nbme 3 vomiting and diarrhea - schenki

[ArchivalUser]

A previously healthy 6-month-old boy is brought to the physician because of a 12-hour history of vomiting and diarrhea. He vomits after all feedings, the vomitus does not contain blood or bile. His mother says that he has had fewer wet diapers than usual during this period. He appears dehydrated and is crying without tears. He is at the 50th percentile for length and 30th percentile for weight. He appears lethargic. His temperature is 38°C (100.4°F), pulse is 180/min, and blood pressure is 60/40 mm Hg. Examination shows sunken eyes, dry mucous membranes, and a sunken anterior fontanel. Arterial blood gas analysis on room air shows:
pH 7.2
PCO2 38 mm Hg
PO2 90 mm Hg

Which of the following is the most likely explanation for this patient's arterial blood gas findings?
O A) Excessive metabolic acid formation
O B) Impaired ventilation
O C) Increased chloride loss (àincrease HCO3 which is not the case here)
O D) Increased CO2 concentration in the extracellular fluid
0 E) Increased metabolic acid produced by the gastrointestinal tract

[ArchivalUser]

AA?

[ArchivalUser]

eee

We studied a group of patients with rotavirus diarrhea to determine the association of carbohydrate malabsorption during diarrhea with the degree of acidosis and severity of purging. Unlike enterotoxigenic diarrhea in which the metabolic acidosis is due to loss of bicarbonate in an alkaline stool, patients with rotavirus develop a metabolic acidosis while passing an acid stool with little detectable bicarbonate. Also unlike enterotoxigenic diarrhea, rotavirus stool contains large quantities of reducing substances suggesting significant carbohydrate malabsorption. Our findings are consistent with the hypothesis that carbohydrate malabsorption is an important secondary pathophysiological mechanism in the rotavirus diarrhea syndrome. This model for rotavirus diarrhea helps to explain the electrolyte and acid- base pattern of the rotavirus stool and stresses the importance of further nutrition balance studies to determine the optimal dietary management of patients with rotavirus diarrhea.

http://www.ajcn.org/cgi/content/abstract/36/6/1112

[ArchivalUser]

thanks showman this is a very interesting article

[ArchivalUser]

thank you showman

[ArchivalUser]

why not aaaa due to lactic acidosis

[ArchivalUser]

The ABG shows acidosis, the HCO3- value is not mentioned , but since PCO2 is normal the diagnosis is Metabolic Acidosis. Severe dehydration is evident and hypotension is also seen ! There is a history of diarrhea which can cause Metabolic acidosis with a Normal Anion gap. That means it causes Hyperchloremic acidosis. Since the patient is in hypovolemic shock , and low BP is seen -> Lactic acidosis. Which is a high AG acidosis. So in this case it has to excess acid that is Lactic acid production !