A patient with severe diarrhea has a serum bicarbonate level of 18 mEq/L. What is the most likely cause of this patient's metabolic acidosis?

A Loss of bicarbonate ions in the stool ✓
B Increased production of ketoacids
C Lactic acidosis due to tissue hypoxia
D Renal failure with inability to excrete hydrogen ions

Explanation

Severe diarrhea can lead to significant loss of bicarbonate ions in the stool, resulting in metabolic acidosis.

Source

Harrison's Principles of Internal Medicine
Electrolytes and Acid-Base Balance Pathophysiology Gastrointestinal Disorders Hard MEDICAL Confidence: medium