Scorpion envenomation: does antivenom reduce serum venom concentrations?
- Bernard Foëx, Consultant in Emergency Medicine and Critical Care,
- Lee Wallis, Consultant in Emergency Medicine
Abstract
A short cut review was carried out to determine if anitvenom reduces serum venom concentrations. Using the reported search, 69 papers were found, of which four presented the best evidence to answer the clinical question. The author, date, and country of publication, patient group studied, study type, relevant outcomes, results, and study weaknesses of these best papers are tabulated. A clinical bottom line is stated.
Report by Bernard Foëx, Consultant in Emergency Medicine and Critical Care Checked by Lee Wallis, Consultant in Emergency Medicine
Clinical scenario
A woman has been stung by a scorpion while buying bananas in her local supermarket. She is showing some signs of systemic envenomation and you wonder whether giving her antivenom will reduce her serum venom concentration.
Three part question
In [scorpion envenomation] does [antivenom serotherapy] [reduce serum venom concentration]?
Search strategy
Medline 1966-11/04 using the OVID interface. [exp Scorpions OR scorpion.mp OR exp Scorpion Venoms OR scorpion venom.mp OR scorpionism.mp] AND [envenoming.mp OR envenomation.mp] AND [exp Antivenins OR antivenom.mp OR exp Immunization, Passive OR serotherapy.mp OR exp Immunoglobulins, Fab] LIMIT to human AND English language
Search outcome
Altogether, 69 papers were found, only four of which addressed the serum kinetics of scorpion venom after administration of antivenom.
Comment(s)
The vast majority of patients had only grade I envenomation. Serum venom concentrations were higher in grade II than grade I envenomations.
Two studies showed that one dose of antivenom administered intramuscularly was not effective in reducing serum venom concentrations. Intravenous antivenom was effective in reducing serum venom concentrations compared to controls in two studies. Higher doses were more effective. Two studies documented clinical improvements with antivenom treatment.
CLINICAL BOTTOM LINE
There is good evidence that intravenous administration of antivenom reduces serum venom concentrations. Whether this is clinically relevant is open to question.
Report by Bernard Foëx, Consultant in Emergency Medicine and Critical Care Checked by Lee Wallis, Consultant in Emergency Medicine
