Cerebellar ataxia and peripheral neuropathy due to chronic bromvalerylurea poisoning

A patient with chronic bromvalerylurea poisoning showed cerebellar ataxia and peripheral neuropathy. The patient was a 42-year-old Japanese man who developed consciousness disturbance, diplopia, slurred speech, ataxia and gait disturbance after having taken bromvalerylurea for ten years. Magnetic resonance imaging revealed atrophy of the cerebellum and pontine tegmentum. An electrophysiological study revealed decreased motor nerve conduction velocity and amplitude of compound muscle action potentials of the right tibial nerve. Histological findings of the left sural nerve indicated a slightly decreased large myelinated fiber diameter, which suggested chronic axonal damage.