Trauma and amyotrophic lateral sclerosis.

Abstract

To the Editor. —Despite long-standing suspicions1-4and scant epidemiologic evidence,5-7trauma is far too common to implicate as a direct cause of amyotrophic lateral sclerosis (ALS). However, the occurrence of ALS in a young man nine months following radial nerve injury suggested a possible mechanism for their association. Report of a Case. —A 33-year-old man slipped while walking on a moving railroad car. He was able to hang on to a bar with his left hand. His body was suddenly twisted, and he experienced an electricshock sensation radiating down his left arm. Immediately after getting off the train, he could not extend his left wrist. On neurologic evaluation four weeks later, left wrist extensors were grade 4 (Medical Research Council Scale), left finger extensors were grade 4—, and left deltoid and triceps were grade 5. Electromyographic studies indicated left radial conduction block and axonal injury. The remaining results