Kojima A, Nakamura T, Takayama H, Harada S, Takamiya Y
Department of Neurosurgery, Saiseikai Kanagawa Prefectural Hospital, Japan.
No Shinkei Geka. 1996 May;24(5):469-73.
A case is presented of a de novo aneurysm of the distal posterior inferior cerebellar artery with intraventricular hemorrhage. A 67-year-old woman was admitted to our hospital with sudden onset of severe headache and loss of consciousness. Computed tomography (CT) scans showed subarachnoid hemorrhage. Angiography demonstrated three aneurysms: an aneurysm of the right vertebral-posterior inferior cerebellar artery, an aneurysm of the bifurcation of the basilar artery, and an aneurysm of the left middle cerebral artery. Considering the distribution of the hemorrhage on CT scans, we concluded that the cause of the hemorrhage was rupture of the vertebral-posterior inferior cerebellar aneurysm. The vertebral-posterior inferior cerebellar aneurysm and the middle cerebral aneurysm were successfully clipped, postoperative angiograms showing the complete clippings. At that time, however, there were no abnormal findings in the left posterior inferior cerebellar artery. Six years later, she was readmitted to our hospital because of sudden onset of headache, nausea, and vertigo. CT scans showed an intraventricular hemorrhage, especially in the fourth ventricle, although subarachnoid hemorrhage was not clearly found. Angiography revealed an aneurysm of the left distal posterior inferior cerebellar artery. She underwent clipping of the aneurysm verified by postoperative angiograms. However she had bacterial meningitis and died from pneumonia and disseminated intravascular coagulopathy. De novo aneurysms of the anterior circulation have often been reported. Carotid, ligation, smoking, the use of oral contraceptives, congenital anomalies and hypertension are major risk factors in the formation of aneurysms. A de novo aneurysm of the distal posterior inferior cerebellar artery is, however, extremely rare. In this case, the right posterior inferior cerebellar artery disappeared when the de novo aneurysm was found. So it is supposed that hemodynamic changes caused by the clipping of the right vertebral-posterior inferior cerebellar aneurysm and the left middle cerebral aneurysm had contributed to the formation of the de novo aneurysm of the left distal posterior inferior cerebellar artery. In the present study, we review the literature on the aneurysm at the distal posterior inferior cerebellar artery and on the de novo aneurysm of the vertebrobasilar artery, and discuss the radiological findings and features.
本文报告一例伴有脑室内出血的小脑后下动脉远端新发动脉瘤病例。一名67岁女性因突发剧烈头痛和意识丧失入院。计算机断层扫描（CT）显示蛛网膜下腔出血。血管造影显示三个动脉瘤：右侧椎动脉-小脑后下动脉瘤、基底动脉分叉处动脉瘤和左侧大脑中动脉瘤。根据CT扫描上出血的分布情况，我们得出出血原因是椎动脉-小脑后下动脉瘤破裂。椎动脉-小脑后下动脉瘤和大脑中动脉瘤成功夹闭，术后血管造影显示夹闭完全。然而，当时左侧小脑后下动脉未见异常。六年后，她因突发头痛、恶心和眩晕再次入院。CT扫描显示脑室内出血，尤其是第四脑室，尽管未明确发现蛛网膜下腔出血。血管造影显示左侧小脑后下动脉远端有一个动脉瘤。她接受了动脉瘤夹闭术，术后血管造影证实夹闭成功。然而，她发生了细菌性脑膜炎，最终死于肺炎和弥散性血管内凝血。前循环新发动脉瘤常有报道。颈动脉结扎、吸烟、口服避孕药的使用、先天性异常和高血压是动脉瘤形成的主要危险因素。然而，小脑后下动脉远端新发动脉瘤极为罕见。在本病例中，发现新发动脉瘤时右侧小脑后下动脉消失。因此推测，右侧椎动脉-小脑后下动脉瘤和左侧大脑中动脉瘤夹闭引起的血流动力学改变促成了左侧小脑后下动脉远端新发动脉瘤的形成。在本研究中，我们回顾了关于小脑后下动脉远端动脉瘤和椎基底动脉新发动脉瘤的文献，并讨论了影像学表现和特征。
