A medical student complains of severe vomiting and diarrhea for 2 days since eating at the Roadkill Café. His blood pressure is 120/70 mmHg supine and 90/50 mmHg standing. His skin and mucous membranes are dry. Which of the following laboratory finding would you expect to find?
A) Low serum aldosterone concentration
B) High atrial natriuretic peptide (ANP) levels
C) Low plasma renin activity
D) Low urinary sodium concentration
E) High urine volume

Question

Quizplus · Accepted Answer

The patient's symptoms of severe vomiting and diarrhea lead to significant fluid loss, resulting in dehydration. This dehydration causes the body to conserve water and sodium to maintain blood pressure and volume. Aldosterone, a hormone that promotes sodium (and thus water) reabsorption in the kidneys, would be elevated in response to the decreased blood volume and pressure, leading to a low urinary sodium concentration as the body tries to retain sodium to conserve water.

A Medical Student Complains of Severe Vomiting and Diarrhea for 2