Which of the following is a plausible electrolyte abnormality in purging-type anorexia?

• A. Low chloride
• B. Normal chloride
• C. High chloride
• D. Low bicarbonate

Answer: (A)

Purging-type anorexia commonly causes hypochloremic metabolic alkalosis from repeated vomiting of gastric contents that are rich in HCl. Losing chloride and hydrogen ions lowers serum chloride and shifts the body toward a higher bicarbonate level, producing metabolic alkalosis. Volume depletion from vomiting also stimulates aldosterone, which promotes further hydrogen and potassium losses, reinforcing the alkalosis and the low chloride state. So, low chloride fits the classic pattern seen in purging behaviors. High chloride would not match the loss of gastric chloride; low bicarbonate would contradict the alkalosis; a normal chloride would miss the characteristic electrolyte disturbance.