are rarely afflicted by a fungal abscess (choice C). Patients with diabetes or on steroids may be infected by Mucor. In people with severe acidosis, Zygomycetes can cause brain abscess, but these fungi have no yeast phase.
Primary brain lymphoma is rarely seen in immunocompetent patients. The Epstein-Barr virus has been linked to Burkitt lymphoma (choice D), a disease usually found in Africa.
Toxoplasmosis(choice E) is an infection often seen in an immunocompromised patient. It should be high on the differential diagnosis of any patient with HIV presenting with neurologic symptoms.
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14) A 32-year-old former heroin addict has a history of being treated for Pneumocystis carinii pneumonia twice in the past year. Over the past 2 weeks, he has developed bloody diarrhea, which occurred up to 12 times daily and is associated with urgency and the sensation of incomplete evacuation. He also complains of left lower quadrant cramping. He denies any history of homosexual activity. Which of the following organisms would most likely be responsible for his symptoms?
A. Cryptosporidium
B. Cytomegalovirus
C. Entamoeba histolytica
D. Enterotoxigenic Escherichia coli
E. Escherichia coli 0157
Explanation:
The correct answer is
B. A heroin addict treated twice for Pneumocystis carinii pneumonia most probably has clinical AIDS. The patient's sensation of incomplete evacuation suggests that his distal colon is involved; the fact that the diarrhea is bloody suggests that the causative agent is very destructive. Of the choices listed, both cytomegalovirus and Entamoeba histolytica may produce this symptom pattern, but cytomegalovirus is much more common than
E. histolytica in AIDS patients.
Cryptosporidium(choice A) causes a small bowel diarrheal syndrome with wasting.
E. histolytica(choice C) may occur in patients with HIV but is less common than cytomegalovirus infection.
Enterotoxigenic Escherichia coli(choice D) would produce a watery diarrhea.
E. coli 01-157 (choice E) is usually acquired by eating contaminated ground beef products and results in a hemolytic-uremic syndrome.
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15) A 60-year-old man is brought to the emergency room one hour after developing the sudden onset of headache. He appears confused to time and space, and is only able to tell his name and date of birth. The right pupil is dilated and poorly reactive to light. His wife relates that he has suffered from hypertension since the age of 40, but has not taken his antihypertensive treatment regularly. His temperature is 37 C (98.4 F), blood pressure is 170/100 mm Hg, pulse is 80/min and regular, and respirations are 20/min. Which of the following is the most appropriate next step in diagnosis?
A. Electroencephalographic examination
B. CT scan of the head
C. MRI scan of the head
D. Toxicological analysis of blood and urine
E. Lumbar puncture for CSF examination
Explanation:
The correct answer is
B. The history of poorly treated hypertension helps in the diagnosis. A hypertensive intracerebral bleeding should be suspected. CT studies of the brain are the most sensitive for detection of acute bleeding. MRI scan of the head (choice C) is usually more sensitive than CT scan for studies of intracerebral lesions, but less accurate in the early diagnosis of intracranial bleeding.
Electroencephalographic examination (choice A) would show non-diagnostic changes.
Toxicological analysis of blood and urine (choice D) are most useful in investigating coma of unknown origin. In particular, toxicological screening of urine may provide useful information in cases of suspected poisoning or intoxication.
Lumbar puncture for CSF examination (choice E) would not be advisable since this patient has evidence of increased intracranial pressure with uncal herniation (i.e. oculomotor paresis).
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16) A 41-year-old man presents with a 2-week history of fever, anorexia, weight loss, and fatigue. He is otherwise healthy and has not seen a physician recently, but did recently have his teeth cleaned. He is on no medications and has no allergies. He drinks alcohol only occasionally and denies IV drug use. On physical examination, he appears ill, with a temperature of 38.9 C (102 F) and a few petechiae in both eyes. There is a III/VI systolic ejection murmur consistent with mitral regurgitation and a pericardial rub. Blood is drawn and sent to the laboratory for culture. Which of the following is most likely to confirm the diagnosis?
A. ECG
B. Transthoracic echocardiogram (TTE)
C. Stress test
D. Transesophageal echocardiogram (TEE)
E. Cardiac catheterization
Explanation:
The correct answer is
D. The patient's history and physical examination are consistent with subacute bacterial endocarditis. The most effective diagnostic modality would be a transesophageal echocardiogram (TEE) in order to determine whether this patient has a valvular vegetation.
An ECG (choice A) will be useful to follow this patient for any evolving cardiac conduction delay. In the initial evaluation, it will help assess extent of conduction damage from the infection but will be of little help in the original diagnosis.
A transthoracic echocardiogram (TTE) (choice B) would be appropriate if a TEE were not possible. However, a TTE is much less sensitive than a TE
E.
A stress test (choice C) would be useful for risk-stratifying a patient with chest pain and coronary artery disease. If this patient was not febrile and was complaining of stable chest pain, a stress test could be conducted to assess the risk of a cardiac event.
Cardiac catheterization (choice E) would show the vegetation but is too invasive. This option is usually reserved for patients with an acute coronary syndrome arising from occlusion of a coronary artery.
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17) A 44-year-old obese woman presents to the emergency department complaining of 3 hours of severe abdominal pain. She has also had multiple episodes of vomiting during this time. She describes the pain as "worse than labor," and it radiates to the interscapular region. Her temperature is 38.9 C (102 F), and she has severe tenderness in her right upper quadrant. She reports that she has had multiple similar episodes in the past that have lasted approximately 30 minutes and then resolved spontaneously. Which of the following is most likely being obstructed by a gallstone?
A. Common bile duct
B. Common hepatic duct
C. Cystic duct
D. Pancreatic duct
E. Right hepatic duct
Explanation:
The correct answer is
C. This patient with acute cholecystitis has multiple risk factors, including female gender, obesity, and a classic history of prolonged biliary colic in association with fevers. The presentation illustrated is typical and results from obstruction of the cystic duct, which drains the gallbladder.
Obstruction of the common bile duct (choice A) or the pancreatic duct (choice D) will produce acute bacterial cholangitis, which would be demonstrated by Charcot's triad, i.e., right upper quadrant pain, fever, and jaundice.
Obstruction of either the common hepatic duct (choice B) or the right hepatic duct (choice E) may give a limited episode of cholangitis but will not cause cholecystitis, since the obstruction occurs in the biliary tree above the level of the entry of the cystic duct.
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18) The wife of an elderly patient with chronic obstructive pulmonary disease (COPD) calls the physician because her husband is extremely short of breath and appears "blue." The patient has a long history of COPD and has been compliant with his medications of albuterol inhalers, rotating antibiotics, and theophylline. His wife reports that, over the past several days, he has developed an increasingly productive cough. The patient is brought to the hospital by ambulance. At the hospital, the patient is barely responsive. He is breathing 100% oxygen via a tight-fitting face mask and no longer appears cyanotic. Which of the following is the most likely explanation for his unresponsiveness?
A. Aspiration
B. Hyperventilation
C. Hypoventilation
D. Myocardial ischemia
E. Pulmonary embolus
Explanation:
The correct answer is
C. This patient has been inappropriately treated with a high concentration of oxygen. Because he has a history of chronic obstructive pulmonary disease (COPD), he is most likely a CO2 retainer and depends on mild hypoxia to stimulate his respiratory drive. His wife clearly described that he was hypoxic ("blue"), which is consistent with an exacerbation of his underlying COPD and hypoxia. These patients cannot be treated with high concentrations of oxygen without prior intubation to ensure ventilation.
Aspiration (choice A) may occur during any period of diminished mental status but would not be the precipitating cause of that change in mental status.
Hyperventilation (choice B) would not cause this change in mental status.
Myocardial ischemia (choice D) may have occurred during his period of hypoxia but would not explain his unresponsiveness.
There is nothing described in this vignette that would suggest the patient is at risk for pulmonary embolus (choice E).
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19) The longtime primary care physician of an 85 year-old woman is asked to help mediate care between the family and the hospital's medical service. The patient sustained an anoxic brain injury during an in-hospital cardiac arrest one week ago in which the patient had a pulseless period for at least 5 minutes. On physical examination, her vital signs are normal and stable with the assistance of continuous mechanical ventilation. Pupillary and corneal reflexes are present bilaterally. There is episodic decorticate rigidity, but no purposeful movement present. An electroencephalogram (EEG) suggests severe, diffuse cortical damage. The patient's husband asks the physician if she is brain dead. Which of the following is the most appropriate response?
A. It is too early to predict brain death by the legal definition
B. The diagnosis of brain death can only legally be made by a neurologist
C. The decision on brain death must await the completion of a magnetic resonance image (MRI)
D. The presence of brain stem function and posturing rules out brain death, but the examination findings and supportive data suggest extensive brain damage
E. The suggestion of severe cortical damage by the EEG implies brain death
Explanation:
The correct answer is
D. As part of the widely accepted University of Pittsburgh criteria for brain death, the presence of either posturing or brain stem function (e.g.,. pupillary reflexes or corneal reflexes), as are present in this case, violates the brain criteria for the formal definition of brain death. That said, the fact that the patient has no purposeful activity one week after an anoxic brain injury bodes poorly for a meaningful neurological recovery. There are published studies that stratify long-term prognosis of such patients based upon neurological examinations made in the first 48 hours after injury.
While the passing of time often aids in the prognosticating of likely neurological recovery, the diagnosis of brain death can be made at any time and is not time-dependent (choice A).
Neurologists are often asked to help predict neurologic recovery and diagnose brain death (choice B), but any physician (generally two are required) may do so within current accepted diagnostic guidelines.
MRI (choice C) may help assess the extent of brain injury but has no role in the formal diagnosis of brain death.
The EEG, even when suggestive of minimal or no cortical function (choice E), does not exclude brainstem activity and therefore can not be used in isolation to make the diagnosis of brain death.
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20) A 32-year-old man presents complaining of severe pruritus over the past 2 weeks. He has a history of ulcerative colitis for the past 7 years, which has remained well controlled on sulfasalazine and cortisone enemas. His physical examination is unremarkable except for evidence of diffuse excoriations on his extremities and trunk. Laboratory studies reveal a mild iron deficiency anemia and normal electrolytes. Liver function tests are normal, except for an alkaline phosphatase that is 322 U/L (normal, <110 U/L). Which of the following is the most likely explanation for his symptoms?
