Isolated triceps weakness in exercise-induced radial neuropathy.

OBJECTIVE

We report a case of isolated triceps weakness resulting from radial neuropathy.

PATIENT: A middle-aged healthy man, a keen athlete, developed acute weakness of the triceps brachii muscle due to radial neuropathy. No other radial nerve innervated muscles were involved. Triceps function completely recovered in six weeks clinically and electrophysiologically suggesting focal conduction block secondary to demyelination.

DISCUSSION: Acute radial neuropathy after strenuous arm exercise resulting from a compression lesion with acute conduction block, has been previously described. However, all reported cases involved severe weakness of radial nerve innervated distal muscles with wrist drop, while isolated weakness of the triceps brachii muscle in radial neuropathy has never been previously described.

CONCLUSIONS

We suggest that selective weakness in the triceps could be the sole manifestation of an exercise-related radial neuropathy. This particular type of radial neuropathy could be a variant of neuralgic amyotrophy.