短期間に両側内頚動脈瘤破裂を繰り返した結節性多発動脈炎の1例

Repeated Rupture of Bilateral Internal Carotid Artery Aneurysms in a Short Period in Association with Polyarteritis Nodosa:A Case Report

Ⅰ．はじめに

　結節性多発動脈炎（polyarteritis nodosa：PAN）は中・小動脈に壊死性血管炎を生じ，多臓器に塞栓，血栓，動脈瘤形成を引き起こす疾患である．当初は顕微鏡的多発血管炎（microscopic polyangitis：MPA）も同一の疾患群としてとらえられていたが，現在ではPANはMPAとは独立した疾患であることが確立している⁸⁾．MPAに比較するとPANは稀な疾患であり，本邦では100万人あたり11.7人の有病率と推計されている¹¹⁾．PANでは血管壁の脆弱性による微小動脈瘤や血管炎による狭窄の合併が知られており²⁾，腎動脈では66.2%，腸間膜動脈では57.7%に微小動脈瘤あるいは狭窄が認められたと報告されている¹³⁾．しかしながら，脳動脈瘤の報告は散見される程度で，極めて稀である^5,12,21,24)．

　今回われわれは，たこつぼ型心筋症（takotsubo cardiomyopathy：TCM）を合併し短期間に両側内頚動脈瘤破裂を繰り返したPANの症例を経験したので，文献的考察を加え報告する．

　Cerebral involvement is rare in polyarteritis nodosa（PAN）;furthermore, secondary intracranial hemorrhage due to cerebral aneurysm is extremely rare. We describe an unusual case of repeated subarachnoid hemorrhage（SAH）in a 64-year-old woman with a history of PAN. Initially, she developed severe headache（probable first SAH, day 0), and presented at our hospital with second severe headache with disturbed consciousness on day 6. Computed tomography（CT）revealed that SAH was mainly distributed in the right basal cistern and sylvian fissure（second SAH). Three aneurysms were detected using CT angiography on the bilateral internal carotid arteries. An intentionally delayed surgery was planned because of the high risk period of cerebral vasospasm and takotsubo cardiomyopathy. On day 15, she complained of headache and had a convulsion. CT revealed a third SAH in the left sylvian fissure;cerebral angiography revealed enlargement of the left internal carotid-posterior communicating artery（IC-PC）aneurysm. Coil embolization of the aneurysm was performed on day 16, and she was treated using prednisolone（20mg/day）for PAN. However, on day 20, the patient became comatose, and CT revealed a fourth SAH in the right sylvian fissure. Cerebral angiography revealed enlargement of the right IC-PC aneurysm. Clipping of the aneurysm was successfully performed in spite of ventricular dysfunction, and the dose of prednisolone was increased to 40mg/day. After treatment, the ventricular dysfunction gradually resolved. Cerebral aneurysms with PAN are candidates for intervention because of their strong tendency to rupture. In our case, takotsubo cardiomyopathy might have been associated with impairment of the coronary microcirculation due to PAN. We suggest that aggressive immunosuppressive treatment for PAN and curative treatments for cerebral aneurysms should be considered with careful radiological examination and follow-up monitoring.