Eating Disorders: Anorexia Nervosa And Bulimia


Introduction

  • Description: Anorexia nervosa is a syndrome characterized by an altered body image, significant weight loss, and amenorrhea that are not caused by physical disease. Bulimia is an eating disorder characterized by an altered body image and recurrent binge eating, with or without purging, through self-induced vomiting, laxative abuse, or diuretics. Exercise excess is often a part of after-binge behavior. Both affect more women than men.

  • Prevalence: Females, 1%–3%; 3-fold greater prevalence in women than in men. Subclinical eating disorders are common in university populations.

  • Predominant Age: Teens to early 20s, median onset at 18 years of age.

  • Genetics: A study of Finnish twins found a higher lifetime prevalence of 2.2% vs. a background rate of 0.3%–1.0%. A locus on chromosome 12 (rs4622308) has been associated with anorexia nervosa.

Etiology and Pathogenesis

  • Causes: Unknown (emotional). Abnormal functioning of corticolimbic circuits involved in appetite may contribute to anorexia nervosa. Deficits have been found in dopaminergic function (dopamine is considered to be involved with eating behavior, motivation, and reward) and serotonergic function (serotonin may be involved with mood, impulse control, and obsessional behavior).

  • Risk Factors: Anorexia nervosa—perfectionistic personality (high expectations, personal, or external). Bulimia—impulsive character, low self-esteem, stress (eg, multiple responsibilities, tight schedules), early puberty. At high risk for both: dancers, models, cheerleaders, and athletes.

Signs and Symptoms

  • Insidious onset (occasionally stress related)

  • Significant weight loss (15% below expected weight, average body mass index = 16 kg/m 2 )

  • Denial of problem

  • Preoccupation with weight or body image

  • Anorexia nervosa—impression of obesity rather than objective view of weight

  • Reduced food intake or refusal (often associated with elaborate eating rituals)

  • Intense fear of gaining weight

  • Excessive exercise (marathon running)

  • Bulimia—high-calorie binges followed by severe restriction

  • Food collections or hoarding

  • Medication abuse (laxatives, diuretics, ipecac, thyroid medication)

  • Dental erosion and scarred knuckles (secondary to finger-induced vomiting)

  • Amenorrhea is common but not required for the diagnosis

Diagnostic Approach

Differential Diagnosis

  • Wasting disease (tumors)

  • Depression

  • Hypothalamic tumor

  • Food phobia

  • Gastrointestinal disease

  • Other emotional disorders (conversion disorder, schizophrenia, body dysmorphic disorder)

  • Associated Conditions: Major depressive disorder (50%–75% of patients), obsessive–compulsive disorders (10%–13%), bipolar disorder, attention deficit hyperactivity disorder (20%), alcohol use disorder (20%), sexual disinterest, growth arrest, hypotension and bradycardia, myocardial atrophy or fibrosis, mitral valve prolapse, gastroparesis, constipation, hypothermia, and peripheral edema. Prolonged amenorrhea is associated with an increased risk of osteoporosis, which may not be reversible. Bulimia—social phobia and anxiety disorders, substance abuse, and shoplifting are common.

You're Reading a Preview

Become a Clinical Tree membership for Full access and enjoy Unlimited articles

Become membership

If you are a member. Log in here