Anorexia and Bulimia: Etiology, Medical Complications, and Treatment

Eating disorders arise from a complex interplay of genetic, psychological, sociocultural, and environmental factors. Anorexia nervosa (AN) and bulimia nervosa (BN) are the most prevalent, but OSFED, ARFID, and binge‑eating disorder share overlapping features.

Multifactorial Etiology

• Genetic: Heritability 40–60%; GWAS implicate metabolic/psychiatric loci.
• Psychological: Perfectionism, cognitive rigidity, low self‑esteem, high harm avoidance.
• Trauma/Adversity: Childhood abuse, bullying, weight stigma.
• Sociocultural: Thin‑ideal internalization, social media comparison, diet culture.
• Neurobiological: Altered dopamine/serotonin signaling, hypothalamic‑pituitary dysregulation.

Diagnostic Hallmarks

• AN: Energy restriction → significantly low weight; intense fear of weight gain; body image disturbance. Subtypes: restricting vs. binge‑eating/purging.
• BN: Recurrent binge episodes (loss of control, large amount) + compensatory behaviors (vomiting, laxatives, fasting, exercise) ≥1×/week ×3 months; self‑evaluation unduly influenced by shape/weight.

Medical Sequelae (Systemic)

System	Complications
Cardiovascular	Bradycardia, hypotension, QT prolongation, arrhythmia, cardiomyopathy, sudden death
Endocrine	Hypogonadotropic hypogonadism (amenorrhea), bone loss (osteoporosis), sick euthyroid, cortisol dysregulation
GI	Gastroparesis, constipation, pancreatitis, esophageal tears (Mallory‑Weiss), gastric rupture
Electrolyte	Hypokalemia, hyponatremia, hypophosphatemia (refeeding), metabolic alkalosis (vomiting)
Renal	Stones, renal failure (dehydration, laxative abuse)
Dental	Enamel erosion, caries, parotid enlargement (BN)
Neurologic	Brain volume loss, cognitive impairment, seizures (electrolytes)

Evidence‑Based Treatment

• AN: Family‑Based Treatment (FBT) for adolescents; CBT‑E, specialist supportive clinical management (SSCM), MANTRA for adults. Weight restoration is primary.
• BN: CBT‑E (first‑line); fluoxetine 60 mg adjunctive; interpersonal psychotherapy (IPT).
• Medical stabilization: Inpatient for severe malnutrition (BMI <15, HR <40, electrolytes, ECG abnormalities). Refeeding protocol with phosphate monitoring.
• Multidisciplinary team: Physician, dietitian, therapist, psychiatrist.

Early intervention improves prognosis. Full recovery is achievable with sustained, specialized care.