A. Erythema nodosum
B. Hepatitis C
C. Primary biliary cirrhosis
D. Primary sclerosing cholangitis
E. Pyoderma gangrenosum
Explanation:
The correct answer is
D. This patient has had longstanding ulcerative colitis and has now developed pruritus in the setting of an elevated alkaline phosphatase. This is consistent with a diagnosis of primary sclerosing cholangitis, whose activity is not related to the activity of the associated ulcerative colitis. This sclerosing process involves both the intra- and extrahepatic ducts and is diagnosed by endoscopic retrograde cholangiopancreatography (ERCP). Primary sclerosing cholangitis occurs most often in young men and is commonly associated with inflammatory bowel disease, particularly ulcerative colitis. Classically, primary sclerosing cholangitis produces a triad of progressive fatigue, pruritus, and jaundice, although some patients will present with upper quadrant pain, fever, hepatosplenomegaly, or cirrhosis. The condition is worrisome because it may eventually progress to decompensated cirrhosis, portal hypertension, ascites, and liver failure. Treatment is generally supportive, with more specific measures as needed including antibacterial treatment for superimposed bacterial cholangitis, dilation by endoscopy or a transhepatic route of significant strictures, and ursodeoxycholic acid to relieve the pruritus. A variety of anti-inflammatory therapies (e.g., corticosteroids, azathioprine, methotrexate) have been tried but appear to have more adverse than beneficial effects. Liver transplantation appears to be the only true cure.
Although erythema nodosum and pyoderma gangrenosum can be skin conditions seen in association with ulcerative colitis, they do not present with pruritus and, furthermore, have characteristic findings on physical examination. Erythema nodosum (choice A) presents as tender, red nodules, typically found on the lower extremities. Pyoderma gangrenosum (choice E) are pustular, ulcerating lesions, also generally found on the extremities, which can be very painful.
There is no evidence of hepatocellular dysfunction or transaminase elevation, nor any history of hepatitis risk factors, so hepatitis C is unlikely (choice B).
Primary biliary cirrhosis (choice C) does in fact present with pruritus and an elevated alkaline phosphatase; however, it is typically seen in middle-aged women and has no association with ulcerative colitis.
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21) A 69-year-old retired physician is brought to the emergency department by his wife because of the onset of severe midabdominal pain. He awoke at approximately 4:00 AM with severe pain, which has gradually become "unbearable." He has a history of rheumatic fever, acute cholecystitis resulting in cholecystectomy, and a gastric ulcer. On physical examination, he appears acutely uncomfortable and complains of increasing pain with any movements. His temperature is 38.7 C (101.6 F), blood pressure is 160/90 mm Hg, and pulse is 104/min. He is anicteric and has dry mucous membranes. On abdominal examination, there is reduction in bowel sounds and diffuse tenderness and involuntary guarding to mild palpation. A rectal examination reveals brown, guaiac-negative stool. Upright chest x-ray and plain abdominal films reveal free air underneath the left hemidiaphragm. Which of the following is the most appropriate next step in management?
A. Abdominal CT scan
B. High-dose oral omeprazole
C. Histamine-2 receptor antagonist
D. Observation after placement of a nasogastric tube
E. Emergent laparotomy
Explanation:
The correct answer is
E. This patient has evidence of a perforated viscus, as demonstrated by the free air under the left hemidiaphragm. With a history of gastric ulcer, it is possible that he has perforated a recurrent ulcer. Plans should be made immediately for emergent exploratory laparotomy to prevent progression of his peritonitis. Peptic ulcers that perforate, producing free air in the abdominal cavity, are usually located in either the anterior wall of the duodenum or in the stomach. The description of the pain illustrated in the question stem is typical. The abdominal findings following perforation may be misleading, as diffuse abdominal pain, sometimes with prominent right lower quadrant involvement or radiation to either or both shoulder, may dominate the clinical picture rather than pain localized to the epigastrium. Breathing may exacerbate the pain. Prompt diagnosis with emergent laparotomy will lessen the risks of shock and establishment of a disseminated chemical (or superinfected) peritonitis.
An abdominal CT scan (choice A) would merely delay the definitive laparotomy.
Oral omeprazole and histamine-2 receptor antagonists (choices B and C) are effective medical therapies for gastric ulcer; however, they are superfluous in the management of a perforated ulcer.
Observation after placement of a nasogastric tube (choice D) is inappropriate given the obvious findings of a perforated viscus. Although a nasogastric tube may be placed prior to surgery, there is no role for conservative management for this patient.
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22) A 72-year-old alcoholic man is brought to the emergency department by his children. They state that he has become increasingly confused over the past week and is unsteady on his feet. On physical examination, ataxic gait, bilateral paresis of the lateral gaze, and vertical and horizontal nystagmus are noted. Which of the following is the most appropriate next step in management?
A. Administration of IV dextrose
B. Administration of IV mannitol
C. Administration of IV thiamine
D. CT of the brain with contrast
E. Lumbar puncture and examination of the CSF
Explanation:
The correct answer is
C. This patient has Wernicke encephalopathy. This acute disorder occurs most commonly in chronic alcoholics and consists of a clinical triad of ophthalmoplegia, ataxia, and global confusion. Affected patients may complain of double vision or difficulty with balance. There is almost always horizontal nystagmus on lateral gaze. Vertical nystagmus may be present in 50% of cases. Bilateral, often asymmetric, lateral rectus palsies are characteristic and may develop rapidly. Bilateral ptosis or an apparent internuclear ophthalmoplegia occurs rarely. The treatment is immediate IV thiamine. If given quickly enough, recovery begins promptly. Nearly all patients with Wernicke encephalopathy recover from the global confusional state, but many are left with a residual disorder of memory (Korsakoff syndrome).
If IV dextrose (choice A) is given before thiamine, the encephalopathy may worsen. IV mannitol (choice B) is helpful in conditions associated with increased intracranial pressure. CT of the brain with contrast (choice D) is an appropriate step but not the next appropriate step in management. IV thiamine should be given first. CT scan of the head is helpful to evaluate for structural lesions, such as subdural hematoma. Lumbar puncture and examination of CSF (choice E) is not the most appropriate next step either. In the workup of this patient, a lumbar puncture may help evaluate for a chronic infection, such as syphilis or tuberculosis or other processes causing those symptoms.
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23) A 24-year-old medical student complains of midepigastric pain that she describes as a "dull ache" that is relieved by eating. She has awakened from sleep on several occasions at 2 AM because of severe exacerbation of these symptoms, which are relieved with magnesium hydroxide. She takes frequent acetaminophen for menstrual cramping. Which of the following is the most likely cause of her symptoms?
A. Autonomous gastrin secretion
B. Gram-negative organism
C. Gram-positive organism
D. Prostaglandin inhibition
E. Vagal inhibition
Explanation:
The correct answer is
B. Peptic ulcer disease is strongly suggested by chronic midepigastric pain that is severe enough to awaken a patient at night and is relieved by antacids such as magnesium hydroxide. Although the differential diagnosis listed in textbooks for peptic ulcer disease is long, most patients with ulcer symptoms are either taking nonsteroidal anti-inflammatory agents (NSAIDs) or are colonized by the gram-negative organism Helicobacter pylori. This patient is not taking NSAIDs, so H. pylori colonization is the most likely answer. This organism colonizes the mucous layer that lines the stomach and disrupts the integrity of the mucus, predisposing for both chronic gastritis and peptic ulcer disease. Autonomous gastrin secretion (choice A) by a gastrinoma, as occurs in Zollinger-Ellison syndrome, would cause multiple large complicated ulcers, often in association with a secretory diarrhea. Choice C is wrong because H. pylori is gram negative, rather than gram positive. Prostaglandin inhibition (choice D) is the mechanism whereby NSAIDs cause ulcers, but this patient is not taking these drugs. Vagal inhibition (choice E) is actually a treatment for ulcer disease when performed as a vagotomy.
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24) A 70-year-old man presents to the emergency department complaining of abdominal pain. He describes the pain as crampy and primarily in his left lower quadrant. He has had minimal nausea, but complains of constipation. His past medical history is significant for hypertension, hyperlipidemia, gout, and diverticulosis. His medications include atenolol and simvastatin. He is allergic to penicillin. His temperature is 38.0 C (100.4 F), blood pressure is 140/60 mm Hg, pulse is 100/min, and respirations are 20/min. His physical examination is significant for tenderness to palpation at the left lower quadrant without rebound or guarding. His rectal examination is guaiac negative. His heart and lung examinations are unremarkable. Which of the following is the most likely diagnosis?
A. Appendicitis
B. Diverticulitis
C. Diverticulosis
D. Ischemic colitis
E. Sigmoid volvulus
Explanation:
The correct answer is
B. The presence of cramping, left lower quadrant pain with a localizing examination in a patient with known diverticulosis associated with fever and constipation is a classic presentation of diverticulitis. Appendicitis (choice A) becomes less likely given that the patient's pain is localized in the left lower quadrant. The classic pain of appendicitis is localized to the right lower quadrant. Diverticulosis (choice C) is incorrect since this term refers only to the presence of diverticula. The inflammation of a diverticulum(a), as suggested by this patient's history and examination, is termed diverticulitis. Ischemic colitis (choice D) is unlikely given that this condition is typically associated with abdominal pain on examination that is out of proportion to the presenting complaint, post-prandial abdominal discomfort, and rectal bleeding. Sigmoid volvulus (choice E) is unlikely since we have not been informed that the patient has a large region of hyperresonance over his abdomen, as would be expected with the bowel distension seen with volvulus.
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25) A 55-year-old man comes to the physician because of daily headaches awakening him in the early morning. Often, the pain is exacerbated by Valsalva maneuvers, such as coughing. He has rarely had headaches before. Common analgesics, such as aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs), have provided no benefits. The patient denies weight loss. He takes enalapril for moderately severe hypertension. Blood pressure is within normal limits at this time. Neurologic examination reveals mild hypoesthesia in the right hand and diminished strength in the right arm. Which of the following is the most appropriate next step in management?
