Neuropathy in tetanus

Thirty-four cases of severe tetanus were studied. On clinical examination weakness and sensory loss compatible with peripheral neuropathy was found in 27. The pattern was usually asymmetrical, the commonest nerves affected being ulnar, median and lateral popliteal, although occasionally circumflex, musculocutaneous, femoral and facial nerves were also involved. Electrophysiological studies showed spontaneous activity resembling denervation potentials, diphasic and positive sharp waves. In some muscles there was also activity resembling spontaneous firing of motor units. Motor and sensory conduction velocities in the affected nerves were moderately reduced and the amplitude of sensory potentials was also reduced. No conduction was found in 11 nerves in 8 patients on initial studies, but 4 out of 7 nerves that could be studied showed rapid recovery. Although most of the nerves in the rest of the patients showed clinical recovery, conduction velocities showed improvement most often when examined about 10 weeks after the onset of trismus. The clinical and electrophysiological evidence suggests the involvement of peripheral nerves in severe tetanus. Serum neuritis, hypersensitivity reaction to tetanus toxoid or drug-induced neuropathy have been ruled out.