Tetrodotoxin toxicity: an increasing threat

A man aged in his sixties presented to the emergency department with vomiting, dizziness and generalised weakness preceded by perioral and peripheral paraesthesias for several hours. He did not speak English and was visiting from overseas. Examination revealed multidirectional nystagmus, subtle bilateral ptosis, marked bilateral upper limb dysmetria and heel-shin ataxia, with mild proximal limb weakness. Brain imaging was unremarkable. Further history revealed the man had gone fishing and eaten a fish he had caught earlier that day. He was subsequently diagnosed with tetrodotoxin toxicity from pufferfish ingestion. He was managed supportively and made a complete recovery. Tetrodotoxicity has been hitherto considered rare outside of Southeast Asia, but rising water temperatures and human interventions have facilitated the migration of marine species containing tetrodotoxin to a wider geographical range.