Anorexia nervosa vs Bulimia nervosa and binge-eating disorder
How to tell Anorexia nervosa and Bulimia nervosa and binge-eating disorder apart when a board question makes them look alike.
Low body weight points to anorexia; binge plus compensation points to bulimia; binge without compensation points to binge-eating disorder.
Side by side
Anorexia nervosa has restriction of energy intake with significantly low body weight, intense fear of weight gain, and disturbed body image.
Bulimia nervosa has binge eating with compensatory behaviors and usually normal weight; binge-eating disorder has binge eating without compensatory behaviors.
Anorexia is driven by restriction and weight/shape disturbance severe enough to produce low body weight, with restricting or binge-purge subtype possible.
Bulimia and binge-eating disorder share loss-of-control binges; purging, laxatives, fasting, or excessive exercise separates bulimia from binge-eating disorder.
Low BMI, amenorrhea, bradycardia, lanugo, osteoporosis, hypothermia, and electrolyte abnormalities from purging support anorexia nervosa.
Parotid enlargement, dental enamel erosion, metabolic alkalosis, hypokalemia, and normal weight support bulimia; obesity or metabolic syndrome may accompany binge-eating disorder.
The trap
Purging can occur in anorexia binge-purge subtype, so low body weight versus normal/high weight is a key separator.
The repair move
For eating disorders, check weight status first, then ask whether binges and compensatory behaviors are present.
Try a free question
CoreA patient has BMI 16, intense fear of gaining weight, distorted body image, amenorrhea, bradycardia, and restrictive eating. Which diagnosis is most likely?
Show answer and explanation
Answer: A. Anorexia nervosa. Significantly low body weight plus fear of weight gain and disturbed body image supports anorexia nervosa.
Why the other choices are tempting
- B. Bulimia nervosa usually has normal weight and compensatory behaviors after binges.
- C. Binge-eating disorder has binges without compensatory behavior and without the low-weight criterion.
- D. Body dysmorphic disorder centers on perceived appearance defects outside the eating-disorder weight/shape syndrome.
- E. Illness anxiety disorder centers on fear of having illness.
Flashcards
Tap a card to flip it.
What weight finding supports anorexia nervosa?
Significantly low body weight supports anorexia nervosa.
What behavior separates bulimia from binge-eating disorder?
Compensatory behavior such as vomiting, laxatives, fasting, or excessive exercise separates bulimia from binge-eating disorder.
Quick answers
What is the fastest way to tell Anorexia nervosa from Bulimia nervosa and binge-eating disorder?
Low body weight points to anorexia; binge plus compensation points to bulimia; binge without compensation points to binge-eating disorder.
What is the key clue for Anorexia nervosa?
Anorexia nervosa has restriction of energy intake with significantly low body weight, intense fear of weight gain, and disturbed body image.
What is the key clue for Bulimia nervosa and binge-eating disorder?
Bulimia nervosa has binge eating with compensatory behaviors and usually normal weight; binge-eating disorder has binge eating without compensatory behaviors.
What is the common trap with Anorexia nervosa vs Bulimia nervosa and binge-eating disorder?
Purging can occur in anorexia binge-purge subtype, so low body weight versus normal/high weight is a key separator.