Anorexia nervosa with elevated serum TSH.

Low or normal serum TSH concentration is common during fasting and in patients with anorexia nervosa. We report here four patients with anorexia nervosa who had elevated serum TSH, low T3 and low free T4 levels when the initial diagnosis was made. Also, an appearance of TSH peak in response to TRH was delayed, but T3 responsiveness to TRH was normal. All patients were clinically euthyroid with negative serum thyroid autoantibodies and without goiter. Following weight gain, basal levels of serum T3, free T4, and TSH, as well as TSH responsiveness to TRH, returned almost to normal. The data indicated that these patients with anorexia nervosa before refeeding had either a latent transient primary hypothyroidism or the low T3 syndrome associated with an inappropriately high secretion of TSH, probably a new condition that is related to their pretreatment nutritional state.