ELEVATED THYREOSTIMULIN IN HYPERTHYROIDIS M - A CASE OF PITUITARY RESISTANCE TO THYROID-HORMONES

Simultaneous elevation of thyreostimulin and thyroid hormones values, when associated with clinical hyperthyroidism, raises a dual problem o f diagnosis and treatment. We report a case of hyperthyroidism with el evated thyreostimulin in a young adult man. The values of free triiodo thyronin and free thyroxin were elevated and the thyroxin binding glob ulin was normal. A normal pituitary tomodensitometry, the normal value s of the alpha sub-unit of thyreostimulin and the dynamic tests of thy reostimulin secretion allowed us to rule out the hypothesis of a pitui tary adenoma. Non-tumoral inappropriate secretions of thyreostimulin a re at present regarded as syndromes of resistance to thyroid hormones. Their biological translation is a simultaneous elevation of thyreosti mulin and thyroid hormones. Peripheral resistance, which is rarely com plete, finds its expression in clinical hyperthyroidism or in normal c linical condition, whereas pituitary resistance, which causes the lack of feedback on the secretion of thyreostimulin expresses itself by cl inical hyperthyroidism, sometimes with goitre owing to the trophic act ion of thyreostimulin on the thyroid. Generalized syndromes of resista nce are the most common. Our patient had a selective pituitary resista nce to thyroid hormones and less than thirty cases are reported in the literature. Treatment with a beta-blocker remains indicated when faci ng clinical evidence for hyperthyroidism and oral triiodothyronin seem s to be able to slow down the inappropriate secretion of thyreostimuli n. Regarding our patient who experienced a clinical and biological rel apse after the stopping of the treatment, we join many authors who rec ommend a prolonged treatment.