q-f17 - npng

[ArchivalUser]

An 88-year-old man is hospitalized for pneumonia and poor nutritional intake. On physical examination, he is coughing. The temperature is 37.8 °C (100 °F), pulse rate is 90/min, and respiration rate is 16/min. Chest examination reveals crackles in the left lower lobe, and the chest radiograph confirms the diagnosis of pneumonia. Antibiotic therapy is begun, and the patient's cough resolves within 3 days and the vital signs return to normal.

On hospital day 4, the patient becomes inattentive, confused, and drowsy, with apparent hallucinations and fluctuating mental status. His vital signs remain normal, and other than his mental status, his physical examination is normal

Which of the following is the most likely cause of this patient's change in mental status?

A. Alcohol abstinence syndrome
B. Drug reaction
C. Hyponatremia
D. Hypoxemia
E. Meningitis

[ArchivalUser]

AA

[ArchivalUser]

A..

[ArchivalUser]

AAAA

[ArchivalUser]

Ans is C.

Hyponatremia is a common and dangerous cause of delirium in hospitalized patients. Undernourished elderly patients are at particularly high risk for this condition and should always be checked when they may be susceptible to hyponatremia and exhibit changes in their mental status.

Meningitis may accompany pneumonia; however, because this patient has responded to treatment and has been afebrile for 2 days, he is unlikely to be experiencing meningitis at this late date. In addition, he has no physical examination findings indicative of meningitis. Alcohol abstinence syndrome is always a consideration when delirium develops without a clear explanation in a hospitalized patient. Minor withdrawal symptoms and seizures usually occur within 6 to 36 hours of abstinence, whereas delirium tremens is a late occurring event, occurring 48 to 96 hours after alcohol cessation. This patient's symptoms are occurring too late for alcohol withdrawal syndrome, but the timing is compatible with delirium tremens; however, delirium tremens is characteristically accompanied by tachycardia, agitation, tremulousness, and mild fever, which are notably absent in this patient. When hypoxemia leads to delirium, the patient is often agitated rather than drowsy. Furthermore, it would be unusual for a patient to have normal vital signs with newly worsening hypoxemia. Antibiotic therapy rarely causes drug-induced delirium.