Peripheral neuropathy in multiple system atrophy with autonomic failure.

Two patients with multiple system atrophy, autonomic failure, and peripheral neuropathy are reported. EMG conduction study in both muscle and sural nerve histology in one patient documented the involvement of the neuromuscular system. Morphologic study of the biopsied nerve showed marked reduction of large myelinated fibers, whereas the unmyelinated axons were totally spared. The latter finding provides evidence that the syspathetic nervous system contributes few, if any, axons to the total population of unmyelinated fibers in the human sural nerve. Peripheral nerve damage may be common in the Shy-Drager syndrome.