A. Trial with different NSAIDs
B. Change in antihypertensive medication
C. Sumatriptan treatment
D. Neuroimaging studies
E. Lumbar puncture
Explanation:
The correct answer is
D. It is still controversial when to use neuroimaging studies (CT and/or MRI) in the diagnostic assessment of headache. Since the overwhelming majority of cases are due to migraine and tension headaches, neuroimaging is usually unnecessary. However, in the presence of new-onset headache, headache with atypical features, and especially in the presence of focal neurologic deficits (such as this case), neuroimaging studies should be performed to evaluate for intracranial mass-occupying lesions (e.g., tumors, bleeding). Trial with different NSAIDs (choice A) and a change in antihypertensive medication (choice B) would likely yield no benefit in this case and may delay the discovery of a serious underlying CNS lesion. Lumbar puncture (choice E) is not indicated in this case, since there is no clinical evidence of a neurologic process that may lead to diagnostic changes in the cerebrospinal fluid (CSF). Caution is strongly advised when there are signs of increased intracranial pressure, since lumbar puncture may precipitate cerebellar tonsillar herniation.
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26) A 10-year-old boy presents to the emergency department with headache, nausea, and vomiting for the past 3 days. Neurologic examination reveals nuchal rigidity and papilledema. A CT scan reveals an infiltrating cerebellar tumor, which is located in the midline (vermis), with plaque-like extensions onto the cerebellar surface. There is no cystic component. The fourth ventricle is compressed, and the third and lateral ventricles are dilated. Which of the following is the most likely diagnosis?
A. Ependymoma
B. Hemangioblastoma
C. Medulloblastoma
D. Meningioma
E. Oligodendroglioma
F. Pilocytic astrocytoma
Explanation:
The correct answer is
C. Primary brain tumors represent the second most common malignancy of childhood. Medulloblastoma is one of the most frequent. It grows from the cerebellar vermis and presents with signs and symptoms of hydrocephalus owing to obliteration of the fourth ventricle. Primitive neuroectodermal elements are thought to represent the cellular precursors of this anaplastic tumor. Medulloblastomas consist of sheets of undifferentiated cells with scanty cytoplasm and immunohistochemical features of neuronal or astrocytic differentiation. Extension to the cerebellar surface, producing so-called sugar coating or drop metastasis to the spinal cord through the CSF, represents a characteristic mode of spread of this tumor. Medulloblastomas are rapidly growing tumors. Probably because of this feature, they are also highly responsive to radiation and chemotherapy. Ependymoma (choice A) is another characteristic tumor of children and young adults. Its ependymal origin explains its usual proximity to the ventricles (either lateral or, more often in childhood, the fourth ventricle). In contrast to medulloblastoma, ependymoma grows as a mass filling the fourth ventricle. The prognosis depends on the possibility of complete excision and the degree of differentiation of the tumor. Usually, ependymomas tend to recur after surgical resection. Hemangioblastoma (choice B) is a benign tumor with a prominent capillary network. Between the capillaries are the truly neoplastic cells, which are probably of mesenchymal origin. The cerebellar hemispheres are the most common locations, where the tumor develops as a cyst with a mural contrast-enhancing nodule. It is associated with von Hippel-Lindau syndrome. Meningioma (choice D) is the most common benign intracranial tumor. It derives from meningothelial cells and appears as a dural-attached mass (extraaxial). Oligodendroglioma (choice E) represents about 5% of all brain tumors. It usually arises in the cerebral hemispheric white matter, and rarely occurs in children. As the name implies, the tumor is composed of neoplastic oligodendroglial cells, which closely resemble normal oligodendrocytes. Although it is a slowly growing tumor, its long-term prognosis is poor because of repeated recurrence after surgery and inevitable progression to high-grade tumor. Pilocytic astrocytoma (choice F) is a benign (WHO grade I), well-circumscribed astrocytoma of children and young adults. The two most common locations include the cerebellum (most commonly in the cerebellar hemisphere) and the diencephalic region. Complete surgical resection is feasible and usually curative in cerebellar tumors, but difficult in diencephalic tumors.
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27) A 24-year-old man with a known history of asthma presents to the emergency department complaining of 5 hours of severe wheezing and shortness of breath. He has used his bronchodilator inhaler six times during the past 5 hours but with only minimal relief. On physical examination, he appears dyspneic; his temperature is 37.4 C (99.3 F), blood pressure is 118/64 mm Hg, pulse is 106/min, and respirations are 32/min. There is visible use of the sternocleidomastoid muscles with each inspiration. A lung examination reveals bilateral diffuse inspiratory and expiratory wheezing with poor air movement and a prolonged expiratory phase. Which of the following will most likely be found on a chest x-ray film?
A. Bilateral interstitial infiltrate
B. Lobar consolidation
C. Pleural effusion
D. Pneumothorax
E. Normal findings
Explanation:
The correct answer is
E. This patient is presenting with an asthmatic attack and is not responding to his usual bronchodilator therapy. Although the findings are consistent with a severe asthmatic attack, i.e., the use of the sternocleidomastoid muscles for inspiration, these patients will generally have a normal chest x-ray film. The patient may have developed a low-grade (probably viral) infection, as suggested by his low-grade fever. However, the infections that are most likely to cause an exacerbation of asthma are usually of the upper respiratory tract; they would consequently be unlikely to produce any findings consistent with pneumonia. A bilateral interstitial infiltrate (choice A) would suggest pneumonia. Similarly, there are no signs or symptoms to suggest a lobar consolidation (choice B), consistent with a bacterial pneumonia, in that there is no mention of productive cough, fever, or rigors. There are no physical findings (dullness to percussion, decreased movement of diaphragm, decreased or absent breath sounds) or symptoms (pleuritic pain with breathing) to suggest a pleural effusion (choice C). Patients with asthma may develop a pneumothorax (choice D) because of the high intrathoracic pressures that occur during a severe attack. However, the physical findings would include absent breath sounds on examination, and this patient has symmetric bilateral breath sounds.
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28) A 44-year-old school bus driver presents to the emergency department complaining of severe abdominal pain. She reports that the pain began approximately 8 hours ago, after eating lunch at a fast-food restaurant. The pain has become increasingly severe and radiates to her back. She recalls a similar episode, lasting 3 hours, 2 months earlier and another episode, lasting 12 hours, during her last pregnancy. She is febrile, with a temperature of 38.1 C (100.5 F), and has right upper quadrant tenderness with deep palpation of this area. A rectal examination reveals brown, guaiac-negative stool. Her WBC is 12,900/mm3, and her hematocrit is 39%. Her total bilirubin is 2.1 mg/dL. Which of the following is the most appropriate diagnostic test?
A. CT scan of the abdomen and pelvis
B. Endoscopic retrograde cholangiopancreatography (ERCP)
C. HIDA scan
D. Percutaneous transhepatic cholangiogram (PTC)
E. Upper gastrointestinal barium study
Explanation:
The correct answer is
C. This patient has the classic presentation of acute cholecystitis. The episodes she had several months ago and during pregnancy suggest a prior history of biliary colic. A HIDA scan is a noninvasive nuclear medicine test that will reveal obstruction of the cystic duct, which is caused by an impacted gallstone and is the cause of acute cholecystitis. A CT scan (choice A) may show a distended gallbladder, but it is not as accurate as a HIDA scan for evaluating the cystic duct. Endoscopic retrograde cholangiopancreatography (ERCP) (choice B) is useful for evaluation of the common bile duct but is of a less value in evaluation of the cystic duct and, furthermore, is a far more invasive test than a HIDA scan. Percutaneous transhepatic cholangiography (PTC) (choice D) is an examination that is performed by the interventional radiologist by injecting the intrahepatic biliary tree percutaneously. This is rarely done since ERCP is a more accurate evaluation of the biliary of tree. PTC is of limited value in evaluating the cystic duct and it is an invasive procedure. An upper gastrointestinal barium study (choice E) may be useful for the evaluations of peptic ulcer disease but the symptoms here are far more suggestive of acute cholecystitis. Furthermore, if the patient has been vomiting she is unlikely to tolerate this examination.
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29) A 52-year-old man with a history of emphysema spends a 2-week vacation on a cruise ship. Shortly after returning home, he develops high fevers and becomes lethargic and disoriented. His wife describes that he has been coughing and short of breath since returning home. She also describes that he has vomited several times over the past 48 hours and has had diarrhea. On physical examination, he appears lethargic but arousable. He is disoriented to the current date. He has loud, coarse, rhonchi in both lung fields. His abdominal examination reveals mild tenderness over the liver edge. There is no splenomegaly or ascites present. His neurologic examination is nonfocal. Laboratory results are notable for an aspartate aminotransferase (AST) of 112 U/L and an alanine aminotransferase (ALT) of 157 U/L. Which of the following is the most appropriate treatment for this patient?
A. IV ceftazidime
B. IV erythromycin
C. IV gentamicin
D. IV nafcillin
E. IV vancomycin
Explanation:
The correct answer is
B. This patient, who has just returned from a cruise, has developed symptoms of toxicity in association with confusion, pulmonary findings, gastrointestinal complaints, and liver function test abnormalities. This should suggest the diagnosis of Legionnaires pneumonia, which he acquired through the ventilation system on the ship. These patients may appear quite toxic, and immediate initiation of therapy is essential since d
A. Crohn disease
B. Diverticulosis
C. Giardia infection
D. Irritable bowel syndrome
E. Ulcerative colitis
Explanation:
The correct answer is
D. This patient has typical crampy abdominal symptoms with alternating diarrhea and constipation. She is a young individual with chronic symptoms, which is very typical of irritable bowel syndrome. Patients with this diagnosis will generally have symptoms of pain related to meals or stress and an alteration in bowel habits. This change in bowel pattern may take the form of frequent loose stools versus constipation, or a combination of both. These patients have no physical findings or laboratory results to suggest an inflammatory process. Dietary changes and stress reduction are usually the goals of therapy, with antispasmodic drug therapy for symptomatic relief.
Crohn disease (choice A) is associated with a number of inflammatory findings, including tenderness on abdominal examination, mucopurulent or bloody stools, weight loss, and/or leukocytosis, and/or elevated erythrocyte sedimentation rate (ESR).
Diverticulosis (choice B) rarely happens in patients this young and will typically present with constipation without diarrheal symptoms.
Giardia infection (choice C) may cause chronic symptoms with abdominal cramping, but typically with symptoms of upper gastrointestinal involvement, such as nausea, vomiting, and eructations, since Giardia tends to live in the upper small bowel.
Ulcerative colitis (choice E) will present with bloody stools and evidence of an inflammatory condition, e.g., elevated ESR.
