Acute polyneuropathy with severe generalized rigidity in a child aged 16 months. Preliminary report.

A case of acute severe generalized muscle rigidity in a 16-month-old child is described. The arm flexors and leg extensors were the most severely involved, with all stretch reflexes absent. Motor conduction velocities on the arms and legs were very slow and nerve potentials were not elicited. The rigidity and electromyographically recorded spontaneous activity almost disappeared on carbamazepine treatment, with nerve conduction velocities remaining unchanged.