Pituitary apoplexy in acromegaly, a long-term follow-up study in two patients.

Pituitary apoplexy is a serious complication in about 3% of patients with a pituitary adenoma. Very often, the diagnosis of a functioning or non-functioning adenoma is made in retrospect. In this report, we describe two patients in whom the diagnosis of acromegaly was made before the apoplexy. In one patient, surgical intervention was necessary because of remaining clinical and biochemical activity; in the other patient conservative follow-up was pursued. Seven and nine years after apoplexy, respectively, the patients were clinically and biochemically in remission. During the follow-up, three and five years after apoplexy, respectively, the patients underwent a 10-min venous sampling procedure for 24 hours, and the GH secretory profile was investigated with multiparameter deconvolution analysis and by approximate entropy (ApEn), a scale- and model-independent regularity measure. The deconvolution analysis revealed an increased basal (nonpulsatile) GH secretion rate, while the total 24 h secretion rate was normal compared with 13 healthy male control subjects. ApEn was much larger for each patient than for any control subject value, indicating markedly more irregular GH secretion. We hypothesize that these subtle abnormalities are caused by non-specific damage as a result of vascular insult, leading to abnormal vascular supply, or abnormal autocrine and paracrine GH regulation within the remaining gland.