Emergency Flowchart

Signs and symptoms¹	Supportive emergency medical treatment	Identification of the culprit	Antivenom

	Possible culprit²


Nausea, vomiting, abdominal pain, diarrhoea, urticaria, angio-oedema, bronchospasm, arterial hypotension (autopharmacological effects of the venom including anaphylaxis)	Treatment of anaphylactic/anaphylactoid reactions	Identification strategies 1. Morphological identification key (if snake is available for identification) 2. Narrowing down the cause with the aid of indirect criteria (if the snake is unavailable or could not be unequivocally identified) Which snake species are present in the country where the snake bite took place? Under what circumstances did the snake bite occur, and how did the snake behave? Syndromic approach: How does the clinical picture of snakebite envenoming develop? Comparative observations of the various species responsible in the region. Follow also links to species- and family-specific 'clinical entries' in the column `possible culprit' of this flowchart.	WHO Snakebite Information and Data Platform Check for nationally / regionally available antivenoms (assure safety and effectiveness). Antivenom indications and antivenom therapy: go to 'clinical management'. Check for updates in case of an accident.

	Bothrops sp.

Generalised oedema → hypovolaemia → hypovolaemic shock (autopharmacological effect of the venom: increased capillary permeability)	Treatment of hypovolaemia/hypovolaemic shock



Extensive local swelling possibly involving the trunk → hypovolaemia → hypovolaemic shock (local effect of the venom: regionally increased capillary permeability)	Treatment of hypovolaemia/hypovolaemic shock

	Bothrops sp. Lachesis sp.

Systemic bleeding → hypovolaemia → haemorrhagic shock (haemostatic effects of the venom) Intracranial bleeding → focal neurological deficits, coma, meningismus (haemostatic effects of the venom)	Treatment of blood loss Treatment of intracranial bleeding

	Bothrops sp.^3,4 (Crotalus durissus ssp.) Lachesis sp.

Cranial nerve deficits, paralysis of the skeletal musculature including the respiratory musculature → respiratory insufficiency, respiratory failure (neurological effects of the venom)	Treatment of respiratory insufficiency/respiratory failure acetylcholinesterase inhibitors, endotracheal intubation and artificial respiration

	Micrurus sp. Crotalus durissus ssp.

Sweating, repeated bilious vomiting, severe abdominal colic, profuse diarrhoea, hypotension, sinus bradycardia, and shock (autonomic syndrome)	Treatment of hypotension/shock, bradycardia, vomiting.

	Lachesis sp.⁵

Myalgia, pain on active/passive movement and upon pressure, ECG changes (hyperkalaemia), signs of paralysis, urine colour (differential diagnosis haemoglobinuria), renal failure (musculareffect of the venom: rhabdomyolysis)	Treatment of hyperkalaemia, prevention and treatment of acute renal failure, treatment of respiratory insufficiency/respiratory failure

	Crotalus durissus ssp.

Myocardial symptoms, cardiac dysrhythmias, ischaemia (ECG), cardiac insufficiency, heart failure (usually secondary, rarely primary cardiac effects of the venom)	Treatment of the cardiac disturbance



Acute renal failure (usually secondary, rarely primary renal effects of the venom)	Treatment of acute renal failure

	Bothrops sp.⁶ Crotalus durissus ssp.⁷

This section contains genera and species for which clinical data is either sparse or entirely missing. In this case, the link will lead you to the biological file. Under 'Risk', you will find what is known about the potential harm to humans which are well described for adjacent regions but not for the region you are currently looking at. The link will take you to the biological file and from there to the clinical file. When using the clinical information, however, you must consider that it is not from your region and therefore may not be applicable to your situation.	Follow ABCDE approach

	Colubridae Leptomicrurus sp. Bothriechis sp. Bothriopsis sp. Bothrocophias sp. Porthidium sp.

1	See also the Clinical flowchart as a guide to the dynamics of envenoming.
2	Taxonomic name without parentheses/(in parentheses)/((in double parentheses)): these signs and symptoms are regularly/(rarely)/((questionably)) observed following bites by these species.
3	Bothrops atrox (Duarte et al. 2025, Warrell 2009), Bothrops erythromelas (Mota et al. 2020), Bothrops jararaca (Amaral et al. 1985, Bucaretchi et al. 2019, Malaque et al. 2019), Bothrops lanceolatus (Malbranque et al. 2008) envenoming can, addtionally, cause thrombotic micro-angiopathy (TMA).
4	Bothrops lanceolatus “In situ arterial thrombosis (cerebral, pulmonary, coronary, etc.) is an important additional feature of envenoming by the ‘fer-de-lance’ (B. lanceolatus) of Martinique (Warrell 2023).
5	Lachesis sp. “Bushmaster (Lachesis sp.) envenoming causes a distinctive autonomic syndrome of sweating, repeated bilious vomiting, severe abdominal colic, profuse diarrhoea, hypotension, sinus bradycardia, and shock that can develop as early as 15 min after the bite.” (Warrell and Williams 2023; cit. Bolaños et al. 1982, Jorge et al. 1997).
6	AKI results from a combination of factors, possibly including direct action of the venom (Malaque and Gutiérrez 2017; Pinho et al. 2008, Sitprija 2006; Warrell 2004, 2023).
7	After Crotalus snakebite in South America, the most common complication is AKI due to rhabdomyolysis (Azevedo-Marques et al. 1985, 1987; Malaque and Gutiérrez 2017; Pinoh et al. 2005, 2008; Silveira and Nishioka 1992; Warrell 2004, 2023).