Physiological Aspects of Bulimia Nervosa

Bulimia nervosa is characterized by continual binge/purge episodes in attempts to control weight. The American Psychiatric Association outlines the diagnostic criteria for bulimia nervosa as follows: binge eating with inappropriate compensatory behaviors (vomiting, laxative abuse, overexercise, fasting, with holding of insulin, etc.) occurring at least twice a month for three months. The person must be overconcerned with body weight and shape and have a body mass index (BMI) above 17.5.

While a binge is extremely hard to define and may come in the objective (most would agree that the current episode qualified as a binge) or subjective (the person could have eaten a few bites of something, possibly a forbidden food, feels out of control, considers the current eating occurrence a binge and compensates by engaging in purging behaviors), the diagnostic criteria for bulimia nervosa specifies eating at one sitting what most would consider much larger than average in that period of time. The person must also experience a loss of control accompanying this episode.

Persons with purging type anorexia nervosa may also engage in some of the aforementioned purging episodes. Physiological consequences are likely to be seen systemwide. Initial signs of bulimia nervosa may include erosion of tooth enamel or enlargement of salivary glands. Gastrointestinal changes including esophageal narrowing or erosion, stomach or esophagus ulcers or tears, and gastric reflux may occur. In the colon nerve, damage and dependency on laxative may be long-term problems. Slowed gastric emptying, cholecystokinin, ghrelin, and peptide yy release in response to food may encourage overeating. Electrolyte imbalances, which can result from purging along with fluid shifts, carry severe consequences which could include heart attack and death.

Bulimia nervosa has been a growing problem since the mid-1900s. Estimates of the prevalence of bulimia nervosa are 1 to 3 percent of the female population, but higher in the female college population. A small amount of males suffer from bulimia nervosa comprising 5 to 10 percent of the total population with this disorder. Bulimia nervosa is costly to treat and can have long-term devastating physiological consequences.

Despite often being normal weight, people with bulimia nervosa still suffer devastating physiological complications and death. Tooth decay and loss of tooth enamel are some of the early complications of bulimia nervosa and may actually alert health professions to what is occurring with the individual. The acidic content of the vomit is able to wear away the enamel on teeth, especially the back of the teeth. The continual exposure to this stomach acid causes long-term tooth damage and dental staining. Gingivitis and cavities may also result from bulimic episodes. Cuts in the mouth may result from purging episodes. Damage to oral mucosa can also occur from purging, dry mouth following purging episodes, and from poor dental hygiene often seen in persons with bulimia nervosa.

Along with tooth damage and decay, persons with bulimia nervosa often suffer from swollen glands (especially the parotid or salivary glands) and puffy cheeks. Parotid hypertrophy may result due to the increased demands for saliva production following purging episodes. Additionally, high amounts of amalyase enzyme are present in persons with bulimia nervosa. Furthermore, increased production of amalyase does not come from pancreatic secretion. Therefore, it is possible that increased need for amalyase to digest the large amounts of food being consumed is met by the parotid gland. This increased strain would help contribute to the hypertrophy noted in the parotid glands. Stones may form in the salivary ducts as a result of constant purging. In addition, over time, the [Page 609]salivary glands may tire and begin to produce less saliva, resulting in dry mouth. In most cases, the parotid glands return to normal size when the bingeing and purging episodes have ceased.

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