Chapter 076. Eating Disorders (Part 6) Table 76-3 Diagnostic Features of Bulimia Nervosa Recurrent episodes of binge eating, which is characterized by the consumption of a large amount of food in a short period of time and a feeling that the eating is out of control. Recurrent inappropriate behavior to compensate for the binge eating, such as self-induced vomiting. The occurrence of both the binge eating and the inappropriate compensatory behavior at least twice weekly, on average, for 3 months. Overconcern with body shape and weight. Note: If the diagnostic criteria for anorexia nervosa are simultaneously met, only the diagnosis of anorexia nervosa is given The physical abnormalities associated with BN primarily result from the purging behavior. Painless bilateral salivary gland hypertrophy (sialadenosis) may be noted. A scar or callus on the dorsum of the hand may develop due to repeated trauma from the teeth among patients who manually stimulate the gag reflex. Recurrent vomiting and the exposure of the lingual surfaces of the teeth to stomach acid lead to loss of dental enamel and eventually to chipping and erosion of the front teeth. Laboratory abnormalities are surprisingly infrequent, but hypokalemia, hypochloremia, and hyponatremia are observed occasionally. Repeated vomiting may lead to alkalosis, whereas repeated laxative abuse may produce a mild metabolic acidosis. Serum amylase may be slightly elevated due to an increase in the salivary isoenzyme. Serious physical complications resulting from BN are rare. Oligomenorrhea and amenorrhea are more frequent than among women without eating disorders. Arrhythmias occasionally occur secondary to electrolyte disturbances. Tearing of the esophagus and rupture of the stomach have been reported and constitute life- threatening events. Some patients who chronically abuse laxatives or diuretics develop transient peripheral edema when this behavior ceases, presumably due to high levels of aldosterone secondary to persistent fluid and electrolyte depletion. Diagnosis The critical diagnostic features of BN are repeated episodes of binge eating followed by inappropriate and abnormal behaviors aimed at avoiding weight gain (Table 76-3). The diagnosis of BN requires a candid history from the patient detailing frequent, large eating binges followed by the purposeful use of inappropriate mechanisms to avoid weight gain. Most patients with BN who present for treatment are distressed by their inability to control their eating behavior but are able to provide such details if queried in a supportive and nonjudgmental fashion. As in AN, there are two subtypes of BN. Patients with the "purging" subtype utilize compensatory behaviors that directly rid the body of calories or fluids (e.g., self-induced vomiting, laxative, or diuretic abuse), whereas those with the "nonpurging" subtype attempt to compensate for binges by fasting or by excessive exercise. Patients with the nonpurging subtype tend to be heavier and are less prone to fluid and electrolyte disturbances. Prognosis The prognosis of BN is much more favorable than that of AN. Mortality is low, and full recovery occurs in approximately 50% of patients within 10 years. Approximately 25% of patients have persistent symptoms of BN over many years. Few patients progress from BN to AN. Bulimia Nervosa: Treatment BN can usually be treated on an outpatient basis (Fig. 76-1). Cognitive behavioral therapy (CBT) is a short-term (4–6 months) psychological treatment that focuses on the intense concern with shape and weight, the persistent dieting, and the binge eating and purging that characterize this disorder. Patients are directed to monitor the circumstances, thoughts, and emotions associated with binge/purge episodes, to eat regularly, and to challenge their assumptions linking weight to self-esteem. CBT produces symptomatic remission in 25–50% of patients. Numerous double-blind, placebo-controlled trials have documented that antidepressant medications are useful in the treatment of BN but are probably somewhat less effective than CBT. Although efficacy has been established for virtually all chemical classes of antidepressants, only the selective serotonin reuptake inhibitor fluoxetine (Prozac) has been approved for use in BN by the U.S. Food and Drug Administration. Antidepressant medications are helpful even for patients with BN who are not depressed, and the dose of fluoxetine recommended for BN (60 mg/d) is higher than that typically used to treat depression. These observations suggest that different mechanisms may underlie the utility of these medications in BN and in depression. A subset of patients does not respond to CBT, antidepressant medication, or their combination. More intensive forms of treatment, including hospitalization, may be required. Further Readings American Psychiatri c Association: Practice guidelines for the treatment of patients with eating disorders, third edition. Am J Psychiatry, 2006 Chan JL, Mantzoros CS: Role of leptin in energy- deprivation states: Normal human physiology and clinical implications for hypotha lamic amenorrhoea and anorexia nervosa. Lancet 366:74, 2005 [PMID: 15993236] Katzman DK: Medical complications in adolescents with anorexia: A review of the literature. Int J Eat Disord 37(Suppl):S52, 2005 Keski-Rahkonen A et al: Epidemiology and cours e of anorexia nervosa in the community. Am J Psychiatry 164(8):1259, 2007 [PMID: 17671290] Klein DA, Walsh BT: Eating disorders: Clinical features and pathophysiology. Physiol Behav 81:359, 2004 [PMID: 15159176] Mehler PS: Clinical practice. Bulimia ne rvosa. N Engl J Med 349:875, 2003 [PMID: 12944574] Sysko R, Walsh BT: A critical evaluation of the efficacy of self- help interventions for the treatment of bulimia nervosa and binge- eating disorder. Int J Eat Disord Oct 5 2007, epub ahead of print Yage r J, Andersen AE: Clinical practice. Anorexia nervosa. N Engl J Med 353:1481, 2005 [PMID: 16207850] . Chapter 076. Eating Disorders (Part 6) Table 76-3 Diagnostic Features of Bulimia Nervosa Recurrent episodes of binge eating, which is characterized by the. feeling that the eating is out of control. Recurrent inappropriate behavior to compensate for the binge eating, such as self-induced vomiting. The occurrence of both the binge eating and the. from BN are rare. Oligomenorrhea and amenorrhea are more frequent than among women without eating disorders. Arrhythmias occasionally occur secondary to electrolyte disturbances. Tearing of