Anorexia Nervosa vs Bulimia Nervosa
Anorexia nervosa and Bulimia nervosa are psychiatric disorders characterized by severe disturbances in eating behaviors. Both occur primarily in previously healthy young women who become overly concerned with their body weight and shape. Many patients with Bulimia nervosa have past histories of anorexic behavior. On the other hand, many patients with Anorexia nervosa have histories of binge eating and purging behavior. Both of them are more prevalent in cultures where food is plentiful and in which being thin is associated with attractiveness.
In spite of having so many similarities there are certain differences in between the two which make them separate entities. Some of the major differences are:
|Improve this chart||Anorexia Nervosa||Bulimia Nervosa|
|Prevalence in women:||0.5%||1-3%|
|Weight:||Markedly reduced||usually normal|
|Binge eating:||25-50%||required for diagnosis|
|Mortality:||~5% per decade||low - often sudden due to arrythmias induced by electrolyte abnormalities|
|Cardiovascular:||low BP, decreased heart rate||dehydration, imbalanced electrolytes (esp. potassium), low BP, orthostatic hypotension, arrythmias d/t electrolyte imbalance|
|Skin / extremities:||dry skin, lanugo hair||dry skin, hair loss, brittle nails|
|Glucose levels:||Hypoglycemia||usually normal|
|Sex hormones level:||Low estrogen or testosterone||usually normal|
|LH and FSH level:||low||usually normal|
|Thyroxine levels:||low normal||usually normal|
|Cortisol levels:||increased||usually normal|
|Onset:||mid adolescence||late adolescence|
edit Diagnostic criteria
In anorexia nervosa, there is refusal by the patient to maintain body weight at or above a minimally normal weight for age and height. There is intense fear of gaining weight or becoming fat even though they are underweight. In post-menarchal females, amenorrhea, i.e., the absence of at least three consecutive menstrual cycles.
In Bulimia nervosa, there are recurrent episodes of binge eating. An episode of binge eating is characterized by both of the following:
- Eating, in a discrete period of time an amount of food that is definitely larger than most people would eat during a similar period of time and under similar circumstances.
- Sense of lack of control over eating during the episode. Recurrent inappropriate compensatory behavior in order to prevent weight gain, such as self induced vomiting, misuse of laxatives or diuretics, enemas, or other medications; fasting; or excessive exercise.
edit Clinical characteristics
- Anorexia nervosa has onset in mid adolescence whereas Bulimia usually starts in late adolescence or adulthood.
- Weight at diagnosis is markedly decreased in Anorexia Nervosa while it is usually normal in Bulimia.
- Amenorrhea (absence of menstrual period) is usually present in patients with Anorexia Nervosa while it is usually normal in the other group of patients.
- Binge eating is present in 25-50 % of patients with anorexia nervosa while it is present in 100 % of patients with Bulimia nervosa.
- Mortality is around 5% in 10 years for Anorexia nervosa while it is very low in Bulimia nervosa.
- Antisocial behavior can be found in patients with Bulimia Nervosa while it is rare in patients with Anorexia nervosa.
edit Physical and laboratory findings
Cardiovascular changes are more common in patients with Anorexia nervosa like decreased heart rate and decreased blood pressure while these changes are rare with Bulimia Nervosa. Skin changes like lanugo hair, dryness etc. are common associates of patients with Anorexia Nervosa while they are rare in patients with Bulimia Nervosa. Hormonal imbalances like low estrogen or testosterone, low LH and FSH, low normal thyroxine etc. are common in patients with Anorexia Nervosa while they are rare in patients with Bulimia nervosa.
For Anorexia Nervosa the most effective form of psychotherapy is family therapy in which the family members of the patients are also consulted by the psychiatrist along with the patient. For Bulimia Nervosa the most effective form of treatment is cognitive and behavioral therapy along with antidepressants.
edit See Also
- Harrison's principles of internal medicine volume 1
- Current medical diagnosis and treatment