[Middle cerebral artery dissection treated with intravenous tissue plasminogen activator injection: a case report].

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.