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For further information, see CMDT Part 29-05: Anorexia Nervosa

Key Features

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

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

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

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

Complications

  • Poor dentition

  • Pharyngitis

  • Esophagitis

  • Aspiration

  • Gastric dilatation

  • Pancreatitis

  • Constipation

  • Hemorrhoids

  • Dehydration

  • Electrolyte abnormalities

Prognosis

  • 50% of ...

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