Chronic tetanus: clinical report and histochemistry of muscle.

A patient who was partially immune to tetanus developed nonfulminant tetanus after a minor injury. Manifestations of the disease persisted for over 17 months. Electrophysiologic studies revealed an absent silent period in the masseter muscle, large-amplitude F-responses, and denervation. A muscle biopsy showed neurogenic atrophy with reinnervation. This observation supports the existence of chronic tetanus and provides morphologic evidence for a peripheral action of tetanus toxin in humans.