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2) A 34-year-old tax lawyer presents to his physician complaining of difficulty swallowing. On several occasions over the past few months, he was aware of meat becoming stuck in his mid-chest immediately after eating. After each episode, he had several hours of chest pain, which gradually resolved. On two occasions, he induced vomiting to obtain relief. Over the past 10 days, the swallowing difficulty has become worse, and he now has trouble with even soft foods and is limiting himself to pureed food. He has been taking ranitidine, magnesium hydroxide, and omeprazole for 4 years, but has remained symptomatic despite these measures. He has been smoking one pack of cigarettes daily for 15 years and denies any alcohol use. The physical examination is normal. Which of the following is the most likely explanation for these symptoms?
A. Diffuse esophageal spasm
B. Esophageal squamous carcinoma
C. Lower esophageal web
D. Peptic esophageal stricture
E. Scleroderma
Explanation:
The correct answer is
D. This patient presents with symptoms consistent with gradual luminal narrowing of the esophagus after many years of gastroesophageal reflux disease (GERD). These symptoms suggest the development of a benign peptic stricture. This may occur even if the patient is on medical therapy to reduce acid secretion, since many patients will continue to produce acid despite standard medical regimens and may require very high doses of proton pump inhibitors. Treatment consists of endoscopic dilation of this stricture and continued aggressive anti-reflux therapy.
Diffuse esophageal spasm (choice A) presents with "noncardiac chest pain," usually described as a mid-chest(squeezing chest pain. It typically presents with a motility-type dysphagia. Although GERD is a common underlying factor, the type of dysphagia in esophageal spasm would be consistent with a motility-type dysphagia, i.e., patient has difficulty with liquids as well as solids from the onset of his symptoms.
Squamous carcinoma (choice B) is not a sequelae of longstanding GER
D. Furthermore, his age makes it extremely unlikely that he would develop esophageal carcinoma (even with his history of smoking as a risk factor).
A lower esophageal web (choice C) or Schatzki ring produces dysphagia in an episodic pattern as foods that are greater in size than the diameter of the web, become lodged in the distal esophagus.
Scleroderma (choice E) could cause dysphagia, but this would be accompanied by Raynaud's phenomenon and characteristic changes in the skin. Additionally, scleroderma is about three times as common in women than in men.
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3) A 39-year-old man comes to medical attention because of a 1-year history of personality changes, abnormal involuntary movements, and memory dysfunction. His father and grandfather died in their 50s because of progressive mental deterioration accompanied by movement abnormalities. The patient is married but has no children. Neurologic examination and psychometric testing reveal difficulty in concentration, mild depression, and marked restlessness. During the examination, grimacing of the face and intermittent shrugging of the shoulders are noted. MRI examination of the brain reveals hyperintensity in the region of the caudate on T2-weighted images. Which of the following is the most likely diagnosis?
A. Creutzfeldt-Jakob disease
B. Gilles de la Tourette syndrome
C. Huntington disease
D. Sydenham chorea
E. Tardive dyskinesia
Explanation:
The correct answer is
C. The clinical manifestations and family history are consistent with Huntington disease. This autosomal dominant condition is caused by an unstable expansion of a CAG trinucleotide repeat in a gene encoding a novel protein named huntingtin. The age of clinical onset is commonly between 30 and 50 years, but may be as early as 5 years. Behavioral abnormalities and personality changes often precede the characteristic choreiform movements. Irritability, restlessness, and difficulty in concentration are among the most frequent early clinical manifestations. The pathologic substrate of this condition is degeneration of the striatal neurons, especially those in the caudate nucleus. Caudate nucleus changes may be appreciated on MRI examination or PET scans.
Creutzfeldt-Jacob disease (choice A) is characterized by rapidly progressive dementia associated with myoclonic movements. The disorder is familial in 10% to 15% of cases. It is probably caused by spontaneous mutations of the gene coding for prion protein.
The onset of Gilles de la Tourette syndrome (choice B) is usually between 2 and 15 years of age. Motor or phonic tics are the principal manifestations, including sniffing, blinking, spitting, grunts, coughs, and coprolalia.
Sydenham chorea (choice D) is one of the major Jones criteria for the diagnosis of rheumatic disease.
Tardive dyskinesia (choice E) is a late complication of antipsychotic drugs that block dopamine D2 receptors. It most commonly manifests with persistent chewing movements and intermittent protrusion of the tongue.
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4) A 64-year-old woman presents to her physician for management of her hypertension, which has been treated unsuccessfully for several years. She was recently hospitalized for pulmonary edema, and an echocardiogram at that time showed a moderately depressed ejection fraction. She was diagnosed with congestive heart failure. Her medications include a thiazide diuretic and a calcium channel blocker. She has an allergy to furosemide. Her review of systems is positive for two-pillow orthopnea and occasional paroxysmal nocturnal dyspnea. On physical examination, her blood pressure is 150/80 mm Hg, and her pulse is 80/min and regular. Her lungs are clear, and there are no extra heart sounds. Her extremities are without edema. Which of the following is the most appropriate management at this time?
A. Add an ACE inhibitor to her regimen
B. Add an angiotensin II receptor blocking agent to her regimen
C. Add hydralazine to her regimen
D. Increase the dose of her calcium channel blocker
E. Increase the dose of her thiazide diuretic
Explanation:
The correct answer is
A. This patient has both hypertension and congestive heart failure (CHF). An important concept to recognize in the treatment of medical conditions is that certain medications overlap syndromes and are efficacious in many areas. This "co-treatment" option maximizes each drug in a regimen and often addresses two or more issues simultaneously. In this case, ACE inhibitors have been shown to be very beneficial in prolonging the survival of CHF patients.
Adding an angiotensin II receptor blocking agent to a regimen (choice B) has become an alternative for ACE inhibitor therapy in patients who cannot tolerate these drugs for a variety of reasons. Although their efficacy in lowering blood pressure appears to be equivalent to that of ACE inhibitors, no data have shown their survival benefit to be similar to ACE inhibitors. Because such a clear mortality benefit has been demonstrated for ACE inhibitors, a compelling reason exists to use them preferentially in almost all patients with systolic dysfunction.
Adding hydralazine to her regimen (choice C) would certainly help to treat her blood pressure but will do nothing in terms of helping her CH
F.
Increasing the dose of her calcium channel blocker (choice D) or her thiazide diuretic (choice E) would most certainly aid in lowering her blood pressure, but neither of these medications has any significant utility for treating either systolic or diastolic CH
F.
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5) A malnourished middle-aged homeless man is brought to the emergency department. He is disoriented to person, place, and time and unable to walk without assistance. His temperature is 37.0 C (98.4 F), blood pressure is 134/80 mm Hg, pulse is 86/min, and respiratory rate is 18/min. Neurologic examination reveals lateral nystagmus. Evaluation of strength and sensation can not be performed. Which of the following is the most appropriate next step in management?
A. Administration of diazepam
B. Intravenous infusion of glucose
C. Intravenous infusion of thiamin
D. Toxicological screening
E. Neuroimaging studies
Explanation:
The correct answer is
C. The clinical picture is consistent with Wernicke-Korsakoff syndrome. Wernicke encephalopathy is characterized by nystagmus progressing to ophthalmoplegia, truncal ataxia and confusion. Korsakoff syndrome refers to alcohol-related amnesia and confabulation. Wernicke-Korsakoff syndrome is due to vitamin B1 deficiency, which is often seen in chronic alcoholics. This deficiency results in degeneration of periaqueductal gray matter. An alcoholic patient presenting with these symptoms should be treated with parenteral thiamin, 50-100 mg/day for the first few days followed by oral thiamin. Therapeutic doses of other water-soluble vitamins should also be administered because of the frequent concomitance of multiple vitamin deficiencies.
Administration of diazepam (choice A) is useful for treatment of alcohol withdrawal, which manifests with agitation and seizures.
Intravenous glucose infusion (choice B) should be avoided. This may in fact precipitate or aggravate a clinical picture of Wernicke encephalopathy in patients with thiamin deficiency.
Toxicological screening (choice D) and neuroimaging studies (choice E) would be of no use in this clinical situation.
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6) A 29-year-old professional tennis player presents with severe diarrhea and abdominal cramps over the past week. She has been in excellent health, and her only medical history is a urinary tract infection, treated 2 weeks ago with amoxicillin. Three days ago, she began having left lower quadrant abdominal cramps, followed by diarrhea that has become increasingly profuse. Over the past 24 hours, her temperature has increased to 38.4 C (101.1 F). Her physical examination is remarkable for moderate periumbilical and left lower quadrant tenderness. Her stool is guaiac negative. Which of the following would most likely be seen on sigmoidoscopy?
A. Deep rectal ulcers with normal sigmoid mucosa
B. Multiple sigmoid diverticula
C. Rectosigmoid edema and patchy exudates
D. Rectosigmoid stricture
E. Sessile sigmoid mass
Explanation:
The correct answer is
C. This patient has an acute colitis after the use of antibiotics. This is due to overgrowth of Clostridium difficile and can cause a colitis with the characteristic pseudomembranes, which are seen with sigmoidoscopy as patchy exudates. Microscopically, the exudates are composed of necrotic mucosal cells, inflammatory cells, bacteria, and fibrin. Although almost any antibiotic can lead to
C. difficile infection, commonly implicated culprits include clindamycin, broad spectrum penicillins such as ampicillin and amoxicillin (as in this patient), and cephalosporins. Initial treatment is with cessation of the original antibiotic, if it is still being used. Antiperistaltic drugs are contraindicated as they tend to prolong the illness. Most cases subside spontaneously within 10-12 days without other specific therapy.
The colitis usually seen in a patient with pseudomembranous colitis is a diffuse mucosal process and does not typically reveal localized deep ulcers (choice A).
Although left lower quadrant cramps may be seen with diverticula, they are generally seen in the older population and do not present with diarrhea (choice B).
There are no obstructive symptoms in this patient's history to suggest that she would have any strictures (choice D).
Similarly, this acute onset of diarrhea would not be expected to be the result of a sessile sigmoid mass (choice E).
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7) A 50-year-old man presents to the clinic with a year long history of having difficulty holding and using a writing instrument. He reports that he develops right hand and forearm spasms when writing, so that he cannot "bend his wrist the right way". He has been healthy all his life and is on no medications. He denies any dizziness or loss of consciousness or any history suggestive of a seizure. Which of the following is the most likely diagnosis?
