Moyamoya-induced paroxysmal dyskinesia.

Moyamoya disease (MMD) is an uncommon intracranial vasculopathy that typically presents with ischemic or hemorrhagic stroke. Persistent choreoathetosis has been identified as a rare early manifestation of MMD. We present 2 patients with paroxysmal dyskinesia as the initial symptom of MMD, one resembling paroxysmal kinesigenic dyskinesia (PKD) and the other paroxysmal non-kinesigenic dyskinesia (PNKD). We also review the cases of moyamoya-induced chorea reported previously, none of which resembled PKD or PNKD. We hypothesize that both hormonal and ischemic factors may be implicated in the pathogenesis of these abnormal involuntary movements. These cases suggest that MMD should be included in the differential diagnosis of PKD and PNKD.