Bulimia nervosa

Bulimia nervosa

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Bulimia nervosa

Bulimia nervosa is an eating disorder characterized by recurrent binge eating, followed by compensatory behaviors, referred to as "purging".^[1] The most common form?practiced more than 75% of people with bulimia nervosa?is self-induced vomiting; fasting, the use of laxatives, enemas, diuretics, and over exercising are also common.^[2]

The word bulimia derives from the Latin (b?l?mia) from the Greek ???????? (boul?mia; ravenous hunger), a compound of ???? (bous), ox + ????? (l?mos), hunger.^[3]

Diagnosis
Prevalence
Effects
Causes
Related disorders
Treatment
See also
Informational links
References

Diagnosis

According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV TR) published by the American Psychological Association, the criteria for diagnosing a patient with bulimia are:

Recurrent episodes of binge eating. An episode of binge eating is characterized by both of the following:
- Eating, in a fixed period of time, an amount of food that is definitely larger than most people would eat under similar circumstances.
- A lack of control over eating during the episode: a feeling that one cannot stop eating or control what or how much one is eating.
Recurrent inappropriate compensatory behavior to prevent weight gain, such as: self-induced vomiting; misuse of laxatives, diuretics, or other medications; fasting; excessive exercise.
Self-evaluation is unduly influenced by body shape and weight.
These symptoms occur at least twice a week on average and persist for at least 3 months.
The disturbance does not occur exclusively during episodes of Anorexia Nervosa.^[4]

There are two sub-types of Bulimia Nervosa: purging and non-purging.

Purging Type: the patient uses self-induced vomiting (which may include use of emetics such as syrup of ipecac) and other ways to rapidly remove food from the body before it can be digested, such as laxatives, diuretics, and enemas.
Non-purging Type: occurring in approximately 6%-8% of cases, in which the patient uses excessive exercise or fasting after a binge to offset the caloric intake after eating. Purging-type bulimics may also exercise or fast, but as a secondary form of weight control.^[4]

The onset of Bulimia Nervosa is often during adolescence (between 13 and 20 years of age), with many sufferers relapsing in adulthood into episodic binging and purging even after initially successful treatment and remission.^[5]

Bulimia Nervosa can be difficult to detect, compared to Anorexia Nervosa , because bulimics tend to be of average or slightly above or below average weight. Many bulimics may also engage in significantly disordered eating and exercising patterns without meeting the full diagnostic criteria for Bulimia Nervosa.^[6]

Prevalence

The collection of data on the incidence of bulimia nervosa in the general population is limited. Most studies conducted thus far have been on convenience samples from hospital patients, high school or university students. These have yielded a wide range of results: between 0% and 2.1% of males, and between 0.3% and 7.3% of females.^[7] A more recent study indicates that 10% of adolescent girls and 3% of adolescent boys binge eat and purge at least once weekly. ^[8]

Country	Year	Sample size and type	Incidence
USA	1996	1152 college students	0.2% male	1.3% female^[9]
USA	1992	799 college students	0.4% male	5.1% female^[10]
Norway	1995	19067 psychiatric patients	0.7% male	7.3% female^[11]
Australia	1998	4200 high school students	0.3% combined^[12]
Canada	1995	8116 (random sample)	0.1% male	1.1% female^[13]
Japan	1995	2597 high school students	0.7% male	1.9% female^[14]

Although bulimia is overwhelmingly a disease of young women, it can affect others. Former British Deputy Prime Minister John Prescott says he developed bulimia in his 60s ^[15].

Effects

These cycles often involve rapid and out-of-control eating, which may stop when the bulimic is interrupted by another person or the stomach hurts from overextension, followed by self-induced vomiting or other forms of purging. This cycle may be repeated several times a week or, in more serious cases, several times a day^[16], and may directly cause:

Chronic gastric reflux after eating.
Dehydration and hypokalemia caused by frequent vomiting.
Electrolyte imbalance, which can lead to cardiac arrhythmia, cardiac arrest, and even death
Esophagitis
Oral trauma, in which repetitive insertion of fingers or other objects causes lacerations to the lining of the mouth or throat.
Pancreatitis^[17]
Peptic ulcers
Perimolysis, or the erosion of tooth enamel by gastric acids.
Swollen salivary glands.^[18]
Tearing or rupture of the esophagus caused by repeated forced vomiting.
Severe caries ('cavities') as the stomach acid lowers the pH of the oral environment making the teeth far more susceptible to demineralization.

Causes

Bulimia is related to deep psychological issues and feelings of lack of control. Sufferers often use the destructive eating pattern to feel in control over their lives.^[19] They may hide or hoard food and overeat when stressed or upset. They may feel a loss of control during a binge, and consume great quantities of food (sometimes over 20,000 calories).^[20] After a length of time, the sufferer of bulimia will find that they no longer have control over their binging and purging. The binging becomes an addiction that seems impossible to break. Recovery is very hard, and often, in the early stages of recovery, the patient will gain weight as they rehydrate and obtain electrolytes that they have lost during the purging process. There are higher rates of eating disorders in groups involved in activities that emphasize thinness and body type, such as gymnastics, modeling, dance, cheerleading, running, acting, rowing(lightweights/coxwains) and figure skating.^[21] Bulimia is more prevalent among Caucasians. In one study, diagnosis of bulimia was correlated with high testosterone and low estrogen levels, and normalizing these levels with combined oral contraceptive pills reduced cravings for fat and sugar.^[22]

Related disorders

Bulimics are much more likely than non-bulimics to have an affective disorder, such as depression or general anxiety disorder: A 1985 Columbia University study on female bulimics at New York State Psychiatric Institute found 70% had suffered depression some time in their lives (as opposed to 25.8% for adult females in a control sample from the general population), rising to 88% for all affective disorders combined.^[23] Another study by the Royal Children's Hospital in Melbourne on a cohort of 2000 adolescents similarly found that those meeting at least two of the DSM-IV criteria for bulimia nervosa or anorexia nervosa had a sixfold increase in risk of anxiety and a doubling of risk for substance dependency.^[24]

Treatment

There is no approved or generally accepted treatment for bulimia. Generally treatment is predicated on a real or hypothetical relationship to other disorders, Some researchers have hypothesized a relationship to mood disorders. In consequence, clinical trials have been conducted with tricyclic antidepressants, MAO inhibitors, mianserin, fluoxetine, lithium carbonate, nomifensine, trazodone and bupropion. ^[25] Research groups who have seen a relationship to seizure disorders have attempted treatment with, phenytoin,carbamazepine and valproic acid. A third group has viewed bulimia as an addiction disorder, The opiate antagonist naloxone and naltrexone which also block cravings for gambling have been used.^[26] There has also been limited use of Topamax which blocks cravings for opiates, cocaine, alcohol and food.,^[27] Some researchers also report positive outcomes when bulimics are treated in an addiction-disorders inpatient unit. ^[28]. None of these approaches have been consistently effective.