23 September 2019

Snake bite deaths spark questions over treatment

Extreme Medicine Research

One vial of antivenom may be the Australian recommendation for treating a snake bite but it may not be enough to save lives, experts warn.

A perspective published today in the MJA cited two recent deaths in Australia from tiger snake bites, both of which were treated with multiple vials of antivenom.

The coroner who examined the deaths concluded that: “In treating an envenomed patient we need to successfully treat the ‘outlier’ case, not the ‘median’ case.”

The toxicologist’s report ruled that two vials of antivenom as an initial dose was justified.

“It is arguable whether additional antivenom would have had therapeutic benefit for this patient, but providing it earlier is highly desirable because this could conceivably neutralise sequestered venom as it is absorbed from the bite site and may therefore bind circulating venom toxins as they enter the vascular system,” the authors said.

While antivenom remains a cornerstone of treatment for a snake bite, it is encouraged that it be supplemented with intensive care medicine, mechanical ventilation and haemodialysis.

“The Australian medical community should be aware that there is no consensus agreement that one vial of any Australian snake antivenom is all that is ever required for significant Australian elapid envenoming,” the authors said.

But for patients who were elderly, young children, or people with comorbidities, treating them with multiple vials of antivenom could expose them to unnecessary risk and reduce the likelihood of a positive outcome.

But there was no evidence indicating that higher doses of antivenom were dangerous.

In addition, the authors warned that multiple vial doses, such as occurred in the two recent casualties, should not be routinely used for all patients requiring antivenom.

“Each envenomed patient should be individually assessed and provided with adequate antivenom in response to the envenoming severity and their individual clinical needs,” they concluded.