Clinic: Colubrids

Examine for venom effects

Autopharmacological effects

• Nausea, vomiting
• Sweating
• Urticaria, angiooedema
• Arterial hypotension / hypovolaemic shock (transient, recurrent; immediate; delayed (CLS))
• Diarrhoea
• Bronchospasm 

Local Effects

• Pain
• Tender local (spreading) swelling
• Blistering
• Lymphangiopathy and lymphadenopathy
• Necrotic skin

Haematological effects 

• Clotting disturbances:
  • Bleeding from the fang marks and from injuries, in particular ones that are not located in the region in which venom application occurred.
  • Bleeding into the skin (ecchymosis, petechiae)
  • Gingival bleeding, bleeding from the nose, conjunctiva, haematemeis, bleeding per rectum, including melaena, haematuria, haemoptysis.
  • Oliguria, anuria (VICC / AKI)
• Bleeding and/or haemolytic anaemia:
  • Arterial hypotension (haemorrhagic shock)
  • Acute abdomen (intra-abdominal bleeding!)
  • Loin pain/renal bed sensitive to percussion (ischaemia, renal haemorrhage!)
  • Local neurological signs, meningism, coma (intracranial bleeding!)
  • Pale sclera (bleeding, haemolysis!)
  • Oliguria, anuria (arterial hypotension / AKI!)

Neurological effects

• Descending flaccid paralysis (rarely progresses to involve bulbar and respiratory muscles):
  • Ptosis (not to be mixed up with tiredness / drowsiness; test: lid retraction with upward gaze).
  • Double vision (external ophthalmoplegia)
  • Difficulties to swallow (dysphagia) (bulbar paralysis) > inhalation of vomitus!
  • Difficulties to lift the head when lying on the back (‘broken neck syndrome’)
  • Cyanosis, shallow breathing, respiratory arrest (respiratory paralysis); respiratory arrest may be precipitated by obstruction of the upper airway by the paralysed tongue or inhaled vomitus. 
  • Weakness or loss of voluntary movement; movements of digits may still be possible, allowing the patient to communicate.
  • Loss of consciousness and generalized convulsions caused by hypoxaemia in patients who have respiratory paralysis.  

Species-specific envenoming pattern

The assessment of the envenoming pattern is based on the data from publication in which the identification of the snakes is clearly specified and in accordance with accepted criteria.

^ABoiga irregularis

Local effects 

• Local swelling with skin discolouration and blistering 3/4, local swelling without skin discolouration or blistering 1/4, necroses 0/4 (Fritts et al. 1990). 

Neurological effects

• Ptosis 2/4, muscle weakness in the extremities 1/4, spastic movements of the extremities 1/4, respiratory problems 2/4, whereby one child suffered respiratory arrest (in one child, the treating doctor did not exclude an anaphylactoid cause of the serious course of the envenoming with respiratory arrest) (Fritts et al. 1990). I

^BDyspholidus typus.

Autopharmacological effects

• Nausea, vomiting, diarrhoea.

Local effect

• Limited local effect.

Hematological effects

Bleeding
Systemic bleeding 

• Gingival bleeding, epistaxis, haemoptysis, haematuria, bleeding per rectum, melaena, extensive subcutaneous and intracranial bleeding (within hours).

• Acute kidney failure (secondary to DIC)
• Haemoglobin
  Minimum 9.4 g/100 ml (initial value 12.5 g/100 ml) (Akimoto et al. 1991); 8.5 g/100 ml (initial value 13.0 g/100 ml) (Mandell et al. 1980).

Coagulopathy
Type of haemostatic defect

• DIC due to activation of factor X and direct conversion of prothrombin to thrombin (Mackay et al. 1969). Thrombopaenia in the context of DIC. Haemorrhagic effect (Christensen, pers. commun. cited in Nicolson et al. 1974).
• Haemoglobin
  Minimum 7.4 g/100 ml (initial value 18.1 g/100 ml) (Lakier and Fritz 1969), minimum 10.8 g/ml (initial value 13 g/ml) (Nicolson et al. 1974).
• Haemostatic parameters
  CT: increased.
  PT, aPTT: increased.
  Fibrinogen: 0.35 g/l (Geddes and Thomas 1985); 0.1 g/l (Lakier and Fritz 1969).
  TT: increased.
  FSP: ≥1,280 g/ml ≤2,660 g/l (Geddes and Thomas 1985).
  Platelets: minimum 8,000/mm³ (Nicolson et al. 1974); minimum 10,000/mm³ (Lakier and Fritz 1969).

