Anorexia Nervosa

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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

Physical effects of anorexia nervosa

  • 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). Anorexia Nervosa: Organ System Complications

⭐ 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.

Practice Questions: Anorexia Nervosa

Test your understanding with these related questions

Which of the following is FALSE regarding Anorexia Nervosa:

1 of 5

Flashcards: Anorexia Nervosa

1/9

_____ is the first-line pharmacological treatment for Bulimia nervosa.

TAP TO REVEAL ANSWER

_____ is the first-line pharmacological treatment for Bulimia nervosa.

Fluoxetine

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