A. Benign essential tremor
B. Carpal tunnel syndrome
C. Cervical radiculopathy
D. Focal dystonia
E. Parkinson Disease
Explanation:
The correct answer is
D. Such a writing cramp would be an example of focal dystonia of unknown cause. In this condition, the patient develops cramps with altered hand and arm posture when attempting a specific task such as writing. The other conditions may cause problems with writing as well but are usually not seen in isolation.
Benign essential tremor (choice A) features a distal upper extremity tremor during a task.
Carpal tunnel syndrome (choice B) is caused by median nerve compression and leads to hand weakness, which may affect writing.
Cervical radiculopathy (choice C) can lead to hand numbness and hyporeflexia.
Parkinson disease (choice E) presents with micrographia, bradykinesia, and often, a slow, "pill-rolling" tremor.
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8) A 45-year-old male suddenly loses consciousness and falls to the ground. He has been previously healthy and has been on no medications. There is no obvious evidence of trauma. An electrocardiogram reveals wide complex tachycardia at a rate of 300 beats per minute. Which of the following is the most appropriate intervention?
A. Obtain vital signs
B. Administer a bolus of intravenous lidocaine
C. Administer a thrombolytic agent
D. Perform asynchronous cardioversion
E. Perform synchronous cardioversion
Explanation:
The correct answer is
D. The patient is in ventricular tachycardia and is hemodynamically unstable as apparent from the loss of consciousness. He should be emergently cardioverted asynchronously with 200 joules of energy initially.
He is hemodynamically unstable, as apparent from his loss of consciousness. Precious time will be lost by obtaining vital signs (choice A) if cardioversion can be done now.
A lidocaine bolus should be given once a pulse and sinus rhythm is obtained to keep him out of ventricular tachycardia. This is especially beneficial if the event is ischemic in origin (choice B).
He may be having an infarct, and this may be the cause of his ventricular tachycardia. Emergently, the physician needs to restore sinus rhythm and then the man will be treated for myocardial infarction, if indicated (choice C).
If the patient were stable, synchronous cardioversion could be attempted (choice E).
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9) A 65-year-old man comes to medical attention because of multiple neurologic deficits, including loss of sensation in his right hand, weakness of the left lower leg, and a visual field deficit. He has smoked two packs of cigarettes daily for 40 years. His medical history is remarkable for asthma and emphysema. Examination of the fundus is unremarkable. His temperature is 37 C (98.6 F), blood pressure is 137/86 mm Hg, pulse is 86/min, and respirations are 24/min. MRI of the head reveals five different intracerebral lesions, ranging from 1 to 3 cm in main diameter and located at the gray-white matter junction in both cerebral hemispheres. The lesions are sharply demarcated, and contrast enhancement after gadolinium administration is present in all of them. Which of the following is the most likely diagnosis?
A. Abscesses
B. Arteriovenous malformations
C. Embolic infarcts
D. Metastases
E. Multifocal glioblastoma multiforme
Explanation:
The correct answer is
D. Awareness of the typical MRI/CT appearance of brain metastases is important because often patients present with cerebral metastases without prior history of cancer disease. Thus, a radiologic diagnosis of brain metastatic disease may prompt a search for the underlying primary tumor, which is often a lung carcinoma in men and lung or breast carcinoma in woman. Melanomas also have a peculiar propensity to metastasize to the brain. The typical radiologic features of brain metastases are summarized in this case: multiplicity of lesions, well-circumscribed borders, and location at the gray-white matter junction.
Multiple abscesses (choice A) may develop in patients with sepsis and, particularly, in association with conditions leading to septic emboli (e.g., infective endocarditis).
Arteriovenous malformations (AVMs) (choice B) are abnormal conglomerates of disorganized blood vessels composed of arteries, veins, and intermediate vessels with discontinuous elastic lamina. Intracerebral hemorrhage is their most frequent mode of clinical presentation.
Embolic infarcts (choice C) would be associated with wedge-shaped cortical lesions. Frequently, embolic infarcts are hemorrhagic.
Multifocal glioblastoma multiforme (GBM) (choice E), the most frequent malignant primary brain neoplasm, manifests as an ill-defined mass in the white matter. Contrast enhancement is usually present. Multifocal GBM is a rare event. Even so, the lesions are poorly circumscribed and centered in the white matter.
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10) A 22-year-old man is diagnosed with Crohn disease limited to the terminal ileum. His symptoms of mild right lower quadrant pain and postprandial diarrhea resolve after the initiation of treatment with mesalamine. Two years later, he develops recurrent episodes of abdominal distention, nausea, and vomiting after large meals. On two occasions, these symptoms are accompanied by inability to pass flatus or bowel movements. Which of the following has this patient most likely developed?
A. Fibrosis and a stricture in the terminal ileum
B. A fistula from the ileum to the sigmoid
C. Gastric outlet obstruction
D. An obstructing cecal carcinoma
E. An obstructing ileal carcinoid
Explanation:
The correct answer is
A. This patient with Crohn disease has developed symptoms of a small bowel obstruction, which is a common and important complication of this condition. This occurs in Crohn disease as a result of chronic transmural inflammation, which both partially destroys the normal bowel wall and constricts it with thick bands of fibrosis. Other important intestinal complications can include fistula formation and chronic abscesses. In addition, a wide variety of extraintestinal complications can include autoimmune diseases (arthritis, aphthous ulcers, erythema nodosum, pyoderma gangrenosum, eye involvement, ankylosing spondylitis primary sclerosing cholangitis) and complications related to disrupted bowel physiology (renal complications, including kidney stones and urinary tract obstruction, malabsorption, and amyloidosis secondary to longstanding inflammation).
A fistula from the ileum to the sigmoid (choice B) can develop in patients with Crohn disease but will present with symptoms of diarrhea (because of the bypass of a large portion of the colon) and not obstruction. Gastric outlet obstruction (choice C) may produce vomiting, usually of only partially digested foods, and does not usually result in significant abdominal distension. Furthermore, there is no impairment of passage of flatus or bowel movements.
Cecal carcinoma (choice D) can cause obstruction, but it would be extraordinarily rare in a 22-year-old man. Carcinoma is more likely to complicate ulcerative colitis than Crohn disease.
There is nothing in his history to suggest the development of carcinoid syndrome (choice E) in this young patient. These tumors, when they do occur, rarely present with a bowel obstruction, but may present with the carcinoid syndrome, i.e., facial flushing, diarrhea, wheezing, and tricuspid regurgitation.
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11) Ocular examination is performed on a patient during a routine medical check up. Retinal examination demonstrates a generalized retinal arteriolar constriction. The light reflex on the arterioles is broad and dull. Two areas of flame-shaped hemorrhages and multiple cotton wool spots are also seen. These findings are most suggestive of which of the following?
A. Central retinal artery occlusion
B. Central retinal vein occlusion
C. Hypertensive retinopathy
D. Non-proliferative diabetic retinopathy
E. Proliferative diabetic retinopathy
Explanation:
The correct answer is
C. The changes illustrated are those of hypertensive retinopathy, and may additionally include yellow hard exudates (due to lipid deposition in the retina) and a congested and edematous optic disk. Basically, what happens is that the eye tries to protect itself from the hypertension first with arteriolar constriction, and then with time, thickening of the arteriolar walls (producing the broad light reflex). The cotton wool spots are actually small, superficial foci of retinal ischemia, which occur when the arterioles squeeze down too hard. The hemorrhage and deposits occur because of vessel damage with leakage of contents. Hypertensive retinopathy can be seen in chronic essential hypertension, malignant hypertension, and toxemia of pregnancy. Treatment of the retinopathy is with control of the hypertension. (Practically, progression can be stopped and the hemorrhages will resolve, but the vessel changes remain.)
Central retinal artery occlusion (choice A) usually presents with sudden, unilateral blindness and produces a pale opaque fundus with a red fovea.
Central retinal vein occlusion (choice B) can cause painless visual loss and produces a congested and edematous fundus with numerous hemorrhages. The arteriolar changes of hypertensive retinopathy are not present.
Nonproliferative diabetic retinopathy (choice D) also causes hemorrhage and exudates in the retina, but additionally has distinctive microaneurysms (visible as red dots).
Proliferative diabetic retinopathy (choice E) has the changes of nonproliferative diabetic retinopathy with the addition of neovascularization with vessel growth into the vitreous.
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12) A 34 year-old female with HIV and active Pneumocystis pneumonia is admitted to the hospital. Her last CD4 count was 44 cells/mm3. She has been doing reasonably well since admission with a stable course on appropriate antibiotics. Two days into the hospitalization, she is found to be hypotensive and tachycardic. Her blood pressure is 80/40 mm Hg and her pulse is 110/min. Her temperature is 38.3 C (101 F) orally. Her extremities are cool and damp. Her mental status examination is normal. The remainder of her physical examination is unchanged. Which of the following is the most appropriate therapy?
A. Intravenous fluids
B. Intravenous pressor support
C. Central venous pressor support
D. Add additional antibiotics to treat empiric sepsis
E. Blood transfusion
Explanation:
The correct choice is
A. This patient is hypotensive but has minimal effects from the hypotension such as altered mental status or signs of shock. This blood pressure, however, is still not acceptable and the cause for it must be determined. In the interim, the symptom (low BP) must be treated. The standard therapy in all such situations is volume. This is a concept that ALL physicians must understand. Many times, newly graduated physicians worry about "CHF" or "wet lungs" with aggressive IV fluid support. Although in a non-emergent situation when a patients' blood pressure is not dangerously low, these are appropriate concerns, they are irrelevant in this situation. The key principal to understand is volume above all else. Since she is mentating well, there is no urgent indication for pharmacological blood pressure support and IV fluids are the absolute essential initial management tools for this patient.
Intravenous pressor support (choice B) is never given, as high dose vasopressors such as phenylephrine and dobutamine are only given via central venous access. On occasion, as temporary therapy, some vasopressors may be given by peripheral IV.
Central venous pressor support (choice C) is not indicated before an attempt at volume resuscitation has been made. If this patient were hemodynamically unstable, it might be appropriate to initiate this therapy at the same time as massive volume resuscitation is begun.
Adding additional antibiotics to treat empiric sepsis (choice D) is not appropriate until hemodynamic stability has been achieved. Remember the A, B, C's of emergency care. Concern for circulation before concern for antibiotic therapy. In addition, there is no evidence that this patient is suffering from sepsis syndrome. It may be simply that she is hypovolemic, given her fever and her illness.
