Anorexia Nervosa
An eating disorder where a person dangerously restricts their food intake due to an intense fear of gaining weight and a distorted view of their own body.
Emergency Management: Medical instability requiring inpatient stabilization (severe bradycardia, syncope, severe electrolyte derangements).
A severe psychiatric illness characterized by an intense fear of gaining weight, a distorted body image, and restriction of energy intake leading to a significantly low body weight.
Detailed Overview
It has one of the highest mortality rates of any psychiatric disorder due to medical complications of starvation or suicide. Patients relentlessly pursue thinness despite profound emaciation. It is divided into restricting and binge-eating/purging subtypes.
Epidemiology & Demographics
Lifetime prevalence of ~0.9% in women and ~0.3% in men. Peak onset is during adolescence (15-19 years).
Etiological Mechanism
Multifactorial: genetic vulnerability (heritability 50-60%), neurobiological alterations in serotonin/dopamine pathways, and sociocultural pressures regarding thinness.
Primary Causes
Complex interplay of genetics, perfectionistic personality traits, and environmental stressors.
Chronic starvation state downregulates the hypothalamic-pituitary-gonadal/thyroid axes, causing amenorrhea and sick euthyroid syndrome. Brain imaging shows reduced gray matter and altered reward circuitry (striatum) response to food, where fasting becomes anxiolytic (reduces anxiety) and eating induces severe anxiety.
Diagnostic Criteria & Guidelines
DSM-5: 1) Restriction of energy intake relative to requirements, leading to a significantly low body weight. 2) Intense fear of gaining weight or becoming fat. 3) Disturbance in the way one's body weight or shape is experienced.
Nutritional Rehabilitation (primary intervention) to restore weight to at least 90% of ideal. Psychotherapy: Family-Based Treatment (FBT or Maudsley method) is the gold standard for adolescents. Cognitive Behavioral Therapy for Eating Disorders (CBT-E) for adults.
Second-Line & Adjunctive Therapy
Pharmacotherapy is generally ineffective for the core symptoms of anorexia. SSRIs (e.g., Fluoxetine 20-60 mg/day) may be used to treat co-occurring depression/OCD only AFTER weight has been substantially restored (ineffective in starvation state). Olanzapine 2.5-5 mg may help with severe weight-gain anxiety.
Surgical & Procedural Management
None. In severe, life-threatening cases refusing oral intake, involuntary nasogastric (NG) tube feeding is indicated.
Patient Counseling & Advice
Counsel the family that recovery is a marathon (often 3-5 years) and involves frequent relapses. Emphasize that the eating disorder is a severe illness, not a lifestyle choice.
Follow-Up & Monitoring Schedule
Weekly weights (blinded to patient). Regular monitoring of electrolytes, particularly phosphorus, magnesium, and potassium during early refeeding to prevent Refeeding Syndrome.
Preventive Strategies
Promoting healthy body image and preventing diet culture messaging in youth.
Guarded. ~50% recover fully, ~30% have partial recovery/chronic relapses, and ~20% remain chronically ill. Mortality rate is ~5-10% per decade of illness.