Infarction of a growth hormone-secreting macroadenoma during a TRH test

Pituitary infarction occurring immediately after TRH injection (200 micrograms) is reported in a patient with gigantism due to a growth hormone-secreting pituitary macroadenoma. Evidence of infarction was seen in CSF and in serial CT scans. Regression of symptoms and sign of acromegaly, abolition of abnormal growth hormone secretion, and virtually complete anterior and partial posterior pituitary failure rapidly followed. The infarction was probably initiated by a hypertensive response to TRH. TRH testing in acromegalic subjects may require smaller doses of TRH to avoid unwanted pressor responses.