後頭部痛のみで発症し，短期間に形態変化を示したためコイル塞栓術を施行した椎骨動脈解離性動脈瘤の1例

Vertebral Artery Dissecting Aneurysm Presenting with Isolated Pain and Showing Repeated Morphological Changes over the Short Term: A Case Report

Ⅰ．はじめに

　椎骨動脈解離性動脈瘤（vertebral artery dissecting aneurysm：VADA）は，後頭蓋窩の脳卒中の重要な原因の1つとして知られており，近年その報告数は増加しつつある³⁾．一般に，VADAはくも膜下出血にて発症する出血例と脳梗塞を生じる虚血例に大別されるが，疼痛のみで発症し経過する症例も少なからず存在する．過去の報告においてもその存在は知られていたが，本病態のみに注目した報告は少なく治療方針に苦慮することも多い^2,6,8,12,13)．今回われわれは，疼痛にて発症したVADAに対し，経過中にくも膜下出血や脳梗塞を認めなかったものの，短期間に形態変化を繰り返したため，血管内治療を施行し良好な経過を得た症例を経験したので報告する．

　Vertebral artery（VA）dissecting aneurysm（VADA），which presents with headache and neck pain as the only manifestations, is an uncommon pathology, but is increasingly recognized as a cause of posterior circulation stroke in young adults. We report a case of VADA with isolated occipital headache at the time of onset and treatment using an endovascular approach. A 58-year-old man was admitted to our hospital with left occipital headache. Cranial magnetic resonance imaging（MRI）showed neither subarachnoid hemorrhage（SAH）nor cerebral infarction, but magnetic resonance angiography（MRA）revealed left VADA. Conservative treatment including pain relief and blood pressure control was provided. After 2 weeks, the dissecting lesion showed spontaneous improvement and occipital headache was gradually improving. However, 4 months after onset, the VADA showed growing aneurysmal dilatation. We therefore performed endovascular surgery（coil embolization with parent artery occlusion). Symptoms improved, and the postoperative course was uneventful. Although the natural history of VADA with isolated headache remains unclear, endovascular treatment should be considered for patients with growing aneurysmal dilatation, since the prognosis for patients with subsequent SAH is very poor.