Case fatality

• Intracranial bleeding (Pope 1958).

^CRhabdophis subminiatus, Rhabdophis tigrinus

Autopharmacological effects

• Nausea, vomiting (aetiology?).

Local effect

• Local pain can occur, but is not always reported.

• Local swelling is generally mild and only directly around the site of the bite, but it can extend to adjacent parts of the affected extremity, ecchymosis.

Hematological effects

Bleeding
Systemic bleeding

• Bleeding from wounds, gingival bleeding, epistaxis, haematuria, gastrointestinal bleeding, melaena, intracranial bleeding (onset of bleeding within a few hours to 10 h after the bite).
• Acute kidney failure (secondary to DIC).

Coagulopathy

Type of haemostatic defect

• DIC due to direct activation of prothrombin (Nahas et al. 1976, Sakai et al. 1983, 1990). Thrombopaenia in the context of the DIC. Slight haemorrhagic effect (Akimoto et al. 1991). Reactive (secondary) hyperfibrinolysis.

• • • Acute kidney failure (secondary to DIC).
    • Haemoglobin
      Minimum 9.4 g/100 ml (initial value 12.5 g/100 ml) (Akimoto et al. 1991); 8.5 g/100 ml (initial value 13.0 g/100 ml) (Mandell et al. 1980).
    • Haemostatic parameters
      CT: increased.
      PT, aPTT: increased.

      Fibrinogen: decreased to undetectable; Rhabdophis subminiatus: Minimum no longer detectable. Fibrinogen became detectable again from the 7th day after the bite (Cable et al. 1984).
      FSP: elavated to very high
      Platelets: decreased. Rhabdophis subminiatus: Minimum 79,000/mm³, first spontaneous platelet increase on the 7th day after the bite (Cable et al. 1984). 

^DThelotornis kirtlandii, Thelotornis capensis

Local effect

• Local swelling which may extend to adjacent areas of the affected extremity.

Hematological effects

Bleeding
Systemic bleeding 

• Bleeding from superficial wounds, even those which had already healed; gingival bleeding, epistaxis, haematemesis, bleeding per rectum, haematuria, intracranial bleeding.
• Anaemia
• Acute kidney failure (secondary to DIC).

Coagulopathy
Type of haemostatic defect

• Probably similar to Dispholidus typus envenoming (Minton 1990b).
  Haemostatic parameters
  CT: increased (Saddler and Paul 1988).
  PT, aPTT: increased (Saddler and Paul 1988).
  Fibrinogen: afibrinogenaemia (Mebs et al. 1978).

Case fatality rate

• Intracranial bleeding (and bleeding into the pericardium, pleura, retroperitoneum, stomach and both kidneys) (FitzSimons and Smith 1958).
• Intracranial bleeding (and bleeding from virtually all mucous membranes) (Mebs et al. 1978). 

Species-specific publications: see ‘References’ at the end of the file. 

Clinical management

First Aid

If a tourniquet has been applied, it should not be removed until

• systemic envenoming has been excluded: absence of non-specific systemic symptoms and normal results of laboratory investigations (Ireland et al. 2010, Isbister and Berling 2025)
  or

• after compeltion of antivenom administration for patients with systemic envenoming (Isbister et al. 2025).

• adverse outcomes have been observed in patinets with tight pressure bandages left in place for many hours (Little 2023).
• all patients must be observed after removal of the bandage.

Local treatment

Pain control
Tetanus prophylaxis
Standard wound care
Necroses: debridement; split-thickness skin grafting
Systemic antibiotics: standard indications
WHO (2010a, 2010b, 2016) 

Systemic supportive treatment

A general understanding of emergency medicine is required, or can be found in emergency medicine guidelines, e.g. ABCDE approach, WHO-ICRC Basic Emergency Care.

Follow SAMPLE & ABCDE ApproAch

• Comprehensive ABCDE approach

• ICRC Basic Emergency Care: approach to the acutely ill and injured (SAMPLE  and ABCDE approach: first module)

Obey colubridae - specific features

see

• 'Species-specific envenoming pattern above'.

and

• Guidelines for the Prevention and Clinical Management of snakebite in Africa
• National Snakebite Management Guidelines (2021) WHO Eswatini, Eswatini Antivenom Foundation
• Guidelines for the Management of Snakebites, WHO Regional Office SE Asia

Key issues:

Respiratory failure 

Boiga irregularis

Systemic bleeding

Dyspholidus typus, Rhabdophis subminiatus, Rhabdophis tigrinus, Theleotornis kirtlandii, Thelotornis capensis

Acute kidney injury (AKI) 

Dyspholidus typus, Rhabdophis sp., Theleotornis sp.

