Table 1

Mechanism, signs and symptoms of predominant snakebite envenoming systemic effects

MechanismTypical symptoms and signsTypical snakes associated
Neurotoxic effects
Blockade at presynaptic and/or postsynaptic sites of neuromuscular junctionDescending paralysis, ptosis, ophthalmoplegia, salivation, dysphagia can progress to generalised flaccid paralysis and respiratory arrestElapids (mambas, cobras, kraits, some rattlesnakes)
Haemotoxic effects
Degradation of capillary basement membraneLocal and systemic bleedingViperids (saw-scaled vipers, puff adders, Russell’s viper, rattlesnakes, lancehead vipers)
Consumption of blood clotting factors, thrombocytopeniaVenom-induced consumption coagulopathy Systemic bleeding including epistaxis, gingival, gastrointestinal, intracranial bleeding42 Viperids, some colubrids (eg, boomslangs and vine snakes)
Vasoactive substances in venoms or release of endogenous vasoactive substancesIncreased in vascular permeabilityViperids, atractaspids
Renal effects
Renal impairment from direct nephrotoxicity, shock, thrombotic microangiopathy, hypovolaemia, rhabdomyolysisElectrolyte disturbances, acute kidney injuryViperids (Russell’s viper, South American rattlesnake) Elapids (New Guinea small-eyed snakes, Australian tigers snakes, black snakes and taipans)