Apoplexy of a pituitary adenoma after dynamic testing with gonadotropin-releasing hormone

Abstract

Pituitary tumor apoplexy is a rare clinical syndrome characterized by hemorrhagic infarction of a pre-existing adenoma followed by the acute onset of headache, vomiting, visual disturbances, and sometimes alteration in the level of consciousness [l-3]. Although the pathophysiology of its development is not known, there are some apparent precipitating factors as recently summarized by Ebersold et al [4]. A few recent reports described the occurrence of apoplexy after dynamic testing of anterior pituitary function [5-71. In all of these instances, the apoplectic episode occurred after the combined administration of thyrotropin-releasing hormone (TRH) and gonadotropin-releasing hormone (GnRH), insulin, or glucagon. Although GnRH is commonly used in the dynamic testing of pituitary gonadotropin secretion, there are, to our knowledge, no known serious neurologic complications associated with its use. Apoplexy has never been reported to occur after the single injection of this hypothalamic-releasing factor. In this report, we describe a patient with hyperprolactinemia in association with a pituitary macroadenoma who developed hemorrhagic infarction of the adenoma following the intravenous administration of GnRH. The patient had an uneventful recovery after transsphenoidal removal of the necrotic tumor. CASE REPORT A 41-year-old woman presented with a five-year history of amenorrhea. Three years before admission, she had an elevated serum prolactin level to 75 ng/mL and a demonstrable pituitary adenoma on computed tomography. No treatment was given at that time and the patient was next seen by us for endocrine evaluation. She had remained amenorrheic, but exhibited no findings to suggest hypopituitarism, and had no visual disturbances or headaches. Except for a minimal clear discharge from both breasts, results of physical examination were unremarkable. Initial studies showed elevated serum prolactin and follicle-stimulating hormone (FSH) levels (Table I). Magnetic resonance imaging (MRI) of the sella turcica showed a macroadenoma with extension into the suprasellar region and superior displacement of the optic chiasm. Determination of the gonadotropin responses of GnRH was planned in view of the known elevation of the basal FSH level. Approximately 60 minutes after the administration of GnRH (100 pg intravenously), the patient noted the sudden onset of headache, which