Secondary to renal ischaemia secondary to shock, disseminated intravascular coagulation.

Specific treatment (antivenoms)

• WHO Snakebite Information and Data Platform
• Guidelines for the Prevention and Clinical Management of snakebite in Africa
• National Snakebite Management Guidelines (2021) WHO Eswatini, Eswatini Antivenom Foundation
• World Health Organization(2023). Target product profiles for animal plasma-derived antivenoms: antivenoms for treatment of snakebite envenoming in sub-Saharan Africa
• Guidelines for the Management of Snakebites, WHO Regional Office SE Asia

References

See also References in section Species-specific evidence'

• Warrell DA. Venomous and poisonous animals.In: Farrar J, Garcia PJ, Hotez T, Junghanss T, Kang G, Laloo D (eds.). Manson’s tropical diseases. 24th ed. Elsevier; 2023.
• Warrell DA, Williams DJ. Clinical aspects of snakebite envenoming and its treatment in low-resource settings. Lancet. 2023 Apr 22;401(10385):1382-1398. PMID: 36931290. https://doi.org/10.1016/s0140-6736(23)00002-8
• WHO (2016) Guidelines for the management of snakebites. 2^nd edition. https://www.who.int/publications/i/item/9789290225300
• WHO (2010a) Guidelines for the prevention and clinical management of snakebite in Africa. https://www.who.int/publications/i/item/9789290231684
• WHO (2010b) Wound and lymphoedema management. WHO/HTM/NTD/GBUI/20101 I. 2010. https://www.who.int/publications/i/item/9789241599139
• WHO-ICRC Basic Emergency Care: approach to the acutely ill and injured (2018)  https://www.who.int/publications-detail-redirect/basic-emergency-care-approach-to-the-acutely-ill-and-injured
• WHO ABCDE Approach  https://cdn.who.int/media/docs/default-source/integrated-health-services-(ihs)/csy/bec-quick-cards/becp-edu29-pdf-en-finl.pdf?sfvrsn=2532d61b_2
• WHO Snakebite Information and Data Platform  https://www.who.int/teams/control-of-neglected-tropical-diseases/snakebite-envenoming/snakebite-information-and-data-platform

 Species-specific evidence

Boiga irregularis

Guam

• Fritts et al. (1990)4 bites in children; identification: geographical exclusion.

Dyspholidus typus

• Pope (1958), Spies et al. (1962), Lakier and Fritz (1969), Mackay et al. (1969), Matell et al. (1973), Nicolson et al. (1974), Visser and Chapman (1978), Gerber and Adendorf (1980), Geddes and Thomas (1985), Broadley (1960)
• Minton (1990b) and case reports.

Rhabdophis sp.

Rhabdophis subminiatus

• Cable et al. (1984), Mather et al. (1978)

Rhabdophis tigrinus

• Mittleman and Goris (1974, 1978), Kono and Sawai (1975), Minton and Mebs (1978), Mandell et al. (1980), Mori et al. (1983), Akimoto et al. (1991), Nomura et al. (1989), Ogawa and Sawai (1986), Matsuda et al. (1990)
• Minton (1990b) and case reports

Theleotornis sp. 

Thelotornis kirtlandii

• FitzSimons and Smith (1958), Beiran and Currie (1967), Mebs et al. (1978), Visser and Chapman (1978), Blaylock (1960), Broadley (1957)

Thelotornis capensis

• Atkinson et al. (1980), Saddler and Paul (1988)

