Anorexia nervosa is an eating disorder characterized by refusal to maintain a minimally accepted body weight, intense fear of weight gain, and distorted body image. Inadequate calorie intake or excessive energy expenditure results in severe weight loss (see also bulimia and intentional weight loss).

The exact cause of anorexia nervosa is not known, but social attitudes towards body appearance and family factors are believed to play a role in its development. The condition usually occurs in adolescence or young adulthood. It is more common in women, affecting 1-2% of the female population and only 0.1-0.2% of males.

Anorexia nervosa is seen mainly in Caucasian women who are high academic achievers and have a goal-oriented family or personality. Some experts have suggested that conflicts within a family may contribute to this eating disorder. It is thought that anorexia is a way for a child to draw attention away from marital problems, for example, and bring the family back together.

Other psychologists have suggested that anorexia may be an attempt by young women to gain control and separate from their mothers. The causes, however, are still not well understood.

• weight loss of 15% or greater below the expected weight
• inappropriate use of laxatives, enemas, or diuretics (water pills) in an effort to lose weight
• self-imposed food intake restrictions, often hidden
• absence of menstruation
• skeletal muscle atrophy
• loss of fatty tissue
• low blood pressure
• dental cavities may be present with self-induced vomiting
• blotchy or yellow skin
• depression may be present in addition to the eating disorder
• most individuals with anorexia nervosa refuse to recognize that they have an eating disorder (denial)

Diagnosis is based upon ruling out other causes of endocrine, metabolic, digestive, and central nervous system abnormalities to explain the weight loss. This could include celiac disease, inflammatory bowel disease, Addison's disease, and many other possible conditions.

Tests that may be used to assess cause of or damage from weight loss include:

• chem-20
• urinalysis
• thyroid function tests
• other blood and urine tests
• ECG

The biggest challenge in treating anorexia nervosa is having the person recognize that their eating behavior is itself a problem, not a solution to other problems. However, most people who suffer from anorexia nervosa deny that they have an eating disorder. Therefore, most individuals enter treatment when their condition is fairly advanced.

The purpose of treatment is first to restore normal body weight and eating habits, and then attempt to resolve psychological issues. Hospitalization may be indicated in some cases (usually when body weight falls below 30% of expected weight).

Supportive care by health care providers, structured behavioral therapy, psychotherapy, and anti-depressant drug therapy are some of the methods that are used for treatment. Severe and life-threatening malnutrition may require intravenous feeding.

A support group where members share common experiences and problems may be able to help. See eating disorders - support group.

Anorexia nervosa is a serious and potentially deadly medical condition. By some estimates, it leads to death in 10% of cases. Experienced treatment programs have a two-thirds success rate in restoring normal weight, but relapse is common.

Women who develop this eating disorder at an early age have a better chance of complete recovery. Most people with anorexia will continue to prefer a lower body weight and be preoccupied with food and calories to some extent, however. Weight management may be difficult, and long-term treatment may be necessary to help maintain a healthy body weight.

The presence of any of these suggests a severe disease, and hospitalization may be required:

• severe dehydration, possibly leading to cardiovascular shock
• electrolyte imbalance (such as potassium insufficiency)
• cardiac arrhythmias related to the loss of cardiac muscle and electrolyte imbalance
• severe malnutrition
• thyroid gland deficiencies which can lead to cold intolerance and constipation
• appearance of fine baby-like body hair (lanugo)
• bloating or edema
• decrease in white blood cells which leads to increased susceptibility to infection
• osteoporosis
• tooth erosion and decay with self-induced vomiting
• seizures related to fluid shifts due to excessive diarrhea or vomiting

Call your health care provider if symptoms suggestive of anorexia nervosa are present.

Go to the emergency room or call the local emergency number (such as 911) if fainting, irregular pulse, seizures, or other severe symptoms develop in a person with anorexia nervosa.

In some cases, prevention may not be possible. Encouraging healthy, realistic attitudes toward weight and diet may be helpful. Sometimes, counseling can help.