Thyroid function in dietary amenorrhoea.

Abnormalities of thyroid function are well known to occur in anorexia nervosa. A commoner problem is the patient with secondary amenorrhoea due to weight loss, who does not have true anorexia nervosa. Eight such patients were studied and compared to a normal control group. Total and free thyroxine, total and free triiodothyronine were found to be significantly lower in the amenorrhoea patients. No difference in basal thyroid stimulating hormone or reverse triiodothyronine levels were found. In three of four patients who had thyrotrophin releasing hormone tests performed a prolonged response was found. These results indicate that abnormal thyroid function tests may be found in this milder form of the disease. In addition, the normal reverse triiodothyronine levels suggest the possibility of two mechanisms existing, whereby T3 levels may be lowered in nutritional disorders.