Chapter 8 Bulimia Nervosa
PATHOPHYSIOLOGY
Bulimia nervosa is a nutritional and psychologic disorder characterized by rapid consumption of large quantities of food (bingeing), followed by any of a number of behaviors used to prevent weight gain. Eating occurs during discrete periods of time. Self-induced vomiting is the most commonly used method to avoid weight gain. Other purging methods include use of laxatives, enemas, and diuretics, as well as of cathartics, thyroid medications, diet pills and appetite suppressants, stimulants, and nutritional supplements; diabetics may neglect to take their insulin.
Complications are related to the method of purging. Purging is ineffective when large quantities are consumed, because digestion begins rapidly and much of the food is digested and absorbed. Fluids and electrolytes are lost in the large intestine with laxative use, but digestion takes place in the small intestine. Fasting and excessive exercise may also be used as an attempt to compensate for intake and prevent weight gain. Most individuals develop a chronic pattern of binge/purge behavior. Bingeing may be triggered by dysphoria, stress, or negative feelings related to body image. Because of associated feelings of shame, bingeing is often done in secrecy. Individuals typically feel out of control during bingeing episodes. For some, vomiting becomes the goal in and of itself.
Impulse control problems such as alcohol abuse and shoplifting often coexist with bulimia. As in individuals with anorexia nervosa, there is an excessive focus on one’s body. Self-worth is connected to physical appearance. Unlike the individual with anorexia, the bulimic individual is likely to be within the normal weight range for age and height, but weight may also vary by 10 pounds or more. The diagnostic criteria of the Diagnostic and Statistical Manual of Mental Disorders, fourth edition, text revision (DSM-IV-TR), are presented in Box 8-1.
Box 8-1 Diagnostic Criteria for Bulimia Nervosa
1. Recurrent episodes of binge eating occur. An episode of binge eating is characterized by both of the following:
2. Recurrent inappropriate compensatory behavior occurs to prevent weight gain, such as self-induced vomiting; misuse of laxatives, diuretics, enemas, or other medications; fasting; or excessive exercise.
3. The binge eating and inappropriate compensatory behaviors both occur, on average, at least twice a week for 3 months.
4. Self-evaluation is unduly influenced by body shape and weight.
5. The disturbance does not occur exclusively during episodes of anorexia nervosa.
Purging Type
During the current episode of bulimia nervosa, the person has regularly engaged in self-induced vomiting or the misuse of laxatives, diuretics, or enemas.
Nonpurging Type
During the current episode of bulimia nervosa, the person has used other inappropriate compensatory behaviors, such as fasting or excessive exercise, but has not regularly engaged in self-induced vomiting or the misuse of laxatives, diuretics, or enemas.
From American Psychiatric Association: Diagnostic and statistical manual of mental disorders, ed 4, text revision (DSM-IV-TR), Washington, DC, 2000, The Association.
Bulimia nervosa is difficult to diagnose because bulimics are normal or above average in weight, may not show any physical signs, and are not forthcoming about their condition; symptoms are typically concealed, and the family may be in denial. Minorities and men are largely overlooked, because clinicians see eating disorders as upper socioeconomic female disorders. Males are even more reluctant to disclose eating disorders behavior because of guilt and shame; the course is the same as for females in terms of secrecy and physical health problems.
The risk factors for men include athletic sports that require low body fat or are weight sensitive (swimming, gymnastics, and wrestling), negative life experiences, teasing, physical abuse, homosexuality, and the presence of a comorbid psychiatric condition. During the wrestling season, 17% of high school wrestlers meet short-term criteria for an eating disorder; a small minority do not recover after the season. Males generally use excessive exercise after bingeing rather than purging. In female clients, distorted body image leads to an overestimation of weight. Being a gay male is a documented risk, not because of sexual orientation but because of the value placed on lean muscularity. Because the ideal male form is lean and muscular, males are more likely to underestimate their weight. The reverse of anorexia, with body dismorphia at its core, is bigarexia. Often steroids are abused in an attempt to gain defined muscle mass and impossibly low body fat.
INCIDENCE
1. Bulimia nervosa affects about 2% to 4% of adolescent girls and fewer than 1% to 5% of adolescent boys.
2. Most individuals with bulimia manifest symptoms in the latter half of adolescence.
3. Female/male ratio is 10:1; there are community-based epidemiologic studies citing a 3:1 ratio.
4. Bulimia is independent of social class, unlike anorexia, which occurs predominantly in higher socioeconomic classes.
5. There is high comorbidity with anxiety and affective disorders and obsessive-compulsive disorder.
6. Fifty percent of bulimic individuals have an alcoholic relative and relatives with a high incidence of eating disorders, obesity, and affective disorders.
7. Large numbers of adolescents do not meet full DSM-IV-TR criteria for bulimia or anorexia but experience psychologic and physiologic consequences of eating disorders.
CLINICAL MANIFESTATIONS
1. Some bulimic individuals are in the normal range for their height and weight, some a few pounds overweight, and some a few pounds underweight
2. Secret and solitary binge eating as means of dealing with anxiety and stress
3. In one episode, an individual may consume thousands of calories
