Late-onset, first-ever involuntary movement after successful surgical revascularization for pediatric moyamoya disease - Report of two cases.

Background: A small number of children with Moyamoya disease develop involuntary movements as an initial presentation at the onset, which usually resolves after effective surgical revascularization. However, involuntary movements that did not occur at the onset first occur after surgery in very rare cases. In this report, we describe two pediatric cases that developed involuntary movements during the stable postoperative period after successful surgical revascularization. Case Description: A 10-year-old boy developed an ischemic stroke and successfully underwent combined bypass surgery. However, he developed chorea six months later. Another 8-year-old boy developed a transient ischemic attack and successfully underwent combined bypass surgery. However, he developed chorea three years later. In both cases, temporary use of haloperidol was quite effective in resolving the symptoms, and involuntary movements did not recur without any medication during follow-up periods of up to 10 years. Conclusion: Postoperative first-ever involuntary movement is very rare in pediatric moyamoya disease, and the underlying mechanisms are still unclear, but a temporary, reversible imbalance of excitatory and inhibitory circuits in the basal ganglia may trigger the occurrence of these rare symptoms. Careful follow-up would be mandatory.