Anorexia Nervosa – High-yield Notes

Anorexia Nervosa – High-yield Notes for USMLE, NCLEX, NEET PG Exams

Overview

• Definition: Anorexia nervosa is an eating disorder characterized by an intense fear of gaining weight, a distorted body image, and severe restriction of food intake, leading to significantly low body weight.
• Etiology: Multifactorial, involving genetic, psychological, and sociocultural factors.
• Epidemiology: More common in females, typically onset in adolescence.

Pathophysiology

• Psychological Factors: Perfectionism, obsessive-compulsive traits, and a strong desire for control.
• Biological Factors: Genetic predisposition, abnormalities in neurotransmitter systems (e.g., serotonin).
• Sociocultural Factors: Societal emphasis on thinness and body image.

Clinical Features

• Behavioral Symptoms:
  • Restrictive eating patterns
  • Excessive exercise
  • Preoccupation with food, dieting, and body image
• Physical Signs:
  • Significant weight loss (BMI < 18.5)
  • Amenorrhea (absence of menstruation)
  • Bradycardia (slow heart rate)
  • Hypotension (low blood pressure)
  • Hypothermia (low body temperature)
  • Lanugo (fine, downy hair on the body)
  • Dry skin and brittle hair
  • Peripheral edema
  • Osteoporosis

Subtypes

• Restricting Type: Weight loss is achieved through dieting, fasting, and/or excessive exercise.
• Binge-Eating/Purging Type: Recurrent episodes of binge eating or purging behavior (e.g., self-induced vomiting, misuse of laxatives, diuretics).

Risk Factors

• Genetic predisposition
• Family history of eating disorders
• Psychiatric comorbidities: Depression, anxiety disorders, obsessive-compulsive disorder (OCD)
• Sociocultural factors: Pressure to conform to societal ideals of beauty and thinness

Diagnosis

• DSM-5 Criteria:
  • Restriction of energy intake relative to requirements, leading to significantly low body weight.
  • Intense fear of gaining weight or becoming fat, even though underweight.
  • Disturbance in the way one’s body weight or shape is experienced, undue influence of body weight or shape on self-evaluation, or persistent lack of recognition of the seriousness of the current low body weight.
• Laboratory Tests:
  • Electrolyte panel: Hypokalemia, hyponatremia
  • CBC: Anemia, leukopenia
  • Thyroid function tests: Low T3 and T4
  • Bone density scan: Osteopenia or osteoporosis
• Psychological Assessment: Evaluate for comorbid psychiatric conditions.

Treatment

• Nutritional Rehabilitation:
  • Gradual weight restoration through a structured meal plan.
  • Monitoring for refeeding syndrome (electrolyte imbalance and fluid shifts).
• Psychotherapy:
  • Cognitive-behavioral therapy (CBT): First-line treatment; focuses on altering dysfunctional thoughts and behaviors related to eating and body image.
  • Family-based therapy (FBT): Particularly effective for adolescents.
• Pharmacotherapy:
  • Limited role; SSRIs (e.g., fluoxetine) may be used for comorbid depression or anxiety.
• Medical Monitoring:
  • Regular monitoring of weight, vital signs, and electrolytes.
  • Hospitalization in severe cases (e.g., BMI < 15, hemodynamic instability, severe electrolyte imbalance).

Complications

• Cardiovascular:
  • Arrhythmias
  • Heart failure
  • Mitral valve prolapse
• Endocrine:
  • Amenorrhea
  • Osteoporosis
  • Hypoglycemia
• Gastrointestinal:
  • Gastroparesis
  • Constipation
• Renal:
  • Renal failure
• Psychiatric:
  • Depression
  • Anxiety
  • Suicide

Prognosis

• Outcome: Variable; early intervention improves prognosis.
• Factors Affecting Prognosis: Severity of illness, duration of untreated illness, presence of comorbid conditions, family support.

Prevention

• Education and Awareness: Promoting healthy body image and eating habits.
• Early Detection: Screening for eating disorders in at-risk populations.

Mnemonics

• ANOREXIA for features of Anorexia Nervosa:
  • Amenorrhea
  • Nutritional deficiency
  • Obsessive behavior
  • Restricted diet
  • Emaciation
  • Xtreme weight loss
  • Image distortion
  • Anxiety about weight gain

Chart: Diagnostic Approach to Anorexia Nervosa

Step	Diagnostic Tool	Purpose
1	Clinical Examination	Identify physical signs and symptoms
2	DSM-5 Criteria	Confirm diagnosis
3	Laboratory Tests	Detect electrolyte imbalances, organ damage
4	Psychological Assessment	Evaluate comorbid psychiatric conditions
5	Bone Density Scan	Assess for osteopenia or osteoporosis

Table: Treatment Modalities for Anorexia Nervosa

Treatment Modality	Example(s)	Remarks
Nutritional Rehabilitation	Structured meal plan	Prevents refeeding syndrome
Psychotherapy	Cognitive-Behavioral Therapy (CBT), Family-Based Therapy (FBT)	First-line treatment
Pharmacotherapy	Fluoxetine (SSRI)	Limited role; for comorbid conditions
Medical Monitoring	Regular weight and electrolyte checks	Monitor for complications

Key Points

• Early intervention with nutritional rehabilitation and psychotherapy is crucial.
• CBT and FBT are the most effective psychotherapeutic approaches.
• Monitoring for refeeding syndrome is essential during nutritional rehabilitation.
• Electrolyte imbalances and cardiovascular complications are common and require careful monitoring.

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