Intrasellar Pressure Research Articles

Hyperprolactinaemia in patients with pituitary adenomas. The pituitary stalk compression syndrome

Hyperprolactinaemia, unexplained by prolactin-production of the tumour is occasionally found in patients with pituitary tumours. This secondary hyperprolactinaemia has been ascribed to a mass effect of the tumour upon the pituitary stalk, obstructing the normal inhibitory hypothalamic influence on the prolactin producing cells. In this study the adenoma volume, amount of suprasellar enlargement of the tumour and the intrasellar pressure were measured in 42 patients operated upon consecutively for pituitary tumours. Secondary hyperprolactinaemia was found in six (14%). There was no difference as regards adenoma volume, amount of suprasellar extension or intrasellar pressure between the group of patients with elevated p-prolactin versus the group with normal p-prolactin. We conclude that mechanisms other than pituitary stalk compression must be considered as the cause of secondary hyperprolactinaemia.

Pressure and blood flow in pituitary adenomas measured during transsphenoidal surgery.

In 48 patients undergoing transsphenoidal surgery for pituitary adenoma, the intrasellar pressure was recorded during surgery. In 14 patients, adenoma blood flow was measured with the technique of local injection of 133xenon. Median intrasellar pressure was 30 mmHg (range 8-62), n = 48, and median adenoma blood flow was 8 ml/100 g/min (range 0-37), n = 14. In two patients, blood flow in the anterior pituitary gland was measured, and values of 26 and 22 ml/100 g/min were obtained. The finding that intrasellar pressure is above central venous and intracranial pressure suggests the possibility that the adenoma and the anterior pituitary gland are supplied not only with venous blood, but receive an additional arterial supply at a less than normal arterial pressure. In three cases perfusion pressures that caused arrest of adenoma blood flow were found, and these observations are discussed with reference to pituitary apoplexy.

Hyperprolactinemia, intrasellar pituitary tissue pressure, and the pituitary stalk compression syndrome.

The intrasellar pressure has been studied in a consecutive series of 24 patients undergoing transsphenoidal surgery for pituitary adenoma. The mean intrasellar pressure for the group was 23 +/- 2.5 mm Hg (+/- standard error of the mean), with a mean pulse pressure of 3.5 +/- 1 mm Hg. The waveform partly resembled the arterial configuration. The results are correlated with the radiological and endocrinological features of the tumors. A hypothesis is proposed to explain the mechanism of hyperprolactinemia associated with the pituitary stalk compression syndrome.