Blood transfusion (choice E) is inappropriate unless the cause for the hypotension is blood loss or the patient is severely anemic and would benefit from blood component therapy.
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13) A 20-year-old man has had a persistent headache and a fever for a week. He now presents with a seizure. He has no prior medical history and is on no medications. On physical examination, he has a high-grade fever. He has left-sided weakness. He has a rooting reflex and appears disinhibited in his behavior. A CT scan of the head shows a ring-enhancing lesion in the right frontal lobe and an air-fluid level in the right frontal sinus. Which of the following will likely be seen on aspiration of the lesion?
A. Alpha hemolytic Streptococcus and mixed anaerobes
B. Bacteroides fragilis
C. Budding yeast organisms with hyphae
D. Small mononuclear cells suggestive of Burkitt lymphoma
E. Toxoplasma gondii cysts
Explanation:
The correct answer is
A. Neurosurgical aspiration of the lesion would most likely show alpha hemolytic streptococcus and mixed anaerobes. Brain abscesses can occur in young people. Frontal lobe disease is associated with sinusitis and reflects oral flora.
Bacteroides fragilis(choice B) is more commonly found in brain abscesses of otic origin. It would be a pathogen to suspect in a child with an inner ear infection.
Patients who are immunocompetent are rarely afflicted by a fungal abscess (choice C). Patients with diabetes or on steroids may be infected by Mucor. In people with severe acidosis, Zygomycetes can cause brain abscess, but these fungi have no yeast phase.
Primary brain lymphoma is rarely seen in immunocompetent patients. The Epstein-Barr virus has been linked to Burkitt lymphoma (choice D), a disease usually found in Africa.
Toxoplasmosis(choice E) is an infection often seen in an immunocompromised patient. It should be high on the differential diagnosis of any patient with HIV presenting with neurologic symptoms.
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14) A 32-year-old former heroin addict has a history of being treated for Pneumocystis carinii pneumonia twice in the past year. Over the past 2 weeks, he has developed bloody diarrhea, which occurred up to 12 times daily and is associated with urgency and the sensation of incomplete evacuation. He also complains of left lower quadrant cramping. He denies any history of homosexual activity. Which of the following organisms would most likely be responsible for his symptoms?
A. Cryptosporidium
B. Cytomegalovirus
C. Entamoeba histolytica
D. Enterotoxigenic Escherichia coli
E. Escherichia coli 0157
Explanation:
The correct answer is
B. A heroin addict treated twice for Pneumocystis carinii pneumonia most probably has clinical AIDS. The patient's sensation of incomplete evacuation suggests that his distal colon is involved; the fact that the diarrhea is bloody suggests that the causative agent is very destructive. Of the choices listed, both cytomegalovirus and Entamoeba histolytica may produce this symptom pattern, but cytomegalovirus is much more common than
E. histolytica in AIDS patients.
Cryptosporidium(choice A) causes a small bowel diarrheal syndrome with wasting.
E. histolytica(choice C) may occur in patients with HIV but is less common than cytomegalovirus infection.
Enterotoxigenic Escherichia coli(choice D) would produce a watery diarrhea.
E. coli 01-157 (choice E) is usually acquired by eating contaminated ground beef products and results in a hemolytic-uremic syndrome.
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15) A 60-year-old man is brought to the emergency room one hour after developing the sudden onset of headache. He appears confused to time and space, and is only able to tell his name and date of birth. The right pupil is dilated and poorly reactive to light. His wife relates that he has suffered from hypertension since the age of 40, but has not taken his antihypertensive treatment regularly. His temperature is 37 C (98.4 F), blood pressure is 170/100 mm Hg, pulse is 80/min and regular, and respirations are 20/min. Which of the following is the most appropriate next step in diagnosis?
A. Electroencephalographic examination
B. CT scan of the head
C. MRI scan of the head
D. Toxicological analysis of blood and urine
E. Lumbar puncture for CSF examination
Explanation:
The correct answer is
B. The history of poorly treated hypertension helps in the diagnosis. A hypertensive intracerebral bleeding should be suspected. CT studies of the brain are the most sensitive for detection of acute bleeding. MRI scan of the head (choice C) is usually more sensitive than CT scan for studies of intracerebral lesions, but less accurate in the early diagnosis of intracranial bleeding.
Electroencephalographic examination (choice A) would show non-diagnostic changes.
Toxicological analysis of blood and urine (choice D) are most useful in investigating coma of unknown origin. In particular, toxicological screening of urine may provide useful information in cases of suspected poisoning or intoxication.
Lumbar puncture for CSF examination (choice E) would not be advisable since this patient has evidence of increased intracranial pressure with uncal herniation (i.e. oculomotor paresis).
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16) A 41-year-old man presents with a 2-week history of fever, anorexia, weight loss, and fatigue. He is otherwise healthy and has not seen a physician recently, but did recently have his teeth cleaned. He is on no medications and has no allergies. He drinks alcohol only occasionally and denies IV drug use. On physical examination, he appears ill, with a temperature of 38.9 C (102 F) and a few petechiae in both eyes. There is a III/VI systolic ejection murmur consistent with mitral regurgitation and a pericardial rub. Blood is drawn and sent to the laboratory for culture. Which of the following is most likely to confirm the diagnosis?
A. ECG
B. Transthoracic echocardiogram (TTE)
C. Stress test
D. Transesophageal echocardiogram (TEE)
E. Cardiac catheterization
Explanation:
The correct answer is
D. The patient's history and physical examination are consistent with subacute bacterial endocarditis. The most effective diagnostic modality would be a transesophageal echocardiogram (TEE) in order to determine whether this patient has a valvular vegetation.
An ECG (choice A) will be useful to follow this patient for any evolving cardiac conduction delay. In the initial evaluation, it will help assess extent of conduction damage from the infection but will be of little help in the original diagnosis.
A transthoracic echocardiogram (TTE) (choice B) would be appropriate if a TEE were not possible. However, a TTE is much less sensitive than a TE
E.
A stress test (choice C) would be useful for risk-stratifying a patient with chest pain and coronary artery disease. If this patient was not febrile and was complaining of stable chest pain, a stress test could be conducted to assess the risk of a cardiac event.
Cardiac catheterization (choice E) would show the vegetation but is too invasive. This option is usually reserved for patients with an acute coronary syndrome arising from occlusion of a coronary artery.
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17) A 44-year-old obese woman presents to the emergency department complaining of 3 hours of severe abdominal pain. She has also had multiple episodes of vomiting during this time. She describes the pain as "worse than labor," and it radiates to the interscapular region. Her temperature is 38.9 C (102 F), and she has severe tenderness in her right upper quadrant. She reports that she has had multiple similar episodes in the past that have lasted approximately 30 minutes and then resolved spontaneously. Which of the following is most likely being obstructed by a gallstone?
A. Common bile duct
B. Common hepatic duct
C. Cystic duct
D. Pancreatic duct
E. Right hepatic duct
Explanation:
The correct answer is
C. This patient with acute cholecystitis has multiple risk factors, including female gender, obesity, and a classic history of prolonged biliary colic in association with fevers. The presentation illustrated is typical and results from obstruction of the cystic duct, which drains the gallbladder.
Obstruction of the common bile duct (choice A) or the pancreatic duct (choice D) will produce acute bacterial cholangitis, which would be demonstrated by Charcot's triad, i.e., right upper quadrant pain, fever, and jaundice.
Obstruction of either the common hepatic duct (choice B) or the right hepatic duct (choice E) may give a limited episode of cholangitis but will not cause cholecystitis, since the obstruction occurs in the biliary tree above the level of the entry of the cystic duct.
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18) The wife of an elderly patient with chronic obstructive pulmonary disease (COPD) calls the physician because her husband is extremely short of breath and appears "blue." The patient has a long history of COPD and has been compliant with his medications of albuterol inhalers, rotating antibiotics, and theophylline. His wife reports that, over the past several days, he has developed an increasingly productive cough. The patient is brought to the hospital by ambulance. At the hospital, the patient is barely responsive. He is breathing 100% oxygen via a tight-fitting face mask and no longer appears cyanotic. Which of the following is the most likely explanation for his unresponsiveness?
A. Aspiration
B. Hyperventilation
C. Hypoventilation
D. Myocardial ischemia
E. Pulmonary embolus
Explanation:
The correct answer is
C. This patient has been inappropriately treated with a high concentration of oxygen. Because he has a history of chronic obstructive pulmonary disease (COPD), he is most likely a CO2 retainer and depends on mild hypoxia to stimulate his respiratory drive. His wife clearly described that he was hypoxic ("blue"), which is consistent with an exacerbation of his underlying COPD and hypoxia. These patients cannot be treated with high concentrations of oxygen without prior intubation to ensure ventilation.
Aspiration (choice A) may occur during any period of diminished mental status but would not be the precipitating cause of that change in mental status.
Hyperventilation (choice B) would not cause this change in mental status.
Myocardial ischemia (choice D) may have occurred during his period of hypoxia but would not explain his unresponsiveness.
There is nothing described in this vignette that would suggest the patient is at risk for pulmonary embolus (choice E).
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19) The longtime primary care physician of an 85 year-old woman is asked to help mediate care between the family and the hospital's medical service. The patient sustained an anoxic brain injury during an in-hospital cardiac arrest one week ago in which the patient had a pulseless period for at least 5 minutes. On physical examination, her vital signs are normal and stable with the assistance of continuous mechanical ventilation. Pupillary and corneal reflexes are present bilaterally. There is episodic decorticate rigidity, but no purposeful movement present. An electroencephalogram (EEG) suggests severe, diffuse cortical damage. The patient's husband asks the physician if she is brain dead. Which of the following is the most appropriate response?
A. It is too early to predict brain death by the legal definition
B. The diagnosis of brain death can only legally be made by a neurologist
C. The decision on brain death must await the completion of a magnetic resonance image (MRI)
D. The presence of brain stem function and posturing rules out brain death, but the examination findings and supportive data suggest extensive brain damage
E. The suggestion of severe cortical damage by the EEG implies brain death
Explanation:
The correct answer is
D. As part of the widely accepted University of Pittsburgh criteria for brain death, the presence of either posturing or brain stem function (e.g.,. pupillary reflexes or corneal reflexes), as are present in this case, violates the brain criteria for the formal definition of brain death. That said, the fact that the patient has no purposeful activity one week after an anoxic brain injury bodes poorly for a meaningful neurological recovery. There are published studies that stratify long-term prognosis of such patients based upon neurological examinations made in the first 48 hours after injury.
