突発する後頸部痛4日後にくも膜下出血をきたした解離性椎骨動脈瘤の1例

A Case of Vertebral Dissecting Aneurysm Manifesting as Subarachnoid Hemorrhage Following Nuchal Pain

要旨　血管解離に起因する後頸部痛4日後に，くも膜下出血（SAH）をきたした解離性椎骨動脈瘤の1例を報告した。症例は46歳男性で，突発する後頸部痛のため他院にてMRIを施行された。明らかな異常は指摘されず経過観察されたが，その4日後に再度，突発する後頸部痛をきたし当院へ搬送された。頭部CTではSAHを認め，脳血管撮影にて解離性右椎骨動脈瘤と診断し，血管内治療による再出血防止を行った。前医にて撮影されたMRIでは，右椎骨動脈に壁内血腫を伴う動脈瘤様拡張を認めたことより，当初の後頸部痛は解離痛であった可能性が強く示唆された。文献では，解離痛のみで発症する解離性椎骨動脈瘤の頻度は7％と報告されている。しかし，その後にSAHを併発する症例の予後は致死的であることより，解離痛のみで発症する非出血型解離性動脈瘤の存在を念頭に置いた頭痛・後頸部痛の原因検索が重要である。

We report a case of subarachnoid hemorrhage（SAH） from vertebral dissecting aneurysm 4 days after first nuchal pain. The patient was a 46-year-old man with a sudden onset of nuchal pain. There were no obvious abnormalities detected on MR images in another hospital. Four days later, however, he was admitted to our hospital because of severe re-attack of nuchal pain. CT demonstrated moderate SAH and cerebral angiograms revealed right vertebral dissecting aneurysm. Proximal occlusion of the vertebral artery including its aneurysmal dilatation was performed using detachable coils. We strongly suspected that his initial symptom of nuchal pain was due to dissection of the vertebral artery itself, since the aneurysmal dilatation accompanied by intramural hematoma had been observed retrospectively in the initial MR imaging. The incidence of the vertebral dissecting aneurysm presenting with nuchal pain alone due to dissection is reported to be 7％ in the literature. The prognosis of non-hemorrhagic vertebral dissecting aneurysm followed by delayed SAH is considered to be fatal. Therefore, careful investigations for differential diagnosis should be taken into account since the diagnostic possibility exists that non-hemorrhagic vertebral dissecting aneurysm would be manifested by a symptom of headache/nuchal pain alone.