Recognizing and Intervening in Pituitary Apoplexy

Elizabeth Zink, MS, ACNP, CCRN, CNRN

Disclosures

Topics in Advanced Practice Nursing eJournal. 2005;5(4) 

In This Article

Pathophysiology of Pituitary Apoplexy

Pituitary apoplexy describes any condition in which the pituitary gland becomes infarcted or hemorrhage occurs. The fundamental cause of this condition is a transient or sustained alteration in blood flow to the pituitary gland causing either hypoperfusion or hyperperfusion. The precise causes of pituitary apoplexy are not well understood. However, several etiologic theories have been offered for cases in which patients were found to have pituitary tumors or an enlarged pituitary gland without a tumor.

Infarction

In patients with or without a pituitary tumor, infarction of the pituitary gland may result from any event that causes systemic hypoperfusion.[7] For example, hypotension during a surgical procedure or septic shock put the pituitary gland at risk for ischemia and infarction. Episodes of increased intracranial pressure caused by coughing, sneezing, or positive pressure ventilation may also cause a transient reduction in pituitary blood flow sufficient to cause apoplexy.[7] The hypothalamic-hypophysial portal system is vulnerable to compression, which may result in hypoperfusion when intracranial pressure rises; the pituitary gland enlarges; or a tumor increases in size, creating a mass effect. In some rare cases, experts have suggested that the pituitary may enlarge so quickly or tumors develop so rapidly that the demands for blood flow exceed the local blood supply.[7]

Hemorrhage

Hemorrhage of the pituitary may occur as a result of reperfusion after infarction or as a primary hemorrhage. Possible mechanisms of primary hemorrhage include systemic anticoagulation, hyperperfusion of the pituitary, overstimulation caused by administration of exogenous adrenocorticotropic hormone (ACTH) during testing for adrenal responsiveness, or rupture of blood vessels made friable by tumor growth. Awareness of the possibility of pituitary pathology and apoplexy in the absence of a pre-established diagnosis of pituitary enlargement or tumor is important for identifying this small population of patients that may be helped greatly by rapid evaluation and neurologic or neurosurgical management.

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