Viper Bites in France: Clinical and Biological Evaluation;Kinetics of Envenomations

Abstract

1 A second inquiry was conducted in France to collect more accurate epidemiological, clinical and biological data from patients hospitalized after a viper bite, as well as treatment that they received. Fifty-seven well documented cases were classified in four grades of increasing severity defined according to the clinical signs of envenomation.

2 Local and systemic signs of envenomation appeared during the first 3 h, but the severity of the envenomation was observed to increase during the 12-24 h following bites in 50% of moderate and severe cases. One fatal case was reported. Biological analysis revealed an hyperleukocytosis in patients with moderate and severe envenomations.

3 The average length of hospitalization was of 1.7 ± 1.3 days for patients without signs of envenomation (grade 0) or presenting a minimal envenomation (grade 1), and statistically longer, 6.2 ± 2.9 days, for patients presenting moderate (grade 2) or severe envenomation (grade 3).

4 Levels of venom antigens in serum samples regularly collected during hospitalization were determined by a sandwich ELISA test. The serum venom levels determined during the first 4 h following the bite correlated with the severity of the envenomation when the symptoms were determined at their worst, usually 12-24 h later. In fact, concentrations higher than 20 ng ml^-1 predict a moderate or severe clinical evolution.

5 The pharmacokinetics of venom antigens was also investigated during human envenomations. Venom antigens could be detected in the serum of patients as soon as half an hour after the bite, then decreased exponentially during the following hours with an apparent half-life of 8 h, similar in grade 2 and grade 3 patients, indicating that the kinetics of venom antigens in blood is independent of the severity of the envenomation.