We present a case of pure puffer fish poisoning who developed prolonged ataxia without persistent muscle weakness. Impaired peripheral nerve conduction was suggested to be the cause of the prolonged ataxia. A 40-year-old male, a licensed puffer fish chef, tasted a piece of puffer fish liver when his stomach was empty. Approximately 20 minutes later he recognized numbness in the fingers and lips, the onset of generalized muscle weakness and paresthesia. He was admitted to our hospital for the management of progressive motor weakness one hour after ingestion. Spontaneous breathing disappeared 90 minutes after ingestion. After six hours of mechanical ventilation, spontaneous breathing resumed. Motor paralysis and paresthesia improved within 20 hours, while dizziness persisted for several days, which was not attributable to alcohol in this case. Neurological examination showed prolonged ataxia; he could not stand on one foot until the third hospital day. Serial peripheral nerve conduction velocity studies revealed decreased conduction velocities. In particular, conduction velocities of the sensory nerve were more seriously impaired and required a longer recovery time as compared to those of the motor nerve. Since tetrodotoxin does not affect the central nervous system, such prolonged ataxia in puffer fish poisoning is presumably attributable to decreased peripheral nerve conduction velocities.
