Weight Loss Eating Disorders: Anorexia Nervosa

Introduction

Anorexia nervosa is a serious eating disorder that significantly impacts physical and mental health. This comprehensive guide, tailored for MCCQE1 preparation, focuses on the Canadian perspective of anorexia nervosa, its diagnosis, and management.

Epidemiology in Canada

Understanding the prevalence and distribution of anorexia nervosa in Canada is crucial for MCCQE1 preparation:

• Prevalence: Approximately 0.3-0.4% of young Canadian women
• Age of onset: Typically between 14-18 years old
• Gender distribution: More common in females, but increasing recognition in males
• At-risk populations: Athletes, dancers, models, and individuals with a family history of eating disorders

Diagnostic Criteria

For MCCQE1 preparation, it's essential to understand the diagnostic criteria for anorexia nervosa according to the DSM-5:

1. Restriction of energy intake leading to 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

Clinical Presentation

Recognizing the signs and symptoms of anorexia nervosa is crucial for MCCQE1 success:

Medical Complications

Understanding the multi-system effects of anorexia nervosa is vital for MCCQE1 preparation:

Canadian Guidelines for Management

The following guidelines are specific to Canadian healthcare practices and are important for MCCQE1 preparation:

1. Multidisciplinary approach: Involve a team including a physician, psychiatrist, psychologist, and dietitian.
2. Medical stabilization: Address any life-threatening complications first.
3. Nutritional rehabilitation: Gradual refeeding to avoid refeeding syndrome.
4. Psychotherapy: Cognitive Behavioral Therapy (CBT) or Family-Based Treatment (FBT) for adolescents.
5. Pharmacotherapy: Limited role, mainly for comorbid conditions like depression or anxiety.
6. Monitoring: Regular follow-ups to track weight gain and address any medical complications.

Refeeding Syndrome

Understanding refeeding syndrome is crucial for safe management of anorexia nervosa:

Refeeding Syndrome = Rapid ↑ in insulin → ↓ phosphate, magnesium, potassium

Prevention:

• Start at 20-25 kcal/kg/day
• Increase by 200-300 kcal every 2-3 days
• Monitor electrolytes closely
• Supplement phosphate, thiamine, and multivitamins

CanMEDS Framework Application

For MCCQE1 success, understand how the CanMEDS roles apply to anorexia nervosa management:

1. Medical Expert: Diagnose and manage anorexia nervosa and its complications
2. Communicator: Discuss sensitive topics with patients and families
3. Collaborator: Work effectively in a multidisciplinary team
4. Leader: Coordinate care across different healthcare settings
5. Health Advocate: Promote awareness and early intervention for eating disorders
6. Scholar: Stay updated on latest research and guidelines
7. Professional: Maintain patient confidentiality and provide ethical care

Key Points to Remember for MCCQE1

• Anorexia nervosa has the highest mortality rate among psychiatric disorders
• Early intervention is crucial for better outcomes
• Refeeding syndrome is a potentially fatal complication of treatment
• Family-Based Treatment (FBT) is the first-line treatment for adolescents in Canada
• Regular monitoring of physical and mental health is essential throughout treatment
• Consider cultural factors in body image and eating behaviors in Canada's diverse population

Sample Question

A 16-year-old female presents to her family physician with concerns about weight loss. She reports losing 10 kg over the past 3 months and has not had a menstrual period for 4 months. Her BMI is 17 kg/m². She admits to restricting her caloric intake and exercising for 2 hours daily. Which one of the following is the most appropriate next step in management?

• A. Prescribe an SSRI for possible depression
• B. Refer to an endocrinologist for amenorrhea workup
• C. Recommend a high-calorie diet to regain weight
• D. Refer for Family-Based Treatment (FBT)
• E. Admit to hospital for medical stabilization

Explanation

The correct answer is:

• D. Refer for Family-Based Treatment (FBT)

This patient presents with symptoms consistent with anorexia nervosa, including significant weight loss, amenorrhea, food restriction, and excessive exercise. Given her age and presentation, Family-Based Treatment (FBT) is the most appropriate next step according to Canadian guidelines.

FBT is considered the first-line treatment for adolescents with anorexia nervosa in Canada. It involves the family in the treatment process, which has shown better outcomes for this age group. While medical stabilization may be necessary in severe cases, this patient's presentation doesn't suggest immediate medical danger requiring hospitalization.

Prescribing an SSRI (A) is not appropriate as the primary intervention for anorexia nervosa. Endocrine referral (B) is not the priority, as amenorrhea is likely secondary to weight loss. Recommending a high-calorie diet (C) without proper support and monitoring could be dangerous. Hospital admission (E) may be necessary if outpatient treatment fails or if medical complications arise, but it's not the first-line approach in this case.

References

1. American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.).
2. Galmiche, M., Déchelotte, P., Lambert, G., & Tavolacci, M. P. (2019). Prevalence of eating disorders over the 2000–2018 period: a systematic literature review. The American Journal of Clinical Nutrition, 109(5), 1402-1413.
3. Golden, N. H., Katzman, D. K., Sawyer, S. M., & Ornstein, R. M. (2015). Position Paper of the Society for Adolescent Health and Medicine: medical management of restrictive eating disorders in adolescents and young adults. Journal of Adolescent Health, 56(1), 121-125.
4. Lock, J., & Le Grange, D. (2015). Treatment manual for anorexia nervosa: A family-based approach. Guilford Publications.
5. Findlay, S., Pinzon, J., Taddeo, D., & Katzman, D. K. (2010). Family-based treatment of children and adolescents with anorexia nervosa: Guidelines for the community physician. Paediatrics & Child Health, 15(1), 31-35.