[Anorexia nervosa and bulimia nervosa. IIi. Somatic complications of purging].

Patients with anorexia nervosa or bulimia nervosa may try to compensate weight gain due to binge eating by purging: vomiting or use of diuretics, laxatives or diet pills. Purging may reduce the body weight through volume depletion, but has hardly any effect on the food uptake. Frequent vomiting is revealed by enlargement of the submandibular and parotid glands and rise of the serum amylase. Use of laxatives leads to electrolyte imbalances, lesions of intestinal mucosa and chronic obstipation. Physical effects of diuretics are dehydration and electrolyte imbalance; oedema may be a sign of their discontinuation. Frequent or major effects of purging are: disorders of cardiac conduction (caused by hypokalaemia), insults and cerebral dysfunction (both due to hyponatraemia). A normal serum potassium concentration does not exclude intracellular hypokalaemia; accordingly, electrocardiography is indicated.