Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
The term “pituitary apoplexy” (PA) was first described in context of five autopsies in which hemorrhagic necrosis was noted in pituitary adenomas; the studied patients had a history of clinical dyspituitarism and sudden death . This condition is exceptionally rare relative to the frequency of pituitary adenomas; 0.6–9% of adenomas undergo clinical apoplexy while up to 20–25% of the general population may have pituitary tumors or cysts of variable size . Although patients have been known to present up to 14 days after the onset of apoplectic symptoms, their clinical deterioration may have begun prior to this event . Unfortunately, most patients have pituitary tumors unbeknown to them because they do not have access to primary care physicians due to the lack of health insurance . Therefore, many of these patients could avoid catastrophic neurological and endocrinological decline.
Radiographically, hemorrhage within the sella is not specific to pituitary apoplexy. Hemorrhage in this location can be seen in other pathological conditions, such as Sheehan’s syndrome, metastases, trauma, and coagulopathic states. When apoplexy occurs in the setting of a pituitary adenoma, both ischemia and hemorrhage are usually observed . Typically, an enlarging adenoma with increased metabolic requirement can outstrip its arterial supply leading to necrosis or the tumor can compress its draining veins causing a venous infarct ; owing to this latter theory, engorgement of sphenoid sinus mucosa due to venous hypertension has been radiographically appreciated prior to apoplexy . Others have hypothesized that the hemorrhagic event is associated with the intrinsic friability of tumor vessels with incomplete basal membranes or with atherosclerotic emboli . Based on the authors’ experience, the majority of the surgical cases seem to have a direct association to decreased venous drainage into the cavernous sinus with subsequent venous congestion followed by venous infarct. A hemorrhagic component may or may not be associated to the event and most likely depends on the severity of the venous congestion. Needless to say, there is disagreement regarding the etiology of pituitary apoplexy.
The general risk factors for apoplexy include acute increase or decrease in hypophyseal blood flow, hormone modulation from exogenous or endogenous sources, surgery (particularly cardiac), and anticoagulation . Hypertension has been shown to be associated with apoplectic events and has been seen in about one-quarter of patients . Alterations in intracranial pressure or systemic hypotension, which can be induced during cardiac surgery, can also cause changes in the portal circulation . An increase in circulating hormones from stress or the use of dopamine agonists can lead to the same outcome . However, most cases of apoplexy occur without any documented, precipitating factor . Most often, this condition is seen in adults with null-cell adenomas and 80% of patients have no documented history of an adenoma upon presentation .
Become a Clinical Tree membership for Full access and enjoy Unlimited articles
If you are a member. Log in here