Benign angiopathy of the central nervous system associated with phenytoin intoxication.

We report a patient with epilepsy who presented with acute onset of left hemiparesis associated with phenytoin intoxication due to interaction with clobazam. Magnetic resonance angiography of the head revealed stenosis of the M2 segment of the right middle cerebral artery, whereas an erythrocyte sedimentation rate and cerebrospinal fluid analysis were normal, being consistent with a diagnosis of benign angiopathy of the central nervous system. The patient exhibited an elevated plasma level of thrombin-antithrombin III complex along with a marginally increased plasma concentration of soluble E-selectin. The present case suggests that phenytoin intoxication can cause cerebral vasospasm, which may be associated with some inflammatory endothelial injury accompanied by activated intravascular coagulation.