Anorexia Nervosa

KEY FEATURES

Essentials of Diagnosis

• Restriction of energy intake leading to a significantly low body weight in the context of age, sex, developmental trajectory, and physical health

• Intense fear of gaining weight or behavior that prevents weight gain

• Distorted perception of body image, with undue influence of weight on self-worth

• Denial of the medical seriousness of underweight status

General Considerations

• Begins in the years between adolescence and young adulthood, but often persists into older adulthood

• Two subtypes

  • 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, fasting, or excessive exercising without associated binge-eating or purging

• Cause not known, probably of primary psychiatric origin; comorbidity with depression, anxiety, or obsessive-compulsive disorder is not uncommon

• Must exclude medical or psychiatric illnesses that can account for anorexia, weight loss

• Severity is classified according to body mass index (BMI)

  • Mild, BMI 17–18.49

  • Moderate, BMI 16–16.99

  • Severe, BMI 15–15.99

  • Extreme, BMI < 15

Demographics

• Previously was thought to impact mainly White females of middle to upper socioeconomic status

• Increasingly recognized in males, people of color, and transgender and gender nonconforming individuals

• 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 females of reproductive age, cessation of menstruation is common

• In severe cases, bradycardia, hypotension, and hypothermia

• Cold intolerance

• Constipation

• Amenorrhea

Differential Diagnosis

• Bulimia

• 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 central nervous system disorders (eg, hypothalamic tumor)

• Malignancy

• AIDS

• Substance abuse

DIAGNOSIS

• Diagnosis is based on energy restriction, distorted body image, significantly low body weight, fear of weight gain or loss of control over food intake, and refusal to exceed minimal healthy weight

• Exclusion of medical or psychiatric illnesses that can account for anorexia and weight loss

• 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 luteinizing hormone-releasing hormone

TREATMENT

Medications

• Tricyclic antidepressants, selective serotonin reuptake inhibitors, and lithium are effective in some cases

Therapeutic Procedures

• Treatment goal: restoration of healthy body weight and improvement in psychological comorbidities

• Supportive care

• Cognitive-behavioral therapy

• Intensive psychotherapy

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