Pathogenesis of Cerebral Aneurysm

뇌동맥류의 병태생리

Cerebral aneurysms are common lesions. In most populations, the incidence of subarachnoid hemorrhage (SAH) is 10 per 100,000 personyears. The case fatality rate of SAH is about 50 percent in population-based studies, with a trend toward gradual improvement. Associated conditions include autosomal dominant polycystic kidney disease, fibromuscular dysplasia, Marfan's syndrome, Ehlers-Danlos syndrome, and arteriovenous malformations of the brain. The risk factors for the rupture of cerebral aneurysms include increasing size, specific site, smoking, and hypertension. Cerebral aneurysms can be divided into two different categories: saccular (atherosclerotic) and dissecting (nonatherosclerotic). The most common histologic finding in saccular aneurysms is a decrease in the tunica media, the middle muscular layer of the artery, causing structural defects. These defects combined with hemodynamic factors, lead to aneurysmal outpouchings at arterial branch points in the subarachnoid space at the base of the brain. Dissecting aneurysms are characterized by widespread disruption of the internal elastic lamina that leads to mural thrombus formation and causes ischemic or hemorrhagic symptoms. Ultimately, therapeutic strategies should be based on the epidemiology, natural history, and pathogenesis of the cerebral aneurysms.