INTRODUCTION AND DEFINITION
Weight gain is the cornerstone of treatment for patients with anorexia nervosa (AN) [1,2]. However, serious and potentially fatal complications can arise when refeeding patients with AN. The refeeding syndrome is defined as the clinical complications that occur as a result of fluid and electrolyte shifts during nutritional rehabilitation of malnourished patients . Patients who weigh less than 70 percent of ideal body weight or lose weight rapidly are at greatest risk for the syndrome. One case series reported an incidence of six percent in adolescents hospitalized for treatment of AN .
Patients other than those with AN are at risk for the refeeding syndrome . These include oncology patients undergoing chemotherapy, malnourished elderly patients, certain postoperative patients, and homeless or alcoholic patients who have not eaten for many days.
The refeeding syndrome in AN and its management are reviewed here. The evaluation for medical complications and criteria for hospitalization of patients with AN; medical complications of AN and their management; epidemiology, pathogenesis, clinical features, treatment, and outcome of AN; and the medical complications of bulimia nervosa and binge eating disorder are discussed separately.
DIAGNOSIS OF ANOREXIA NERVOSA
Patients with anorexia nervosa (AN) are unable to maintain a minimally normal body weight of at least 85 percent of that expected for age and height . AN is also characterized by intense fear of gaining weight and a disturbed perception of body weight and shape (table 1).