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Cerebrovascular Disorders
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Essentials of Diagnosis
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- Headaches, visual disturbances, syncope, and hemiparesis are among the most common presenting findings.
- Computed tomography scan and magnetic resonance imaging can be used in pregnancy to increase the delineation of cerebrovascular involvement. Arteriography is considered definitive if surgical intervention is being considered because arteriography can more precisely localize the involved area.
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The causes of cerebrovascular disease include insufficiency (arteriosclerosis, cerebral embolism, vasospasm from hypertensive disease) and disorders associated with bleeding into the cerebral cortex (arteriovenous malformation, ruptured aneurysm). The brain becomes infarcted from lack of blood flow, or intracranial bleeding results in a space-occupying lesion. The severity of such disorders can be affected by blood pressure, oxygen saturation (anemia or polycythemia), hypoglycemia, and adequacy of collateral circulation.
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The overall incidence of ischemic cerebrovascular accidents in pregnancy is approximately 1 in 20,000 births, with most occurring in the last trimester or immediately postpartum. Etiologic factors for stroke include cardioembolic disorders, cerebral angiopathies, hematologic disorders, and cerebral vein thrombosis. Causes exclusive to pregnancy are eclampsia, choriocarcinoma, and amniotic fluid embolism. Although cerebral ischemic disease can occur in either the arterial or venous system, approximately 75% of occlusive cerebral disease occurs on the arterial side.
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Cerebrovascular accidents involving subarachnoid hemorrhage or intraparenchymal hemorrhage similarly occur at a rate of 1 in 20,000 births. These events usually are the result of aneurysms or arteriovenous malformations. The most common aneurysm is the saccular (berry) variety, which protrudes from the major arteries in the circle of Willis, particularly at its bifurcations. Aneurysms have an increasing tendency to bleed as the pregnancy progresses, likely due to changes in hemodynamic factors. Rupture of arteriovenous malformations has been found to occur evenly throughout gestation. No consensus has been reached regarding the increased frequency of bleeding from either an aneurysm or arteriovenous malformation during pregnancy or the immediate postpartum period. Rupture of the malformation appears to be more frequent during pregnancy. Eclampsia can lead to cerebral hemorrhage when elevated blood pressures lead to vasospasm, loss of autoregulatory function, and rupture of the vessel wall.
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Headaches, visual disturbances, syncope, and hemiparesis are among the most common presenting findings. The pattern of clinical signs and symptoms generally allows recognition of the area of the brain involved. Computed tomography (CT) scan and magnetic resonance imaging (MRI) can be used in pregnancy to increase the delineation of cerebrovascular involvement. Arteriography is considered definitive if surgical intervention is being considered because arteriography can more precisely localize the involved area. Because coagulopathies can also cause intracranial bleeding or may be secondary to the cerebrovascular lesion itself, a coagulation profile should be performed. Additionally, antinuclear antibody (ANA), lupus anticoagulant, factor V Leiden, homocysteine, anticardiolipin, proteins C and S, antithrombin III, and plasminogen levels should be considered with thrombotic cerebral events.
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