While the passing of time often aids in the prognosticating of likely neurological recovery, the diagnosis of brain death can be made at any time and is not time-dependent (choice A).
Neurologists are often asked to help predict neurologic recovery and diagnose brain death (choice B), but any physician (generally two are required) may do so within current accepted diagnostic guidelines.
MRI (choice C) may help assess the extent of brain injury but has no role in the formal diagnosis of brain death.
The EEG, even when suggestive of minimal or no cortical function (choice E), does not exclude brainstem activity and therefore can not be used in isolation to make the diagnosis of brain death.
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20) A 32-year-old man presents complaining of severe pruritus over the past 2 weeks. He has a history of ulcerative colitis for the past 7 years, which has remained well controlled on sulfasalazine and cortisone enemas. His physical examination is unremarkable except for evidence of diffuse excoriations on his extremities and trunk. Laboratory studies reveal a mild iron deficiency anemia and normal electrolytes. Liver function tests are normal, except for an alkaline phosphatase that is 322 U/L (normal, <110 U/L). Which of the following is the most likely explanation for his symptoms?
A. Erythema nodosum
B. Hepatitis C
C. Primary biliary cirrhosis
D. Primary sclerosing cholangitis
E. Pyoderma gangrenosum
Explanation:
The correct answer is
D. This patient has had longstanding ulcerative colitis and has now developed pruritus in the setting of an elevated alkaline phosphatase. This is consistent with a diagnosis of primary sclerosing cholangitis, whose activity is not related to the activity of the associated ulcerative colitis. This sclerosing process involves both the intra- and extrahepatic ducts and is diagnosed by endoscopic retrograde cholangiopancreatography (ERCP). Primary sclerosing cholangitis occurs most often in young men and is commonly associated with inflammatory bowel disease, particularly ulcerative colitis. Classically, primary sclerosing cholangitis produces a triad of progressive fatigue, pruritus, and jaundice, although some patients will present with upper quadrant pain, fever, hepatosplenomegaly, or cirrhosis. The condition is worrisome because it may eventually progress to decompensated cirrhosis, portal hypertension, ascites, and liver failure. Treatment is generally supportive, with more specific measures as needed including antibacterial treatment for superimposed bacterial cholangitis, dilation by endoscopy or a transhepatic route of significant strictures, and ursodeoxycholic acid to relieve the pruritus. A variety of anti-inflammatory therapies (e.g., corticosteroids, azathioprine, methotrexate) have been tried but appear to have more adverse than beneficial effects. Liver transplantation appears to be the only true cure.
Although erythema nodosum and pyoderma gangrenosum can be skin conditions seen in association with ulcerative colitis, they do not present with pruritus and, furthermore, have characteristic findings on physical examination. Erythema nodosum (choice A) presents as tender, red nodules, typically found on the lower extremities. Pyoderma gangrenosum (choice E) are pustular, ulcerating lesions, also generally found on the extremities, which can be very painful.
There is no evidence of hepatocellular dysfunction or transaminase elevation, nor any history of hepatitis risk factors, so hepatitis C is unlikely (choice B).
Primary biliary cirrhosis (choice C) does in fact present with pruritus and an elevated alkaline phosphatase; however, it is typically seen in middle-aged women and has no association with ulcerative colitis.
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21) A 69-year-old retired physician is brought to the emergency department by his wife because of the onset of severe midabdominal pain. He awoke at approximately 4:00 AM with severe pain, which has gradually become "unbearable." He has a history of rheumatic fever, acute cholecystitis resulting in cholecystectomy, and a gastric ulcer. On physical examination, he appears acutely uncomfortable and complains of increasing pain with any movements. His temperature is 38.7 C (101.6 F), blood pressure is 160/90 mm Hg, and pulse is 104/min. He is anicteric and has dry mucous membranes. On abdominal examination, there is reduction in bowel sounds and diffuse tenderness and involuntary guarding to mild palpation. A rectal examination reveals brown, guaiac-negative stool. Upright chest x-ray and plain abdominal films reveal free air underneath the left hemidiaphragm. Which of the following is the most appropriate next step in management?
A. Abdominal CT scan
B. High-dose oral omeprazole
C. Histamine-2 receptor antagonist
D. Observation after placement of a nasogastric tube
E. Emergent laparotomy
Explanation:
The correct answer is
E. This patient has evidence of a perforated viscus, as demonstrated by the free air under the left hemidiaphragm. With a history of gastric ulcer, it is possible that he has perforated a recurrent ulcer. Plans should be made immediately for emergent exploratory laparotomy to prevent progression of his peritonitis. Peptic ulcers that perforate, producing free air in the abdominal cavity, are usually located in either the anterior wall of the duodenum or in the stomach. The description of the pain illustrated in the question stem is typical. The abdominal findings following perforation may be misleading, as diffuse abdominal pain, sometimes with prominent right lower quadrant involvement or radiation to either or both shoulder, may dominate the clinical picture rather than pain localized to the epigastrium. Breathing may exacerbate the pain. Prompt diagnosis with emergent laparotomy will lessen the risks of shock and establishment of a disseminated chemical (or superinfected) peritonitis.
An abdominal CT scan (choice A) would merely delay the definitive laparotomy.
Oral omeprazole and histamine-2 receptor antagonists (choices B and C) are effective medical therapies for gastric ulcer; however, they are superfluous in the management of a perforated ulcer.
Observation after placement of a nasogastric tube (choice D) is inappropriate given the obvious findings of a perforated viscus. Although a nasogastric tube may be placed prior to surgery, there is no role for conservative management for this patient.
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22) A 72-year-old alcoholic man is brought to the emergency department by his children. They state that he has become increasingly confused over the past week and is unsteady on his feet. On physical examination, ataxic gait, bilateral paresis of the lateral gaze, and vertical and horizontal nystagmus are noted. Which of the following is the most appropriate next step in management?
A. Administration of IV dextrose
B. Administration of IV mannitol
C. Administration of IV thiamine
D. CT of the brain with contrast
E. Lumbar puncture and examination of the CSF
Explanation:
The correct answer is
C. This patient has Wernicke encephalopathy. This acute disorder occurs most commonly in chronic alcoholics and consists of a clinical triad of ophthalmoplegia, ataxia, and global confusion. Affected patients may complain of double vision or difficulty with balance. There is almost always horizontal nystagmus on lateral gaze. Vertical nystagmus may be present in 50% of cases. Bilateral, often asymmetric, lateral rectus palsies are characteristic and may develop rapidly. Bilateral ptosis or an apparent internuclear ophthalmoplegia occurs rarely. The treatment is immediate IV thiamine. If given quickly enough, recovery begins promptly. Nearly all patients with Wernicke encephalopathy recover from the global confusional state, but many are left with a residual disorder of memory (Korsakoff syndrome).
If IV dextrose (choice A) is given before thiamine, the encephalopathy may worsen. IV mannitol (choice B) is helpful in conditions associated with increased intracranial pressure. CT of the brain with contrast (choice D) is an appropriate step but not the next appropriate step in management. IV thiamine should be given first. CT scan of the head is helpful to evaluate for structural lesions, such as subdural hematoma. Lumbar puncture and examination of CSF (choice E) is not the most appropriate next step either. In the workup of this patient, a lumbar puncture may help evaluate for a chronic infection, such as syphilis or tuberculosis or other processes causing those symptoms.
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23) A 24-year-old medical student complains of midepigastric pain that she describes as a "dull ache" that is relieved by eating. She has awakened from sleep on several occasions at 2 AM because of severe exacerbation of these symptoms, which are relieved with magnesium hydroxide. She takes frequent acetaminophen for menstrual cramping. Which of the following is the most likely cause of her symptoms?
A. Autonomous gastrin secretion
B. Gram-negative organism
C. Gram-positive organism
D. Prostaglandin inhibition
E. Vagal inhibition
Explanation:
The correct answer is
B. Peptic ulcer disease is strongly suggested by chronic midepigastric pain that is severe enough to awaken a patient at night and is relieved by antacids such as magnesium hydroxide. Although the differential diagnosis listed in textbooks for peptic ulcer disease is long, most patients with ulcer symptoms are either taking nonsteroidal anti-inflammatory agents (NSAIDs) or are colonized by the gram-negative organism Helicobacter pylori. This patient is not taking NSAIDs, so H. pylori colonization is the most likely answer. This organism colonizes the mucous layer that lines the stomach and disrupts the integrity of the mucus, predisposing for both chronic gastritis and peptic ulcer disease. Autonomous gastrin secretion (choice A) by a gastrinoma, as occurs in Zollinger-Ellison syndrome, would cause multiple large complicated ulcers, often in association with a secretory diarrhea. Choice C is wrong because H. pylori is gram negative, rather than gram positive. Prostaglandin inhibition (choice D) is the mechanism whereby NSAIDs cause ulcers, but this patient is not taking these drugs. Vagal inhibition (choice E) is actually a treatment for ulcer disease when performed as a vagotomy.
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24) A 70-year-old man presents to the emergency department complaining of abdominal pain. He describes the pain as crampy and primarily in his left lower quadrant. He has had minimal nausea, but complains of constipation. His past medical history is significant for hypertension, hyperlipidemia, gout, and diverticulosis. His medications include atenolol and simvastatin. He is allergic to penicillin. His temperature is 38.0 C (100.4 F), blood pressure is 140/60 mm Hg, pulse is 100/min, and respirations are 20/min. His physical examination is significant for tenderness to palpation at the left lower quadrant without rebound or guarding. His rectal examination is guaiac negative. His heart and lung examinations are unremarkable. Which of the following is the most likely diagnosis?
