Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 29-05: Anorexia Nervosa + Key Features Download Section PDF Listen +++ +++ Essentials of Diagnosis ++ Restriction of calorie intake, leading to underweight BMI (BMI < 18.5) Intense fear of gaining weight or behavior that prevents weight gain despite underweight BMI Distorted perception of body image, with undue influence of weight on self-worth Denial of the medical seriousness of underweight status +++ General Considerations ++ Characterized by underweight BMI, intense fear of gaining weight and distorted perception of body image Begins in the years between adolescence and young adulthood Cause not known, probably of primary psychiatric origin Must exclude medical or psychiatric illnesses that can account for anorexia, weight loss The American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) classifies the severity of anorexia according to BMI: Mild: BMI 17–18.49 Moderate: BMI 16–16.99 Severe: BMI 15–15.99 Extreme: BMI < 15 DSM–5 defines two subtypes of anorexia nervosa Binge-eating/purging type is characterized by recurrent episodes of binge-eating or purging (ie, self-induced vomiting and/or abuse of diuretics, laxatives, enemas, cathartics) Restricting type is characterized by dieting, fasting or excessive exercising without associated binge-eating or purging +++ Demographics ++ Occurs most commonly in females (90%), predominantly middle and upper income Estimated prevalence 270 cases per 100,000 population for females 22 cases per 100,000 population for males + Clinical Findings Download Section PDF Listen +++ +++ Symptoms and Signs ++ Loss of body fat with severe emaciation Dry and scaly skin Increased lanugo body hair Parotid enlargement and edema In severe cases, bradycardia, hypotension, and hypothermia Cold intolerance Constipation Amenorrhea +++ Differential Diagnosis ++ Bulimia nervosa, binge eating disorder Endocrine and metabolic disorders Panhypopituitarism Addison disease Hyperthyroidism Diabetes mellitus Gastrointestinal disorders Malabsorption Pancreatic insufficiency Crohn disease Gluten enteropathy Chronic infections, eg, tuberculosis Cancer, eg, lymphoma Rare CNS disorders, eg, hypothalamic tumor Severe malnutrition Depression Obsessive-compulsive disorder Body dysmorphic disorder Malignancy AIDS Substance abuse + Diagnosis Download Section PDF Listen +++ +++ Laboratory Tests ++ Check for anemia, leukopenia, electrolyte abnormalities, and elevations of blood urea nitrogen and serum creatinine Serum cholesterol level often increased Luteinizing hormone level depressed and impaired response to gonadotropin-releasing hormone + Treatment Download Section PDF Listen +++ +++ Medications ++ Tricyclic antidepressants, selective serotonin reuptake inhibitors, and lithium carbonate are effective in some cases +++ Therapeutic Procedures ++ Treatment goal: restoration of normal body weight and improvement in psychological difficulties Therapeutic modalities Supportive care Structured behavioral therapy Intensive psychotherapy Family therapy Hospitalization may be necessary Treatment by experienced teams successful in about two-thirds of cases + Outcome Download Section PDF Listen +++ +++ Complications ++ Poor dentition Pharyngitis Esophagitis Aspiration Gastric dilatation Pancreatitis Constipation Hemorrhoids Dehydration Electrolyte abnormalities +++ Prognosis ++ 50% of patients continue to experience difficulties with eating behavior and psychiatric problems 2–6% of patients die of the complications of the disorder or from suicide +++ When to Refer ++ Adolescents and young adults with otherwise unexplained weight loss should be evaluated by a psychiatrist All patients with diagnosed anorexia nervosa should be co-managed with a psychiatrist +++ When to Admit ++ Signs of hypovolemia, major electrolyte disorders, and severe protein-energy malnutrition Failure to improve with outpatient management + References Download Section PDF Listen +++ + +Crow SJ. Pharmacologic treatment of eating disorders. Psychiatr Clin North Am. 2019 Jun;42(2):253–62. [PubMed: 31046927] + +Fazeli PK et al. Effects of anorexia nervosa on bone metabolism. Endocr Rev. 2018 Dec 1;39(6):895–910. [PubMed: 30165608] + +Franko DL et al. Predictors of long-term recovery in anorexia nervosa and bulimia nervosa: data from a 22-year longitudinal study. J Psychiatr Res. 2018 Jan;96:183–8. [PubMed: 29078155] + +Himmerich H et al. Psychopharmacological advances in eating disorders. Expert Rev Clin Pharmacol. 2018 Jan;11(1):95–108. [PubMed: 28933969] + +Khalsa SS et al. What happens after treatment? A systematic review of relapse, remission, and recovery in anorexia nervosa. J Eat Disord. 2017 Jun 14;5:20. [PubMed: 28630708] + +Lock J. Updates on treatments for adolescent anorexia nervosa. Child Adolesc Psychiatr Clin N Am. 2019 Oct;28(4):523–35. [PubMed: 31443871] + +Resmark G et al. Treatment of anorexia nervosa—new evidence-based guidelines. 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