Monday, August 6, 2012

Snake bite victims given wrong treatment

The tiger snake, Notechis scutatus.

The following story is from the Australia media outlet 9News, but the original article it is based upon is cited at the bottom of the post with a link.

Many snake-bite victims have been given the wrong antivenom because of flaws in a common test for tiger snake venom, a study shows.

An analysis of tiger snake bite cases between 2004 and 2011 has found the sVDK test used to detect the venom is unreliable.

A quarter of the cases tested negative for tiger snake venom, and in four cases patients were given anti-venom for brown snake bites instead.

Fortunately there were no adverse effects because brown snake antivenom can provide protection against poison from several snake species.

The study, led by toxicologist Associate Professor Geoffrey Isbister of the University of Newcastle, also found some bite victims had been given four or more vials of tiger snake antivenom, when one vial - as initially recommended by manufacturer CSL - was sufficient.

A total of 56 tiger snake bites were identified over the seven-year period from a database drawn from more than 100 Australian hospitals.

Nine of the bites were inflicted by snakes in captivity.

Nearly all victims suffered blood-clotting abnormalities, a third suffered neurotoxicity which affected nerves, while nausea, vomiting and headache were common symptoms.

No deaths were reported.

"Our study brings into question the reliance on the sVDK test for determining appropriate antivenom treatment," the report on the study, published in the Medical Journal of Australia, says

"The sVDK result was incorrect in five out of 44 cases, giving a positive result for brown snake venom, which led to the incorrect use of antivenom in four of the five cases.

"The use of sVDK is thus problematic and may confuse clinical assessment," the authors say.

The data shows one vial of antivenom to treat tiger snake bites is an adequate dose, they say.

Geoffrey K Isbister, Margaret A O’Leary, Matthew Elliott and Simon G A Brown. 2012. Tiger snake (Notechis spp) envenoming: Australian Snakebite Project (ASP-13). Med J Aust 2012; 197 (3): 173-177

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