Anorexia Nervosa

Intro & Epi - Skinny on Anorexia

• Definition: Persistent energy restriction → significantly low body weight (BMI < 18.5 kg/m² or <85% expected); intense fear of weight gain; body image distortion.
• Subtypes (behavior in last 3 months):
  • Restricting: Fasting, dieting, excessive exercise. No recurrent binge/purge.
  • Binge-eating/purging: Recurrent binge eating OR purging (e.g., vomiting, laxatives).
• Epidemiology:
  • Prevalence: ~0.5-1%; F:M ~10:1.
  • Onset: Mid-adolescence (14-18 yrs).

⭐ Highest mortality rate of all psychiatric disorders (medical complications/suicide).

Clinical Picture - Wasting Away Woes

• Psychological Core:
  • Intense fear of gaining weight or becoming fat.
  • Distorted body image (perceives self as overweight despite emaciation).
  • Preoccupation with food, calories, weight.
• Behavioral Manifestations:
  • Severe food restriction (↓ caloric intake).
  • Excessive, compulsive exercise.
  • Possible purging (vomiting, laxatives, diuretics).
  • Food rituals, social withdrawal.
• Physical Sequelae (Starvation Effects):
  • Low BMI (< 18.5 kg/m²; severe < 17 kg/m²).
  • Amenorrhea, lanugo hair, hair loss.
  • Bradycardia, hypotension, hypothermia.
  • Constipation, cold intolerance, dry skin.
  • Osteoporosis, electrolyte imbalances ($↓K⁺$ if purging).

⭐ Russell's sign (knuckle calluses) may indicate self-induced vomiting in purging subtype.

Diagnosis Decoded - The Anorexia Algorithm

• Core DSM-5 Criteria (ABC):
  • A: Persistent restriction of energy intake leading to significantly low body weight (contextualized by age, sex, development, physical health).
  • B: Intense fear of gaining weight or becoming fat, OR persistent behavior that interferes with weight gain, despite low weight.
  • C: Disturbance in experiencing one's body weight/shape, undue influence of weight/shape on self-evaluation, OR persistent denial of current low weight's seriousness.

• Severity (Adults, BMI kg/m²):
  • Mild: BMI ≥ 17
  • Moderate: BMI 16-16.99
  • Severe: BMI 15-15.99
  • Extreme: BMI < 15

⭐ Amenorrhea, previously a DSM-IV criterion, is NOT required for Anorexia Nervosa diagnosis in DSM-5.

Danger Signals - Anorexia's Aftermath

• Cardiovascular: Bradycardia (<60 bpm), hypotension, arrhythmias (prolonged QTc), mitral valve prolapse.
• Endocrine: Amenorrhea, osteoporosis (↓estrogen, ↑cortisol), euthyroid sick syndrome.
• Hematological: Pancytopenia (leukopenia, anemia).
• Metabolic: Hypokalemia, hypophosphatemia, hypomagnesemia (refeeding syndrome risk ⚠️).
• GI: Gastroparesis, constipation, ↑LFTs.
• Dermatological: Lanugo hair, xerosis (dry skin), carotenemia.
• Comorbidities: Depression, anxiety disorders (OCD, social phobia).

⭐ Osteoporosis is a severe, often irreversible complication due to chronic hypoestrogenism and malnutrition.

Treatment Trek - Road to Recovery

• Foundation: Multidisciplinary Team (MDT) - psychiatrist, physician, dietitian, therapist.
• Nutritional Rehabilitation:
  • Goal: Gradual weight restoration (0.5-1 kg/wk inpatient; 0.2-0.5 kg/wk outpatient).
  • ⚠️ Critical: Monitor Refeeding Syndrome (hypophosphatemia, K, Mg).
• Psychotherapy:
  • Adults: CBT-E (Enhanced Cognitive Behavioural Therapy) - first-line.
  • Adolescents: Family-Based Treatment (FBT/Maudsley) - preferred.
• Pharmacotherapy (Adjunctive):
  • Olanzapine: May aid weight gain, reduce anxiety/obsessionality.
  • SSRIs: For comorbidities post-weight restoration, not core AN.
• Prognosis: Early intervention & weight restoration improve outcomes.

⭐ Anorexia Nervosa has the highest mortality rate of psychiatric disorders, due to medical complications or suicide.

High-Yield Points - ⚡ Biggest Takeaways

• Core features: Intense fear of weight gain, distorted body image, and significantly low body weight (e.g., BMI < 18.5 kg/m²).
• Two subtypes: Restricting type and Binge-eating/purging type.
• Medical complications are common and severe: amenorrhea, bradycardia, osteoporosis, lanugo, and electrolyte imbalances (especially hypokalemia with purging).
• Has the highest mortality rate of all psychiatric disorders, often due to medical issues or suicide.
• Treatment cornerstone: Nutritional rehabilitation and psychotherapy (CBT, Family-Based Therapy). Olanzapine may aid weight gain.
• Key distinction from Bulimia Nervosa: significantly low body weight is present in Anorexia Nervosa.