References

• Akimoto, R., Y. Watanabe, A. Sakai, Y. Kawamura, Y. Sawai (1991) A case of defibrination syndrome due to Japanese colubrid snake, yamakagashi (Rhabdophis t. tigrinus) bite, treated with antivenom. Snake 23: 36-39
• Atkinson, P. M., B. A. Bradlow, J. A. M. White, H. B. Greig, M. C. Gaillard (1980) Clinical features of twig snake Thelotornis capensis envenomation. S. Afr. med. J. 58: 1007-1011
• Beiran, C., G. Currie (1967) Snake bite due to Thelotornis kirtlandii. Centr. Afr. med. J. 13: 137-139
• Blaylock, R. S. M. (1960) A bite from a vine snake in Bulawayo. J. Herp. Ass. Rhod. 12: 8-9
• Broadley, D. G. (1957) Fatalities from bites of Dispholidus and Thelotornis and a personal case history. J. Herp. Ass. Rhod. 1: 5
• Broadley, D. G. (1960) Case history of a boomslang (Dispholidus typus) bite. J. Herp. Ass. Rhod. 11: 7-8
• Cable, D., W. McGehee, W. Wingert, F. E. Russell (1984) Prolonged defibrination after a bite from a “nonvenomous” snake. J. Amer. med. Ass. 251: 925-926
• FitzSimons, D. C., H. M. Smith (1958) Another rear-fanged South African snake lethal to humans. Herpetologica 14: 198-202
• Fritts, T. H., M. J. McCoid, R. L. Haddock (1990) Risk to infants on Guam from snake bite of the brown tree snake (Boiga irregularis). Amer. J. Trop. Med. Hyg. 42: 607-611
• Geddes, J., J. E. P. Thomas (1985) Bommslang bite-a case report. Cent. Afr. J. Med. 31: 109-112
• Gerber, J. D. W., H. P. F. Adendorf (1980) Boomslang byt’n Gevalbespreking. S. Afr. med. J. 57: 710-711
• Kono, H., Y. Sawai (1975) Systemic poisoning from the bite of Rhabdophis tigrinus. Snake 7: 38-39
• Lakier, J. B., V. U. Fritz (1969) Consumptive coagulopathy caused by a boomslang bite. S. Afr. med. J.: 1052-1055
• Mackay, N., J. C. Ferguson, A. Bagshawe, A. T. T. Forrester, C. O. McNicol (1969) The venom of the boomslang (Dispholidus typus) in vivo and in vitro studies. Thrombosis 21: 234-244
• Mandell, F., J. Bates, M. B. Mittleman, J. W. Loy (1980) Major coagulopathy and “nonpoisonous” snake bites. Pediatrics 65: 314-317
• Matell, G., D. Nyman, B. Werner, S. Wilhelmsson (1973) Consumptive coagulopathy caused by a boomslang bite. Tromb. Res. 3: 173-182
• Mather, H. M., S. Moyne, T. M. McMonagle (1978) Severe envenomation from “harmless” pet snake. Brit. med. J. 1: 1324-1326
• Matsuda, R., S. Ilzuka, M. Narai (1990) A case of defibrination syndrome due to snake (Rhabdophis tigrinus) bite. Tottori Med. J. 18: 182-187
• Mebs, D., I. Scharrer, W. Stille, H. Hauk (1978) A fatal case of snake bite due to Thelotornis kirtlandii. In Rosenberg, P.: Toxins: Animal, Plant and Microbial (Proceedings of the fifth international symposium): 477-479
• Minton, S. A. (1990b) Venomous bites by nonvenomous snakes: An annotated bibliography of colubrid envenomation. J. Wilderness Med. 1: 119-127
• Minton, S. A., D. Mebs (1978) Vier Bißfälle durch Colubriden. Salamandra 14: 41-44
• Mittleman, M. B., R. C. Goris (1974) Envenomation from the bite of the Japanese colubrid (Rhabdophis tigrinus). Herpetologica 30: 113-119
• Mittleman, M. B., R. C. Goris (1978) Death caused by the bite of the Japanese colubrid snake Rhabdophis tigrinus (Boie) (reptilia, serpentes, colubridae). J. Herpetol. 12: 109-111
• Mori, J., M. Yamakawa, Y. A. Kawamura (1983) A case of severe defibrination syndrome due to snake (Rhabdophis tigrinus) bite. Rinsha Ketsueki 24: 256-262
• Nicolson, I. C., P. A. Ashby, N. D. Johnson, J. Versey, L. Slater (1974) Boomslang bite with haemorrhage and activation of complement by the alternate pathway. Clin. exp. Immunol. 16: 295-300
• Nomura, T., T. Nagata, Y. Kawamura, Y. Sawai (1989) A case of severe yamakagashi (Rhabdophis tigrinus) bite treated by antivenom. Snake 21: 85-86
• Ogawa, H., Y. Sawai (1986) Fatal bite of the yamakagashi (Rhabdophis tigrinus). Snake 18: 53-54
• Pope, C. H. (1958 ) Fatal bite of captive African rear-fanged snake (Dispholidus). Copeia 4: 280-282
• Saddler, M., B. Paul (1988) Vine snake envenomation. Cent. Afr. J. Med. 34: 31-33
• Spies, S. K., L. F. Malherbe, W. J. Pepler (1962) Boomslangbyt met afibrinogenemia. S. Afr. med. J. 36: 864-870
• Visser, J., D. S. Chapman (1978) Snakes and snake bite. Venomous snakes and management of snake bite in Southern Africa. Purnell, Cape Town: 152