細菌性外頚動脈瘤の1例

A Case of Bacterial Aneurysm that Occurred in the External Carotid Artery

Ⅰ．は じ め に

　細菌性動脈瘤は菌塊を含む塞栓子が血管を閉塞し，その部分の血管壁で増殖，壁破壊を起こして生じると考えられているため，一般に塞栓子が詰まりやすい末梢血管に形成されやすいといわれている．実際に細菌性動脈瘤が頭蓋外の頸動脈に発生することは稀であり，われわれの渉猟し得た範囲では53例のみの報告であった．これらは1例を除いて内頸動脈に形成されており，外頸動脈に生じた細菌性動脈瘤は極めて稀である．

　今回われわれは，感染性心内膜炎に合併した頭蓋外外頸動脈瘤を経験したので文献的な考察を加えて報告する．

Occurrence of a mycotic aneurysm extracranially is extremely rare. We report our experience with a case of mycotic aneurysm that occurred in the external carotid artery accompanying infectious endocarditis.

　The case was a 33-year-old male. He visited our hospital with principal complaints of weakness in the lower left side and visual difficulty. Multiple cerebral infarctions were noted in a head MRI. In addition,vegetation was noted on the mitral valve in an echocardiogram,and the patient was admitted to cardiology for infectious endocarditis. Aneurysms were noted in the external carotid artery and the posterior cerebral artery in a cerebral angiogram performed before valve replacement. After administration of antibiotics for 5 weeks,radical surgery was performed for the external carotid artery aneurysm that had remained unchanged. With a satisfactory postoperative course,the patient was able to walk independently after mitral valve replacement and was discharged.

　We have scoured the literature with regard to mycotic aneurysm occurring extracranially and have studied this case because of this characteristic. When performing cerebral angiography to search for a mycotic aneurysm,the area outside the cranium as well as inside must be closely examined.