Bilateral carpal tunnel in childhood associated with Schwartz-Jampel syndrome.

The case of a 7-year-old girl, the only descendant of non-consanguineous parents, who presented typical features of the Schwartz-Jampel syndrome and electrophysiological evidence of bilateral carpal tunnel is reported. Conventional electromyogram (EMG) showed persistent and continuous electrical activity and high frequency discharges elicited spontaneously by movement of the needle or after voluntary activation. Electrical silence after phenytoin therapy was sometimes seen. Single fiber electromyography (SFEMG) showed that high frequency discharges had a complex configuration and multiple components. Occasionally the discharges showed a progressive decrease in amplitude. Increased jitter was also found in some potential pairs that had been isolated under voluntary contraction after phenytoin therapy. Motor and sensory conduction velocities on the median nerve were slowed bilaterally across the carpal tunnel. Bilateral carpal tunnel syndrome is an unusual condition in children and its clinical picture differs from that in adults. Carpal tunnel syndrome was not clinically suspected in the patient reported in this article and the diagnosis was confirmed by the conduction velocity study.