Eating Disorders

Eating Disorders - Defining the Demons

• Core: Persistent disturbed eating/behavior → altered food intake/absorption → significant health/psychosocial impairment.
• Major Types (DSM-5):
  • Anorexia Nervosa (AN): Intense fear of weight gain, distorted body image, severe restriction. BMI often < 17.5.
  • Bulimia Nervosa (BN): Recurrent binges + compensatory behaviors (e.g., purging). Min. 1x/wk for 3mo.
  • Binge Eating Disorder (BED): Recurrent binges, distress, NO regular compensatory behaviors. Min. 1x/wk for 3mo.
  • ARFID: Restrictive intake (not body image driven) → nutritional deficiency.
  • Pica: Eating non-nutritive, non-food items.
  • Rumination Disorder: Repeated food regurgitation.

⭐ Anorexia Nervosa (AN) has the highest mortality rate among psychiatric disorders.

Anorexia Nervosa - Starvation's Grip

• Intense fear of weight gain, distorted body image, significantly low body weight.
• Types: Restricting; Binge-eating/purging.
• Key Features: Amenorrhea, bradycardia (< 50 bpm), hypotension, hypothermia (< 35°C), lanugo, hair loss, dry skin, osteoporosis, muscle wasting, constipation.
• Endocrine: ↓LH, ↓FSH, ↓estrogen/testosterone, ↑cortisol, sick euthyroid.
• Electrolytes: ↓K⁺, ↓PO₄³⁻, ↓Mg²⁺ (esp. during refeeding).
• Severity (Adult BMI $kg/m^2$, where $BMI = \frac{weight (kg)}{height (m)^2}$): Mild (≥ 17), Moderate (16-16.99), Severe (15-15.99), Extreme (< 15).
• ⚠️ Critical: Refeeding syndrome (can be fatal; monitor PO₄³⁻). Cardiac complications (arrhythmias, sudden death).

⭐ Anorexia Nervosa has the highest mortality rate among psychiatric disorders.

Bulimia & Binge - Cycle Unmasked

Bulimia Nervosa (BN):

• Recurrent binge eating (large food amount, loss of control).
• Recurrent inappropriate compensatory behaviors (purging, laxatives, fasting, excessive exercise).
• Frequency: ≥1x/week for 3 months.
• Self-worth significantly tied to body shape/weight.
• Signs: Russell's sign (knuckle calluses), dental erosion, parotid gland hypertrophy, hypokalemia (↓K+).

Binge Eating Disorder (BED):

• Recurrent binge eating episodes with marked distress.
• Associated with ≥3 of: eating rapidly; eating until uncomfortably full; eating large amounts when not physically hungry; eating alone due to embarrassment; feeling disgusted, depressed, or very guilty afterward.
• Frequency: ≥1x/week for 3 months.
• NO recurrent inappropriate compensatory behaviors.

⭐ Hypokalemia (serum K+ < 3.5 mEq/L) is a critical complication in Bulimia Nervosa due to purging behaviors (e.g., vomiting, laxative abuse), potentially leading to life-threatening cardiac arrhythmias.

Treatment Toolkit - Healing Paths

• Multidisciplinary Team (MDT): Essential (Psychiatrist, Physician, Dietitian, Therapist).
• Nutritional Rehabilitation:
  • Goal: Weight gain 0.5-1 kg/week (outpatient), 1-2 kg/week (inpatient).
  • ⚠️ Refeeding Syndrome: Risk if <70% Ideal Body Weight (IBW) or rapid refeed. Monitor $K^+$, $PO_4^{3-}$, $Mg^{2+}$. Start low, go slow. Thiamine supplementation crucial before feeding.
• Psychotherapy:
  • Anorexia Nervosa (AN): Family-Based Therapy (FBT) is gold standard for adolescents. Cognitive Behavioral Therapy-Enhanced (CBT-E).
  • Bulimia Nervosa (BN) & Binge Eating Disorder (BED): CBT-E (first-line), Interpersonal Therapy (IPT).
• Pharmacotherapy:
  • Fluoxetine for BN/BED (often after weight restoration if comorbid AN).
  • Olanzapine for AN (adjunctive for weight gain, reducing agitation).
• Hospitalization Criteria: Medically unstable (e.g., HR <40/min, BP <80/60 mmHg, Temp <35°C, <75% IBW, significant electrolyte imbalance), acute psychiatric risk (e.g., suicidal ideation).

⭐ Family-Based Therapy (FBT) is the leading evidence-based treatment for adolescents with Anorexia Nervosa, emphasizing parental involvement in nutritional restoration and weight gain at home.

High‑Yield Points - ⚡ Biggest Takeaways

• Anorexia Nervosa (AN): BMI < 18.5, intense fear of weight gain, distorted body image, amenorrhea.
• Bulimia Nervosa (BN): Recurrent binge eating with compensatory behaviors. Russell's sign; normal/overweight.
• Binge Eating Disorder (BED): Recurrent binge eating without compensatory behaviors; causes distress.
• Complications: AN - osteoporosis, bradycardia; BN - hypokalemia, dental erosion.
• Refeeding Syndrome: Risk in AN re-nutrition, monitor hypophosphatemia.
• Management: Psychotherapy (CBT, FBT) is core. SSRIs for BN/BED. Use SCOFF for screening.