Renal and electrolyte complications in eating disorders: a comprehensive review

Eating disorders are psychiatric disorders with significant and widespread medical complications, including renal disorders. Renal disease is not uncommon in patients with eating disorders but is often unrecognized. It includes both acute renal injury and progression to chronic kidney disease requiring dialysis. Electrolyte abnormalities including hyponatremia, hypokalemia, and metabolic alkalosis are common in eating disorders and vary depending on whether patients engage in purging behaviors. Chronic hypokalemia due to purging in patients with anorexia nervosa-binge purge subtype or bulimia nervosa can lead to hypokalemic nephropathy and chronic kidney disease. Additional electrolyte derangements are seen during refeeding, including hypophosphatemia, hypokalemia, and hypomagnesemia. Patients can also develop Pseudo-Bartter's syndrome which leads to edema and rapid weight gain in patients who cease purging behavior. Clinicians and patients should be aware of these complications in order to provide education and early detection and prevention.