rt-PA投与後，一過性に症状増悪を認めた虚血発症中大脳動脈解離の1例

Middle Cerebral Artery Dissection Treated with Intravenous Tissue Plasminogen Activator Injection: A Case Report

Ⅰ．はじめに

　2005年10月よりわが国でも発症3時間以内の超急性期脳梗塞における遺伝子組み換え組織プラスミノーゲンアクチベータ（rt-PA）が保険認可され，治療効果と合併症に関する知見が集積されつつある¹³⁾．しかし，虚血発症の脳動脈解離性病変に対するrt-PA投与の是非については一定の見解がない．われわれは，脳動脈解離による脳虚血との診断を得ることなくrt-PA静注療法を施行し，症状の緩解増悪を来した中大脳動脈解離の1例を経験したので，文献的考察を含め報告する．

　We present a case of middle cerebral artery (MCA) dissection that was treated with intravenous administration of recombinant tissue plasminogen activator (rt-PA). A 72-year-old woman suddenly developed dysarthria and left motor weakness without headache. On arrival at the hospital,her NIH stroke scale (NIHSS) score was 13. Magnetic resonance imaging (MRI) revealed severe stenosis of the right proximal MCA segment; this appeared to be the cause of atherothrombosis. After the MRI study,her NIHSS score improved to 5,but the evidence of MCA stenosis indicated the need for thrombolytic treatment. We injected rt-PA 102 min after the symptom onset; however,her NIHSS score fluctuated thereafter; at worst,it was 13 at 78 min after the initiation of rt-PA treatment. Eventually,her neurological status improved and after 12 hours,her NIHSS score improved to 1 but the MRI showed cerebral infarction restricted in the right putamen. Since persistent irregularity of the right MCA was shown by follow-up magnetic resonance angiography (MRA),digital subtraction angiography was performed on the 14th day after admission. Double lumen of the right MCA was detected,which was a definite proof of artery dissection. Here,we discuss the difficulties encountered in the diagnosis and treatment for MCA dissection.