Hemiballismus revealing multiple sclerosis in an infant.

The authors report a case of a 15-month-old infant who presented a left hemiballismus associated with left Marcus-Gunn pupil, and retrobulbar optic neuritis, which disappeared spontaneously in 7 days. Six weeks later, the infant experienced a mild paraparesis with a palsy of the left sixth cranial nerve, which disappeared following steroid therapy. Evoked visual potentials elicited abnormal latencies; cerebrospinal fluid (CSF) showed a rise in white cells and oligoclonal bands. According to the usual classification, this case corresponds to definite multiple sclerosis. The fact that hemiballismus was the initial clinical feature in an infant makes this observation very interesting. In the literature, eight cases of hemiballismus in patients with multiple sclerosis are reported; however, only two cases of multiple sclerosis in infancy have been published, making our case report of particular interest.