Anorexia Nervosa

Primarily in white adolescent females from middle- or upper-class families; 4% to 10% males.

More common in models, ballet students, and professions demanding high achievement.

Occurs in 5-10 per 100,000 population; mortality rate 5-10%.

Bimodal peak age of onset: 14 and 18 y.

Predisposing conditions include:

• CV dysfunction (bradycardia, hypotension, and dysrhythmias).

• Acid-base abnormalities (both metabolic acidosis and alkalosis are possible), lyte abnormalities (decreased K, Mg, NA, and P)

• Hematologic abnormalities (decreased Hgb, WBC, fibrinogen, and plt).

• Hypothermia, delayed gastric emptying, and renal dysfunction (prerenal azotemia).

Lyte/nutrient abnormalities associated with refeeding: most dangerous is hypophosphatasia (but also thiamine deficiency and decreased K. Mg, NA, and P).

Degree and duration of malnutrition (excess protein depletion = impaired cellular function)

Degree of organ dysfunction

Greater weight loss = greater risk

Refeeding syndrome (severe hypophosphatasia occurred in 0.5% in largest modern study)

Anorexia nervosa

• Obsessive fear of obesity; pursuit of thinness

• Dramatic decrease in food intake and excessive physical activity

• Refusal to maintain weight above 85% IBW

• Distorted body image

• Amenorrhea for >3 mo

• Radical restriction of caloric intake

• Appears cachectic

• Risk of death high if weight loss >40% of IBW

• Of patients, 40% to 50% recover with treatment; 20% to 30% improve with treatment

Bulimia

• Means “ox hunger” or voracious appetite

• Obsessive fear of obesity; overconcern with body shape and weight

• Appears well nourished

• Averages two binge-eating episodes each wk for at least 3 mo

• Irresistible urge to overeat; loss of control in desire to eat

• Wt control by self-induced vomiting, diuretic and laxative use, strict dieting/fasting, vigorous exercise

• Greater percent of alcohol use, illicit drug use, stealing, self-mutilation, and suicide attempts than with anorexia

• Of patients, 30% to 60% recover with treatment