Which electrolyte abnormality is commonly seen in bulimia nervosa due to vomiting?

• A. Hyperkalemia
• B. Hypomagnesemia
• C. Hypokalemia
• D. Hypercalcemia

Answer: (C)

Vomiting from bulimia commonly causes a loss of stomach acid and fluids, which drives a metabolic alkalosis. As the body responds to volume depletion from this fluid loss, the renin-angiotensin-aldosterone system is activated, promoting potassium loss in the kidneys. The combination of direct potassium loss in emesis and renal potassium wasting under aldosterone influence leads to low potassium levels in the blood.

Low potassium (hypokalemia) is the classic electrolyte abnormality in this scenario, and it can lead to symptoms like muscle weakness and, more concerning, arrhythmias. Other choices don’t fit the typical pattern: vomiting most strongly creates potassium loss and alkalosis rather than high potassium, high calcium, or consistent hypomagnesemia in this context.