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:

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  CV dysfunction (bradycardia, hypotension, and dysrhythmias).

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

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

  
  
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  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).

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

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  Obsessive fear of obesity; pursuit of thinness

  
  
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  Dramatic decrease in food intake and excessive physical activity

  
  
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  Refusal to maintain weight above 85% IBW

  
  
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  Distorted body image

  
  
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  Amenorrhea for >3 mo

  
  
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  Radical restriction of caloric intake

  
  
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  Appears cachectic

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

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

Bulimia

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  Means “ox hunger” or voracious appetite

  
  
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  Obsessive fear of obesity; overconcern with body shape and weight

  
  
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  Appears well nourished

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

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

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

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

  
  
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  Of patients, 30% to 60% recover with treatment