A. Appendicitis
B. Diverticulitis
C. Diverticulosis
D. Ischemic colitis
E. Sigmoid volvulus
Explanation:
The correct answer is
B. The presence of cramping, left lower quadrant pain with a localizing examination in a patient with known diverticulosis associated with fever and constipation is a classic presentation of diverticulitis. Appendicitis (choice A) becomes less likely given that the patient's pain is localized in the left lower quadrant. The classic pain of appendicitis is localized to the right lower quadrant. Diverticulosis (choice C) is incorrect since this term refers only to the presence of diverticula. The inflammation of a diverticulum(a), as suggested by this patient's history and examination, is termed diverticulitis. Ischemic colitis (choice D) is unlikely given that this condition is typically associated with abdominal pain on examination that is out of proportion to the presenting complaint, post-prandial abdominal discomfort, and rectal bleeding. Sigmoid volvulus (choice E) is unlikely since we have not been informed that the patient has a large region of hyperresonance over his abdomen, as would be expected with the bowel distension seen with volvulus.
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25) A 55-year-old man comes to the physician because of daily headaches awakening him in the early morning. Often, the pain is exacerbated by Valsalva maneuvers, such as coughing. He has rarely had headaches before. Common analgesics, such as aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs), have provided no benefits. The patient denies weight loss. He takes enalapril for moderately severe hypertension. Blood pressure is within normal limits at this time. Neurologic examination reveals mild hypoesthesia in the right hand and diminished strength in the right arm. Which of the following is the most appropriate next step in management?
A. Trial with different NSAIDs
B. Change in antihypertensive medication
C. Sumatriptan treatment
D. Neuroimaging studies
E. Lumbar puncture
Explanation:
The correct answer is
D. It is still controversial when to use neuroimaging studies (CT and/or MRI) in the diagnostic assessment of headache. Since the overwhelming majority of cases are due to migraine and tension headaches, neuroimaging is usually unnecessary. However, in the presence of new-onset headache, headache with atypical features, and especially in the presence of focal neurologic deficits (such as this case), neuroimaging studies should be performed to evaluate for intracranial mass-occupying lesions (e.g., tumors, bleeding). Trial with different NSAIDs (choice A) and a change in antihypertensive medication (choice B) would likely yield no benefit in this case and may delay the discovery of a serious underlying CNS lesion. Lumbar puncture (choice E) is not indicated in this case, since there is no clinical evidence of a neurologic process that may lead to diagnostic changes in the cerebrospinal fluid (CSF). Caution is strongly advised when there are signs of increased intracranial pressure, since lumbar puncture may precipitate cerebellar tonsillar herniation.
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26) A 10-year-old boy presents to the emergency department with headache, nausea, and vomiting for the past 3 days. Neurologic examination reveals nuchal rigidity and papilledema. A CT scan reveals an infiltrating cerebellar tumor, which is located in the midline (vermis), with plaque-like extensions onto the cerebellar surface. There is no cystic component. The fourth ventricle is compressed, and the third and lateral ventricles are dilated. Which of the following is the most likely diagnosis?
A. Ependymoma
B. Hemangioblastoma
C. Medulloblastoma
D. Meningioma
E. Oligodendroglioma
F. Pilocytic astrocytoma
Explanation:
The correct answer is
C. Primary brain tumors represent the second most common malignancy of childhood. Medulloblastoma is one of the most frequent. It grows from the cerebellar vermis and presents with signs and symptoms of hydrocephalus owing to obliteration of the fourth ventricle. Primitive neuroectodermal elements are thought to represent the cellular precursors of this anaplastic tumor. Medulloblastomas consist of sheets of undifferentiated cells with scanty cytoplasm and immunohistochemical features of neuronal or astrocytic differentiation. Extension to the cerebellar surface, producing so-called sugar coating or drop metastasis to the spinal cord through the CSF, represents a characteristic mode of spread of this tumor. Medulloblastomas are rapidly growing tumors. Probably because of this feature, they are also highly responsive to radiation and chemotherapy. Ependymoma (choice A) is another characteristic tumor of children and young adults. Its ependymal origin explains its usual proximity to the ventricles (either lateral or, more often in childhood, the fourth ventricle). In contrast to medulloblastoma, ependymoma grows as a mass filling the fourth ventricle. The prognosis depends on the possibility of complete excision and the degree of differentiation of the tumor. Usually, ependymomas tend to recur after surgical resection. Hemangioblastoma (choice B) is a benign tumor with a prominent capillary network. Between the capillaries are the truly neoplastic cells, which are probably of mesenchymal origin. The cerebellar hemispheres are the most common locations, where the tumor develops as a cyst with a mural contrast-enhancing nodule. It is associated with von Hippel-Lindau syndrome. Meningioma (choice D) is the most common benign intracranial tumor. It derives from meningothelial cells and appears as a dural-attached mass (extraaxial). Oligodendroglioma (choice E) represents about 5% of all brain tumors. It usually arises in the cerebral hemispheric white matter, and rarely occurs in children. As the name implies, the tumor is composed of neoplastic oligodendroglial cells, which closely resemble normal oligodendrocytes. Although it is a slowly growing tumor, its long-term prognosis is poor because of repeated recurrence after surgery and inevitable progression to high-grade tumor. Pilocytic astrocytoma (choice F) is a benign (WHO grade I), well-circumscribed astrocytoma of children and young adults. The two most common locations include the cerebellum (most commonly in the cerebellar hemisphere) and the diencephalic region. Complete surgical resection is feasible and usually curative in cerebellar tumors, but difficult in diencephalic tumors.
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27) A 24-year-old man with a known history of asthma presents to the emergency department complaining of 5 hours of severe wheezing and shortness of breath. He has used his bronchodilator inhaler six times during the past 5 hours but with only minimal relief. On physical examination, he appears dyspneic; his temperature is 37.4 C (99.3 F), blood pressure is 118/64 mm Hg, pulse is 106/min, and respirations are 32/min. There is visible use of the sternocleidomastoid muscles with each inspiration. A lung examination reveals bilateral diffuse inspiratory and expiratory wheezing with poor air movement and a prolonged expiratory phase. Which of the following will most likely be found on a chest x-ray film?
A. Bilateral interstitial infiltrate
B. Lobar consolidation
C. Pleural effusion
D. Pneumothorax
E. Normal findings
Explanation:
The correct answer is
E. This patient is presenting with an asthmatic attack and is not responding to his usual bronchodilator therapy. Although the findings are consistent with a severe asthmatic attack, i.e., the use of the sternocleidomastoid muscles for inspiration, these patients will generally have a normal chest x-ray film. The patient may have developed a low-grade (probably viral) infection, as suggested by his low-grade fever. However, the infections that are most likely to cause an exacerbation of asthma are usually of the upper respiratory tract; they would consequently be unlikely to produce any findings consistent with pneumonia. A bilateral interstitial infiltrate (choice A) would suggest pneumonia. Similarly, there are no signs or symptoms to suggest a lobar consolidation (choice B), consistent with a bacterial pneumonia, in that there is no mention of productive cough, fever, or rigors. There are no physical findings (dullness to percussion, decreased movement of diaphragm, decreased or absent breath sounds) or symptoms (pleuritic pain with breathing) to suggest a pleural effusion (choice C). Patients with asthma may develop a pneumothorax (choice D) because of the high intrathoracic pressures that occur during a severe attack. However, the physical findings would include absent breath sounds on examination, and this patient has symmetric bilateral breath sounds.
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28) A 44-year-old school bus driver presents to the emergency department complaining of severe abdominal pain. She reports that the pain began approximately 8 hours ago, after eating lunch at a fast-food restaurant. The pain has become increasingly severe and radiates to her back. She recalls a similar episode, lasting 3 hours, 2 months earlier and another episode, lasting 12 hours, during her last pregnancy. She is febrile, with a temperature of 38.1 C (100.5 F), and has right upper quadrant tenderness with deep palpation of this area. A rectal examination reveals brown, guaiac-negative stool. Her WBC is 12,900/mm3, and her hematocrit is 39%. Her total bilirubin is 2.1 mg/dL. Which of the following is the most appropriate diagnostic test?
A. CT scan of the abdomen and pelvis
B. Endoscopic retrograde cholangiopancreatography (ERCP)
C. HIDA scan
D. Percutaneous transhepatic cholangiogram (PTC)
E. Upper gastrointestinal barium study
Explanation:
The correct answer is
C. This patient has the classic presentation of acute cholecystitis. The episodes she had several months ago and during pregnancy suggest a prior history of biliary colic. A HIDA scan is a noninvasive nuclear medicine test that will reveal obstruction of the cystic duct, which is caused by an impacted gallstone and is the cause of acute cholecystitis. A CT scan (choice A) may show a distended gallbladder, but it is not as accurate as a HIDA scan for evaluating the cystic duct. Endoscopic retrograde cholangiopancreatography (ERCP) (choice B) is useful for evaluation of the common bile duct but is of a less value in evaluation of the cystic duct and, furthermore, is a far more invasive test than a HIDA scan. Percutaneous transhepatic cholangiography (PTC) (choice D) is an examination that is performed by the interventional radiologist by injecting the intrahepatic biliary tree percutaneously. This is rarely done since ERCP is a more accurate evaluation of the biliary of tree. PTC is of limited value in evaluating the cystic duct and it is an invasive procedure. An upper gastrointestinal barium study (choice E) may be useful for the evaluations of peptic ulcer disease but the symptoms here are far more suggestive of acute cholecystitis. Furthermore, if the patient has been vomiting she is unlikely to tolerate this examination.
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29) A 52-year-old man with a history of emphysema spends a 2-week vacation on a cruise ship. Shortly after returning home, he develops high fevers and becomes lethargic and disoriented. His wife describes that he has been coughing and short of breath since returning home. She also describes that he has vomited several times over the past 48 hours and has had diarrhea. On physical examination, he appears lethargic but arousable. He is disoriented to the current date. He has loud, coarse, rhonchi in both lung fields. His abdominal examination reveals mild tenderness over the liver edge. There is no splenomegaly or ascites present. His neurologic examination is nonfocal. Laboratory results are notable for an aspartate aminotransferase (AST) of 112 U/L and an alanine aminotransferase (ALT) of 157 U/L. Which of the following is the most appropriate treatment for this patient?
A. IV ceftazidime
B. IV erythromycin
C. IV gentamicin
D. IV nafcillin
E. IV vancomycin
Explanation:
The correct answer is
B. This patient, who has just returned from a cruise, has developed symptoms of toxicity in association with confusion, pulmonary findings, gastrointestinal complaints, and liver function test abnormalities. This should suggest the diagnosis of Legionnaires pneumonia, which he acquired through the ventilation system on the ship. These patients may appear quite toxic, and immediate initiation of therapy is essential since d