Craspedocephalus trigonocephalus Envenomation in the United States: A Case Report

Exotic snake envenomations are increasingly encountered in the United States (US) due to the growing ownership of non-native venomous reptiles. We report the case of a 49-year-old man bitten by his own Sri Lankan green pit viper (Craspedocephalus trigonocephalus, formerly Trimeresurus trigonocephalus). The patient presented to the emergency department (ED) with rapid-onset, severe local pain and swelling extending from the bite site on his finger into the wrist. He also reported dizziness and numbness. Laboratory results were within normal limits. Poison control was contacted, and a clinical toxicologist was consulted early in the course. They accessed the Antivenom Index to identify a cross-reactive green pit viper antivenom, which was sourced from a local antivenom bank. Six vials of Hemato Polyvalent Snake Antivenin (Queen Saovabha Memorial Institute, Bangkok, Thailand) were administered intravenously (IV) five hours after envenomation. Swelling subsequently stabilized, and the patient remained hemodynamically stable with no progression of signs or symptoms. He was discharged in good condition after 26 hours of hospital observation. To our knowledge, there are currently no published case reports documenting the clinical use of Hemato Polyvalent Snake Antivenin (Queen Saovabha Memorial Institute) for this species. This case highlights the importance of early consultation with poison control and efficient coordination with institutional review boards (IRBs) and hospital pharmacies to secure life- and limb-saving treatment. Emergency clinicians should be aware of these protocols as exotic envenomations become more prevalent in the US.