09: Eating Disorders

Question 1

List the various feeding & eating disorders and their core features.

Answer 1

1. Anorexia nervosa (AN): persistent caloric restriction –> low weight; fear of weight gain
2. Bulimia nervosa (BN): binge eating & purging
3. Binge eating disorder (BED): binge eating without purging
4. Avoidant/restrictive food intake disorder (ARFID): restrictive food intake, but not AN
5. Pica: ingestion of non-nutritive, non-food substances
6. Rumination disorder: regurgitation of ingested food

Question 2

What are the DSM-V criteria for anorexia nervosa?

Answer 2

1. Restriction of energy intake relative to requirements, leading to a weight that is less than minimally normal
2. Intense fear of gaining weight/persistent behavior to avoid weight gain
3. Disturbance in body image

Question 3

What are the associated behavioral features of anorexia nervosa?

Answer 3

1. Binge eating
2. Obsession with food
3. Laxative/diuretic abuse
4. Depression
5. Peculiar eating
6. Increased physical activity
7. Compulsive behavior
8. Social isolation

Mnemonic: BOLD PICS

NB: Increased physical activity is the only behavioral symptom unique to AN; all others are symptoms of starvation as well.

Question 4

What are the associated physiological features of anorexia nervosa?

Answer 4

• Hypothermia, bradycardia, hypotension
• Lanugo: downy growth of hair
• Edema
• Anemia, leukopenia
• Increased LFT’s
• Low estrogen, LH, FSH –> amenorrhea (absence of menstruation)
• Low-normal T4
• High cholesterol
• Decreased brain mass
• Osteoporosis

NB: All are also symptoms of starvation; non-specific.

Question 5

What are the long-term outcomes of anorexia nervosa?

Answer 5

• Full recovery: 1/3 - 1/2
• Death: 5% per decade of follow-up
• Alive but not well: the rest
• Obesity: rare

Question 6

What are the DSM-V criteria for bulimia nervosa?

Answer 6

1. Recurrent episodes of binge eating
2. Recurrent inappropriate compensatory behavior to prevent weight gain (e.g., vomiting)
3. Binge eating and inappropriate behavior both occur, on average, at least once a week for three months
4. Self-evaluation is unduly influenced by body shape and weight
5. Disturbance does not occur exclusively during episodes of anorexia nervosa

Question 7

What is DSM-V’s definition of a binge?

Answer 7

• Eating in a discrete period of time (e.g., 2 hours) an amount of food definitely larger than normal
• Sense of lack of control over eating during the episode

Question 8

What are the signs and symptoms of bulimia nervosa?

Answer 8

• Irregular menses
• Dental erosion
• Enlarged salivary glands
• Laxative dependence
• Ipecac toxicity
• Gastic rupture
• Calloused digits on dorsum

Question 9

What are the laboratory abnormalities characteristic of bulimia nervosa?

Answer 9

• Hypokalemia/chloremia/natremia
• Alkalosis in vomiters
• Acidosis in laxative abusers
• Hyperamylasemia (excess of pancreatic enzyme amylase in blood)

Question 10

What are the DSM-V criteria for binge eating disorder?

Answer 10

1. Recurrent episodes of binge eating
2. Episodes associated with at least three of the following:
   
   1. Eating much more rapidly than normal
   2. Eating until feeling uncomfortably full
   3. Eating large amounts when not physically hungry
   4. Eating alone because of embarrassment
   5. Feeling disgusted, depressed or guilty after overeating
3. Marked distress present
4. Occurs on average at least once a week for 3 months
5. Not associated with recurrent use of inappropriate compensatory behavior and does not exlcusively occur during course of bulimia nervosa or anorexia nervosa

Question 11

What are the associated features of binge eating disorder?

Answer 11

• Increased frequency of mood and anxiety disorders
• Increased risk of weight gain

Question 12

Describe the following typical clinical features for AN, BN and BED:

1. Body weight
2. Age at presentation
3. F:M ratio
4. Lifetime prevalence

Answer 12

Anorexia nervosa:

1. Low
2. Mid-adolescence
3. 9:1
4. 0.5-1% women

Bulimia nervosa:

1. Normal
2. Adolescence to young adulthood
3. 9:1
4. 1-2% women

Binge eating disorder:

1. High
2. Middle-age
3. 3:2
4. 2-4%

Question 13

What is the theory on the development of eating disorders?

Answer 13

• Predisposing factors
  
  • Female
  • Genes
  • Environment
  • Society
• Precipitating factors
  
  • Stresses of adolescence
• Perpetuating factors
  
  • Dieting –> binge eating –> dieting

Question 14

How is persistent behavior which is not innate learned?

Answer 14

• Action-outcome learning (operant conditioning): goal directed
• Stimulus-response learning: habit formation (via over-training)

NB: Eating disorders may persist because they have become well-entrenched habits

Question 15

Describe the treatments for AN, BN and BED:

1. Psychological
2. Pharmacological

Answer 15

Anorexia nervosa:

1. Behavioral intervention (to restore weight), family-based therapy (youth), supportive/CBT (adults)
2. None (perhaps olanzapine?)

Bulimia nervosa:

1. CBT
2. SSRIs

Binge eating disorder:

1. CBT, others
2. SSRIs, weight loss agents