Significance of intracranial aneurysms associated with moyamoya disease. (Part II). Cause and site of hemorrhage--review of the literature

Abstract

The intracranial aneurysms associated with Moyamoya disease were analyzed on the basis of the origin and location of the hemorrhage. The study was performed using 41 cases collected from the literature including a case of the authors' own. Of the 41, 27 were cases of bilateral Moyamoya disease with intracranial hemorrhage, 9 of unilateral Moyamoya disease, and 5 of unidentified Moyamoya disease, in which it remained unknown whether the Moyamoya vessel was unilateral or bilateral. This report used the diagnostic criteria adopted by the research team of the Japanese Ministry of Health and Welfare for the Moyamoya disease. The definition of the aneurysm was limited to one with a size greater than 1 mm in maximum diameter, confirmed by angiography, operation, or autopsy. Among the 13 cases of Moyamoya disease with major artery aneurysms, the origin of the hemorrhage was the aneurysm in 3 cases, Moyamoya vessels in 3, and unknown in 7. Primary subarachnoid hemorrhage (SAH) occurred in all the cases in which aneurysm was the origin of the hemorrhage. Of the 14 Moyamoya disease cases with peripheral artery aneurysms, the origin of the hemorrhage was aneurysm in 6 cases, Moyamoya vessels in 1, and unknown in 7. Intracerebral or intraventricular hemorrhage occurred in all the 6 cases in which the origin of hemorrhage was peripheral artery aneurysm. These findings suggested that the original hemorrhage was caused as a result of a rupture of the intracranial aneurysm with the Moyamoya disease and they were divided into three groups according to the hemorrhage site: 1) major artery aneurysms which caused the primary SAH just like the usual saccular aneurysms, 2) basal ganglia aneurysms which caused intracerebral or intraventricular hemorrhage, and 3) other anastomotic vessel aneurysms which might cause the primary SAH, though not previously reported. It was also assumed that in the Moyamoya disease without the aneurysm or with the unruptured aneurysm, the intracranial hemorrhage occurred as a result of a rupture of the peripheral portion of the perforating artery which constituted the Moyamoya vessels, and the hemorrhage was located in the intracerebral or intraventricular regions.