INVESTIGATIONS

INVESTIGATIONS OF ANOREXIA NERVOSA

Anorexia Nervosa is mostly a clinical diagnosis and therefore not many specific diagnostic tests are available.
Commonly, the diagnosis is made by a good history taken and assessment of the individual of the DSM-IV TR (Diagnostic and Statistical Manual of Mental Disorders IV)

The diagnostic criteria for anorexia nervosa in the DSM-IV TR are as follow:
1. A refusal to maintain body weight at or above a minimally normal weight for age and height (usually 85% of ideal body weight)
2. Intense fear of gaining weight or becoming fat
3. Disturbance in the way one’s body weight or shape is experienced, with denial of low body weight
4. Amenorrhea in postmenarchal females of at least 3 menstrual cycles

However new recommendations are made to revise the amenorrhea in the new DSM-V.
There are two subtypes of anorexia nervosa:
I. Restricting: in which severe limitation of food intake is primary means to weight loss
II. Binge eating/purging type: periods of excessive food intake that are compensated by self-induced vomiting, laxative or diuretic abuse and/or excessive exercise (bulimia nervosa)

Often individuals with AN have such personality traits: desire for perfection, OCD, social isolation, academic success, lack of age-appropriate sexual activity, denial of hunger in face of starvation, excessive dependency needs and more.
AN is a complex interplay between biopsychosocial factors and affects women more than men. Some neurobiologist do mention that serotonergic pathways in the brain mediate the development of AN.

Malnutrition from self starvation leads to protein deficiency and disruption of multiple organ systems. In addition to hypoglycaemia and vitamin deficiencies, starvation results in release of endogenous opioid, hypercortisolemia, and thyroid function suppression. Neuroendocrine disturbances result in delayed puberty, amenorrhea, anovulation, low oestrogen levels, increased growth hormone, decrease ADH, hypercarotenemia, and hypothermia.

Cardiovascular: mitral valve prolapse, supraventricular and ventricular dysrhythmias, long QT syndrome, bradycardia, orthostatic hypotension, and shock due to congestive heart failure

Renal: decreased glomerular flitration rates, edema, acidosis with dehydration, hypokaelmia

GIT: constipation, delayed gastric emptying, rupture when binge eating

LAB TESTS
1. FBC
2. Perform urinalysis
3. Blood chemistry analysis
4. Hyponatremia reflects excessive water intake or inappropriate secretion of ADH (normal range: 135-145 mmol/L)
5. Hypoglycaemia results from lack of glucose precursors in the diet or low glycogen stores (<6.1mmol/l,>
6. Renal function normally normal except for patients with dehydration, would show higher BUN levels (blood urea nitrogen) [7-18mg/dL]
7. Protein and albumin are usually normal, probably due to intake of high quality proteins
8. Liver function slightly elevated
9. Dramatic cholesterol elevations
10. Leukopenia and thrombocytopenia observed
11. Haemoglobin levels are usually normal though elevations are observed in states of dehydration
12. ESR is normal, elevations should prompt an organic etiology

OTHER TESTS
Cardiovascular complications account for the most morbidity and mortality
An ECG is helpful in evaluating a prolonged QT interval, findings might show a low voltage, prolonged QTc and nonspecific T-wave changes. In patients with prolonged QT, potentially harmful dysrhythmias are possible

STAGING
- Early or mild staging: mildly distorted body image, weight 90% or less of average weight for height, no symptoms or signs of excessive weight loss. Use of potentially harmful weight control methods for a strong drive to lose weight
- Established or moderate stage features include the following: definitely distorted body image that has not diminished with weight loss, 85% of average weight for height and refusal to gain weight, unhealthy means to lose weight, eating less than 1000 calories per day, purging or excessive exercise


FOR ANY OTHER NORMAL VALUES OR RANGES OF TESTS, REFER TO:
http://www.bloodbook.com/ranges.html