Viper snakebite envenoming — DTM&H MCQ

Correct answer: B — Immobilisation, urgent transfer and appropriate antivenom

The correct answer is B, Immobilisation, urgent transfer and appropriate antivenom. Progressive limb swelling with gum bleeding and an incoagulable 20 minute whole blood clotting test confirms venom induced consumption coagulopathy from a haemotoxic (viper) bite, which is an absolute indication for antivenom under WHO snakebite guidance. First aid should limit venom spread without causing tissue damage, so the limb is immobilised in a functional position and the patient transferred urgently to a facility holding appropriate polyvalent antivenom, since antivenom is the only treatment that neutralises circulating venom and corrects the coagulopathy. Delaying transfer or attempting local interventions increases the risk of compartment syndrome, gangrene, and fatal spontaneous haemorrhage (intracranial or gastrointestinal) from uncorrected coagulopathy. Why the other options are wrong: E. Tight arterial tourniquet until swelling stops: arterial tourniquets cause ischaemia, gangrene, and a dangerous bolus of concentrated venom on release; they are not recommended for viper bites with progressive local swelling. D. Oral antihistamine and discharge: antihistamines have no effect on venom induced coagulopathy and discharging a patient with an incoagulable clotting test risks fatal spontaneous haemorrhage. A. Pressure immobilisation as definitive therapy for swelling viper bite: pressure immobilisation bandaging is reserved for neurotoxic elapid bites with minimal local swelling; applying firm pressure over a swelling, potentially necrotic viper bite site can worsen local tissue damage and is not definitive therapy, as antivenom is still required. C. Incision and suction of the bite site: this destructive first aid measure increases bleeding risk in a coagulopathic patient, introduces infection, and does not remove clinically significant venom. Key point: an abnormal 20 minute whole blood clotting test in a snakebite victim indicates systemic haemotoxic envenoming and mandates antivenom after safe immobilisation and rapid transfer, not local wound interventions.

Reference: World Health Organization, Guidelines for the Management of Snakebites, 2nd Edition (WHO-SEARO), Section 6.6.1 (20 minute whole blood clotting test) and 6.7 (Antivenom treatment), https://cdn.who.int/media/docs/default-source/searo/india/health-topic-pdf/who-guidance-on-management-of-snakebites.pdf