Abstract
A 37-yr-old woman with recurrent hyperthyroidism after partial thyroid ablation was found to have an enlarged sella turcica and elevated serum thyrotropin (TSH) and prolactin (PRL) levels measured by radioimmunoassay. Serum growth hormone (GH), luteinizing hormone (LH), follicle-stimulating hormone (FSH), and cortisol levels were within normal limits and responded appropriately to provocative stimuli both before and after surgery. Preoperatively, the administration of thyrotropin-releasing hormone (TRH) (200 μg i.v.) and metoclopramide (MCP) (10 mg p.o.) induced a more than twofold increase in serum PRL levels, whereas TSH was only modestly affected. Bromocriptine (2.5 mg p.o.) and l-dopa (500 mg p.o.) suppressed TSH and PRL values to less than 50% of their initial values. After selective transsphenoidal removal of a pituitary adenoma, signs and symptoms of hyperthyroidism disappeared and TSH and PRL returned to normal. The postoperative administration of TRH and MCP produced a normal response for both PRL and TSH. Postoperatively, bromocriptine induced a parallel decrease in the serum level of both hormones, whereas l-dopa decreased PRL but had no effect on the serum TSH level. This case provides evidence that hyperthyroidism caused by a pituitary adenoma can be successfully treated by transsphenoidal surgery with preservation of normal pituitary function and reserve.
Published Version
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