Which electrolyte abnormality is specifically associated with purging-type anorexia?

Which electrolyte abnormality is specifically associated with purging-type anorexia?

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

Answer: (A)

Vomiting removes stomach acid (hydrochloric acid), which carries both hydrogen ions and chloride. Losing H+ raises the blood pH, producing metabolic alkalosis, while losing chloride leads to low serum chloride (hypochloremia). This combination—metabolic alkalosis with hypochloremia—is characteristic of purging-type eating disorders. High chloride wouldn’t fit because chloride is lost with vomiting. Low bicarbonate would imply acidosis, not alkalosis; whereas bicarbonate often rises in this scenario due to the alkaline state, though the most specific finding tied to purging is the low chloride.

Vomiting removes stomach acid (hydrochloric acid), which carries both hydrogen ions and chloride. Losing H+ raises the blood pH, producing metabolic alkalosis, while losing chloride leads to low serum chloride (hypochloremia). This combination—metabolic alkalosis with hypochloremia—is characteristic of purging-type eating disorders.

High chloride wouldn’t fit because chloride is lost with vomiting. Low bicarbonate would imply acidosis, not alkalosis; whereas bicarbonate often rises in this scenario due to the alkaline state, though the most specific finding tied to purging is the low chloride.