Motor and sensory neuropathy secondary to excessive pyridoxine ingestion

This report documents a case of mixed motor and sensory neuropathy that resulted from ingestion of excessive amounts of pyridoxine. An 81-year-old woman was admitted to the hospital because of difficulty in walking and frequent falls. History revealed that she had been taking large doses of pyridoxine daily for several months as treatment for carpal tunnel syndrome. Diagnostic work-up failed to suggest a cause for her symptoms. Nerve conduction studies revealed slowing of motor conduction velocities, prolonged F wave latencies, and prolonged sensory latencies in both lower extremities. We believe the patient's complaints and the results of nerve conduction studies were secondary to pyridoxine neurotoxicity. Since the bases for this neurotoxicity are unknown, we suggest that treatment of carpal tunnel syndrome with oral pyridoxine be carefully monitored and that dosage limits not be exceeded.