ウイリス動脈輪閉塞症の病態

-出血源としてのmiliary aneurysmの発生と若年・成人両型における発生頻度に関する拡大脳血管撮影による検討-

抄録

The spontaneous occlusion of the circle of Willis occurs in a juvenile group and an adult one. The authors proposed a hypothesis that the symptoms belong to one disease entity which appears in a juvenile stage and, after an asymptomatic period, reappears in an adult stage as a hemorrhagic type. For proving the hypothesis, the authors tried to find a relation between both groups. At first the hemorrhagic source of intracranial hemorrhage in the adult group was investigated to decide when the symptom appeared and show the difference in the pathological conditions of both groups. The authors employed serial cerebral magnification besides conventional cerebral angiography, and precisely observed the cerebral vasculature in each age stage with magnification rentogenography. The 24 cases with spontaneous occlusion of the circle of Willis examined in this work consisted of 11 cases of the juvenile group and 13 cases of the adult one. In 7 cases of the latter which were diagnosed as subarachnoidal hemorrhage and subject to CT examination soon after the diagnosis, 3 cases had miliary aneurysm of less than 1mm diameter in the basal abnormal vascular network (Table 1). Also small aneurysms greater than 1mm in diameter were found in the anterior and posterior choroidal arteries in 3 cases (Table 2). Magnification cerebral angiography showed that the incidence of miliary aneurysm was low in 3 cases of the juvenile group: the incidence of small aneurysms greater than 1mm in diameter was 1/11 in the juvenile group and 4/13 (31%) in the adult group. Since intracranial hemorrhage due to the rupture of small aneurysms has been reported, the miliary aneurysm must be noted as an important source of hemorrhage. The fact that the incidence in the juvenile group is lower than that in the adult one suggests the increase of aneurysm with aging; it will explain the difference of the incidence of intracranial hemorrhage between both groups. And the result suggests that the disease will progressively change its pathological conditions from juvenile group to adult one and the disease belong to one disease entity.