Anorexia Nervosa

KEY FEATURES

Essentials of Diagnosis

• Restriction of calorie intake leading to underweight body mass index (BMI) (BMI < 18.5)

• 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

• Two subtypes: binge-eating/purging type and restricting type

• 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 BMI

  • Mild, BMI 17–18.49

  • Moderate, BMI 16–16.99

  • Severe, BMI 15–15.99

  • Extreme, BMI < 15

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 females of reproductive age, cessation of menstruation is common

• In severe cases, bradycardia, hypotension, and hypothermia

• Cold intolerance

• Constipation

• Amenorrhea

Differential Diagnosis

• 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)

• Severe malnutrition

• Depression

• Obsessive-compulsive disorder

• Body dysmorphic disorder

• Malignancy

• AIDS

• Substance abuse

DIAGNOSIS

• 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 normal body weight and improvement in psychological comorbidities

• 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 patients continue to experience difficulties with underweight, eating behaviors, 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 ...