Anorexia nervosa is particularly characteristic of young women. This type of eating disorder has been diagnosed since 17th century. In 1990, it has been a salutary thought that it is more dangerous to be a fashion model in a ballet school rather than working at a coal miner. This reflects the high level of mortality and morbidity in people having anorexia nervosa in comparison with people with other types of psychiatric condition.
Prevalence in females: males = 20:1 and usually associated with depression and bulimia at later age. Prevalence of bulimia and anorexia is about 5-10% of young women and the risk increase with background history of addictive disorders.
Diagnostic criteria:
- Refusal to maintain body weight at or minimally normal ideal weight for a person by her/his sex, age and height (e.g.: weight loss or failure to make expected weight gain during period of growth, leading to body weight <85% expected)
- Regardless the fact that he/she is underweight, he/she is still having the intense fear of gaining weight or becoming fat.
- There is disturbance in perception of body weight or shape on self evaluation, denial of the seriousness of the current low body weight
- Amenorrhea (no menstruation) in young women that previously has menses (post menarchal)
Signs and symptoms:
- Weight loss of 25% of body weight (or more)
- Onset usually before 17 years old
- Laxative use
- Diuretic use
- Excessive exercising
- Amenorrhea – develop early when <90% ideal body weight (IBW=100lb@60 inch, +5lb for each inch after that)
- Always think self too fat (no matter how thin he/she is)
- Secretive eating
- Lanugo hair maybe found (usually only seen in babies)
- Self appearance is thin and sometimes chacectic
Investigations:
- FBC – to look for evidence of anemia
- BUSE – to look for electrolyte imbalance à hypokalemia (low potassium), hypophosphatemia (low phosphate). In laxative use, the result usually normal anion gap acidosis.
- Serum amylase – usually elevated, sometimes due to pancreatitis but most of the times due to salivary origin (lipase and pancreatic fraction is normal)
- ECG or EKG at some regular interval to detect myocardiopathy or long QT syndrome
Complications:
- Suicide (in 2-5% of cases)
- Depression
- Osteoporosis or bone loss
- Cardiac heart failure ( due to prolonged starvation)
- Addison’s disease need to be ruled out
- 50% of all cases may progress to chronic bulimia
- 9% mortality
Treatment:
- The only effective treatment is behavioral therapy (either inpatient or outpatient)
- Calcium and vitamin D supplement to prevent osteoporosis
- Periactin
- Consider leptin injections for amenorrhea
Reference:
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- Quick Reference Cards by Medical Protection Society. 2001.
- The Little Black Book of primary Care. Daniel K. Onion. 5th edition. 2006.
- Psychology and sociology applied to medicine. Churchill Livingston. Mike Porter et al, 1999.
