Anorexia nervosa is an eating disorder that involves limiting the amount of food a person eats. It results in starvation and an inability to stay at the minimum body weight considered healthy for the person's age and height.

Persons with this disorder may have an intense fear of weight gain, even when they are underweight. Not eating enough food or exercising too much results in severe weight loss.

See also:

• Bulimia
• Intentional weight loss

Eating disorder - anorexia

The exact causes of anorexia nervosa are unknown. Many factors probably are involved. Genetics and social attitudes toward body appearance may play a role. Some experts have suggested that conflicts within a family may contribute to this eating disorder.

Anorexia is more common in people who have relatives with the disorder.

Risk factors include:

• Accepting society's attitudes about thinness
• Being a perfectionist
• Being female
• Experiencing childhood anxiety
• Feeling increased concern or attention to weight and shape
• Having eating and gastrointestinal problems during early childhood
• Having a family history of addictions or eating disorders
• Having parents who are concerned about weight and weight loss
• Having a negative self-image

Anorexia nervosa usually occurs in adolescence or young adulthood. It is more common in females. The eating disorder is seen mainly in Caucasian women who are high academic achievers and who have a goal-oriented family or personality.

People with anorexia may severely limit the amount of food they eat, or eat and then make themselves throw up. They may also use water pills (diuretics) and laxatives to lose weight.

Most individuals with anorexia nervosa do not recognize that they have an eating disorder.

Behaviors that may be noticed in a person with anorexia include:

• Cutting food into small pieces
• Exercising compulsively
• Going to the bathroom right after meals
• Quickly eating large amounts of food
• Restricting the amount of food eaten
• Using laxatives, enemas, or diuretics inappropriately in an effort to lose weight

Symptoms may include:

• Blotchy or yellow skin
• Confused or slow thinking
• Dental cavities due to self-induced vomiting
• Depression
• Dry mouth
• Extreme sensitivity to cold (wearing several layers of clothing to stay warm)
• Fine hair
• Low blood pressure
• No menstruation
• Poor memory or poor judgement
• Significant weight loss (15% or greater below normal weight)
• Wasting away of muscle and loss of body fat

A diagnosis of anorexia nervosa is not made until other causes of weight loss are ruled out. For example, extreme weight loss could be due to:

• Addison's disease
• Celiac disease
• Inflammatory bowel disease
• Other metabolic, endocrine, digestive, or nervous system disorders

Tests will be done to help determine the cause of weight loss, or what damage the weight loss has caused. These tests may include:

• CHEM-20
• ECG
• LH response to GnRH
• Thyroid function tests
• Urinalysis

The biggest challenge in treating anorexia nervosa is having the person recognize that the eating behavior is itself a problem, not a solution to other problems. However, most persons with anorexia nervosa deny that they have an eating disorder. Individuals often enter treatment when their condition is fairly advanced.

The goals of treatment are to first restore normal body weight and eating habits, and then to address the psychological issues.

A hospital stay may be needed if:

• The person has lost a lot of weight (below 30% of their ideal body weight for their age and height)
• Weight loss continues despite treatment
• Medical complications, such as heart rate problems, changes in mental status, low potassium levels, or mental status problems, develop
• The person has severe depression or thinks about committing suicide

Other treatment may include:

• Antidepressant drug therapy for depression
• Behavioral therapy
• Psychotherapy
• Supportive care

Severe and life-threatening malnutrition may require feedings through a vein.

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 good 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. However, most people with anorexia will continue to prefer a lower body weight and be preoccupied with food and calories to some extent. Weight management may be difficult, and long-term treatment may be necessary to help maintain a healthy body weight.

Complications can be severe. A hospital stay may be needed.

Complications may include:

• Appearance of fine baby-like body hair (lanugo)
• Bloating or edema
• Electrolyte imbalance (such as potassium insufficiency)
• Decrease in white blood cells which leads to increased risk of infection
• Heart arrhythmias
• Osteoporosis
• Severe dehydration, possibly leading to shock
• Severe malnutrition
• Seizures due to fluid loss from excessive diarrhea or vomiting
• Thyroid gland problems, which can lead to cold intolerance and constipation
• Tooth erosion and decay

Talk to your doctor if your child is restricting his or her food intake, over-exercising, or excessively preoccupied with weight. Getting early medical help before abnormal patterns are established can reduce the severity of an eating disorder.

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

Field AE, Javaras KM, Aneja P, Kitos N, Camargo CA Jr., Taylor CB, et al. Family, peer, and media predictors of becoming eating disordered. Arch Pediatr Adolesc Med. 2008;162:574-579.

Gowers SG. Management of eating disorders in children and adolescents. Arch Dis Child. 2008;93:331-334.

American Psychiatric Association. Treatment of patients with eating disorders, third edition. American Psychiatric Association. Am J Psychiatry. 2006 Jul;163(7 Suppl):4-54.

Bulik CM, Berkman ND, Brownley KA, Sedway JA, Lohr KN. Anorexia nervosa treatment: a systematic review of randomized controlled trials. Int J Eat Disord. 2007 May;40(4):310-20.

Morris J, Twaddle S. Anorexia nervosa. BMJ. 2007 Apr 28;334(7599):894-8.