Diagnosis & Treatment — First aid / lay people
see also Warrell (2004) Snakebites in Central and South America: Epidemiology, Clinical Features, and Clinical Management. In: Venom Poisoning by North American Reptiles. In: J. A. Campbell and W. W. Lamar: The Venomous Reptiles of the Northern Hemisphere. Comstock; Ithaca, London S. 709-761
General problems
- Fear,
- collapse, loss of consciousness.
- Calm the patient.
- Place the patient in a stable lateral position, or possibly the Trendelenburg position (shock position).
Anxiety (fear of death) plays an important role following accidents with venomous animals and has an additional negative influence on the clinical course after an accident.
Loss of consciousness after an accident with a venomous animal can have many causes. It is important to place the patient in a stable lateral position to avoid aspiration. If peripheral circulatory failure is present, the shock position may improve the patient's condition. If resuscitation is necessary, it is only in exceptional cases that lay people will be sufficiently well trained to be able to intervene.
How can absorption and circulation of the venom be delayed?
Elapids (Micrurus sp.) and
Crotalids (C. durissus terrificus and other C. durissus ssp. that cause symptoms of paralysis):
- Compression-immobilisation method or comparable methods and splinting of the bitten extremity.
- Avoid pressure points when applying the splint (padding). Transport the patient.
Crotalids (apart from C. durissus terrificus and other C. durissus ssp. that cause symptoms of paralysis), colubrids:
- Immobilisation of the bitten extremity using a splint (piece of wood or something similar).
- Avoid pressure points when applying the splint (padding). Transport the patient.
The risks of the compression-immobilisation method limit its use to elapid bites (Micrurus sp.), which are uncommon, and to bites from C. durissus terrificus and other C. durissus ssp. that cause symptoms of paralysis. In both cases identification of the snakes is simple even for lay people. Micrurus sp. are distinctive due to their typical markings and colouring, and C. durissus because of the rattle. Following bites from C. durissus in the southern regions of the distribution area of this species, local swelling is minor or absent, and following Micrurus sp. bites it is almost always absent.
Average time between the bite and death
Elapids (Micrurus sp.): 4–6 h (Rosenfeld 1971).
Crotalids (C. durissus): 1–3 days (in patients with severe envenoming); 1 week (as a consequence of renal insufficiency) (Rosenfeld 1971).
Crotalids, apart from C. durissus (Bothrops sp. and Lachesis muta): several days (Rosenfeld 1971). These data do not take into account early fatalities due to autopharmacological effects of the venom.