Australian taipan (Oxyuranus spp.) envenoming: clinical effects and potential benefits of early antivenom therapy – Australian Snakebite Project (ASP-25)

Abstract

Context: Taipans (Oxyuranus spp.) are medically important venomous snakes from Australia and Papua New Guinea. The objective of this study was to describe taipan envenoming in Australian and its response to antivenom.

Methods: Confirmed taipan bites were recruited from the Australian Snakebite Project. Data were collected prospectively on all snakebites, including patient demographics, bite circumstances, clinical effects, laboratory results, complications and treatment. Blood samples were taken and analysed by venom specific immunoassay to confirm snake species and measure venom concentration pre- and post-antivenom.

Results: There were 40 confirmed taipan bites: median age 41 years (2–85 years), 34 were males and 21 were snake handlers. Systemic envenoming occurred in 33 patients with neurotoxicity (26), complete venom induced consumption coagulopathy (VICC) (16), partial VICC (15), acute kidney injury (13), myotoxicity (11) and thrombocytopenia (7). Venom allergy occurred in seven patients, three of which had no evidence of envenoming and one died. Antivenom was given to 34 patients with a median initial dose of one vial (range 1–4), and a median total dose of two vials (range 1–9). A greater total antivenom dose was associated with VICC, neurotoxicity and acute kidney injury. Early antivenom administration was associated with a decreased frequency of neurotoxicity, acute kidney injury, myotoxicity and intubation. There was a shorter median time to discharge of 51 h (19–432 h) in patients given antivenom <4 h post-bite, compared to 175 h (27–1104 h) in those given antivenom >4 h. Median peak venom concentration in 25 patients with systemic envenoming and a sample available was 8.4 ng/L (1–3212 ng/L). No venom was detected in post-antivenom samples, including 20 patients given one vial initially and five patients bitten by inland taipans.

Discussion: Australian taipan envenoming is characterised by neurotoxicity, myotoxicity, coagulopathy, acute kidney injury and thrombocytopenia. One vial of antivenom binds all measurable venom and early antivenom was associated with a favourable outcome.

Keywords:

• Australia
• snakebite
• taipan
• envenoming
• antivenom

Acknowledgements

We acknowledge all of the medical, nursing and laboratory staff involved in recruiting patients to the Australian Snakebite Project. We thank Ms Renai Kearney for data collation and data entry for patients in the study.

Disclosure statement

C.I.J. is a salaried employee of Boehringer Ingelheim. This work was carried out independently from employment at Boehringer Ingelheim; Boehringer Ingelheim did not have any role in the design, completion, review or publication of this study.

Funding

The study was funded by an NHMRC Program [grant No. 1055176]. Nicole Ryan is funded by an NHMRC Early Career Fellowship Award ID 1072056. Simon Brown is funded by an NHMRC Career Development Fellowship ID 1023265. Geoff Isbister is funded by an NHMRC Senior Research Fellowship ID 1061041.