Snake Bite Classification

Very broadly, snakebite envenoming based on their venom components can be classified in the following clinical patterns of envenoming:

1. Cytotoxic envenoming is characterized by painful and progressive swelling with blood-stained tissue fluid leaking from the bite wound, hypovolaemic shock, blistering and bruising. The victim will complain of severe pain at the bite site and throughout the affected limb, and painful and tender enlargement of lymph glands draining the bite site. Species involved with this type of bite include spitting cobras, carpet viper, puff adders, Gaboon and rhinoceros vipers.
2. Haemorrhagic envenoming is characterized by bleeding from the gums, gastro-intestinal and genito-urinary tracts, and bleeding from recent and partly healed wounds. Species involved with this type of bite include carpet viper, Gaboon and rhinoceros vipers, boomslang and vine snakes.
3. Neurotoxic envenoming is characterized by moderate or absent local swelling, progressive descending paralysis starting with drooping eyelids and paralysis of eye movements. There may be painful and tender enlargement of lymph glands draining the bite site. The patient may vomit, the saliva may become profuse and stringy and eventually there may be difficulties with swallowing and breathing. Species involved with this type of bite include black and green mambas, non-spitting cobras and Berg adders.
4. Myotoxic envenoming is characterized by negligible local swelling, increasing generalized muscle pain and tenderness associated with features neurotoxic envenoming and progressive descending paralysis culminating in paralysis of breathing. The species involved with this type of bite include yellow-bellied sea snakes.

Mixed type of envenoming may occur. Mixed cytotoxic and neurotoxic bites in the case of rinkhals but not with other spitting cobras. Mixed haemorrhagic and cytotoxic bites from carpet vipers, North African desert vipers and puff adders.