Overview of Pituitary Stroke
Pituitary crisis is pituitary stroke. Acute neuroendocrine lesions caused by sudden intratumoral hemorrhage, infarction, and necrosis of pituitary tumors, resulting in enlargement of the tumor, are called pituitary strokes. The clinical manifestations of acute pituitary stroke mainly depend on the direction of tumor expansion and the degree of hemorrhage and pituitary destruction. The hemorrhage is rapid and large, directly affecting the hypothalamus, and the patient may be accompanied by cerebral edema and obvious increase in intracranial pressure.
Etiology
The exact cause of pituitary stroke is not clear, most of the causes cannot be found, and it is currently believed that it may be related to the following factors.
1. Ischemic factors
(1) When the growth of pituitary adenoma exceeds the blood supply capacity, an ischemic necrotic area occurs in the tumor tissue, followed by hemorrhage.
(2) The pituitary gland is supplied through the pituitary portal system from the pituitary stalk. When a pituitary adenoma grows toward the saddle, it can be embedded in the middle narrow part of the saddle-diaphragmatic incision and the pituitary stalk, blocking the nutritive blood vessels of the distal part of the pituitary gland and the tumor, resulting in ischemia, necrosis, and hemorrhage of the entire anterior lobe and the tumor. Pituitary adenomas grow laterally to compress the cavernous sinus, and exogenous factors increase cavernous sinus pressure. It causes increased venous pressure within the tumor and infarcts the arteries supplying the tumor with damage.
2.Vascular factors
Pituitary adenoma is rich in blood vessels, forming irregular blood sinus, and the wall of blood sinus is thin, and the increase in tumor volume causes the local pressure to increase, resulting in blood vessel rupture and bleeding.
Symptoms
Pituitary stroke mainly manifests as meningeal irritation caused by severe hemorrhage and compression of surrounding tissues. The clinical manifestations of acute pituitary stroke mainly depend on the direction of tumor expansion and the degree of hemorrhage and pituitary destruction. If the hemorrhage is rapid and large, directly affecting the hypothalamus, the patient may be accompanied by cerebral edema and obvious increase in intracranial pressure, visual field impairment, progressive aggravation of impaired consciousness until coma or even death. If it affects other outcomes, it may also manifest as headache, visual field impairment, ocular muscle paralysis or impaired consciousness.
Subacute pituitary strokes may have a milder clinical picture, with only visual disturbances or ocular muscle paralysis due to slower hemorrhage, mild aggravation of pre-existing pituitary adenomas, and no signs of meningeal irritation or impaired consciousness. Chronic pituitary stroke has small amount of hemorrhage, no compression of peripheral tissue structures, and no clinical symptoms other than those of the original pituitary adenoma, which is often detected by CT, MRI or surgery.
Examination
Imaging examination is of great significance for the diagnosis and differential diagnosis of pituitary stroke.
1. X-ray examination
X-ray film can find that the pterygoid saddle is enlarged, the anterior bed process disappears, and the saddle base is thinned or destroyed.
2.CT scan
CT scan can show low density (edema or necrosis) or high density (hemorrhage), and the tumor can show peripheral enhancement after injection of contrast medium.CT scan can clarify the spread of subarachnoid hemorrhage and whether it is expanding to the ventricle, and it can diagnose the course and time of the hemorrhage of pituitary adenomas and it has a certain value of reference for the selection of the surgical access.
3. Cerebral angiography.
4.MRI examination
When pituitary stroke occurs, on T1 and T2 weighted images, it can show a high signal area in the lesion.
Diagnosis
Pituitary stroke can be diagnosed by combining clinical manifestations and laboratory tests. Pituitary stroke may also affect the secretion of various hormones in the anterior pituitary gland, which may cause mucoedema coma and adrenal crisis.
Differential diagnosis
Pituitary stroke should be differentiated from subarachnoid hemorrhage, bacterial meningitis, cerebral hemorrhage, cerebral infarction, metastatic tumor of pituitary gland, optic cross stroke, posterior bulbar optic neuritis and other diseases.
Complications
Pituitary stroke can exacerbate pre-existing adenopituitary hypoplasia. Bleeding causes compression of the pituitary stalk, which reduces PRL inhibitory factors reaching the adenopituitary gland and can also lead to elevated PRL levels. Pathologic examination confirms that neuropituitary involvement is common, but the presence of uremia is rare. A few patients develop syndrome of inappropriate secretion of antidiuretic hormone (SIADH) due to hypothalamic involvement.
Treatment
The clinical course of pituitary stroke is often unpredictable. Upon diagnosis, hormone replacement therapy should be given immediately to maintain water-electrolyte balance to enhance stress capacity and reduce acute edema in the optic nerve and inferior optic chiasm, to stabilize clinical symptoms, to reduce surgical morbidity and mortality, and to consider surgical treatment.
Prognosis
Arteriosclerosis may cause degenerative lesions of the blood vessels in the pituitary gland, and the resistance of the blood vessels to injury is weakened, and in some cases, intra-pituitary hemorrhage may occur; because of the slow blood flow and elevated blood viscosity in arteriosclerotic patients, thrombus is easy to be formed in the pituitary gland, which may lead to infarction of the pituitary gland.
If combined with hypertension, the patient is more likely to have a pituitary stroke. Diabetes mellitus can also cause pituitary stroke due to degenerative lesions of the pituitary blood vessels.
Prevention
Radiation therapy is not recommended in the acute stage. Antibiotics can be used to prevent infection in severe cases.