[Pediatric adder bites]

Abstract

Adder bites and their progression to severe envenomations are more frequent in children than in adults.

Aim: To describe the clinical, biological, and therapeutic characteristics of children bitten by adders and to identify risk factors associated with severe envenomations corresponding to grades II and III of the Audebert et al. classification (Toxicon 1992).

Material and methods: A retrospective study was conducted between 2001 and 2009 in the pediatric emergency department of a tertiary children's hospital. The data collected were: age and sex of children; day and time of admission; day, time, and circumstances of the accident; snake identification; bite location; envenomation severity based on the Audebert et al. classification; presence of fang marks; prehospital care; use of specific immunotherapy (Viperfav(®)), associated treatments; length of stay; orientation, progression, and any complications.

Results: Fifty-eight children were included (43 boys, 15 girls). The mean age was 7.8 ± 4.1 years (range, 1.8-15 years). Bites occurred more often between 12:00 pm and 6:00 pm (62%), and were most often located in the lower extremities (77%). The classification of envenomation was: 83% low grade (grade 0, absence of envenomation, fang marks present; grade I, minor envenomation) and 17% high grade (grades II and III, moderate and severe envenomations). All high-grade envenomations received specific immunotherapy (Viperfav(®) F(ab')(2) fragments against Vipera aspis, Vipera berus, and Vipera ammodytes). The mean time from bite to Viperfav(®) injection was 23 ± 11 h (range, 8-36 h). Being bitten on the upper extremities (p < 0.001), during the afternoon (p = 0.025), feeling an immediate violent pain (p = 0.037), and high initial glycemia (p = 0.016) were associated with a significant risk of progressing to high-grade envenomation. There was no significant correlation between age, gender, and upper extremity bite. In the final model of the multivariate statistical analysis, three factors remained associated with this risk: bite location in the upper extremities (relative risk [RR] = 60.5 [3.5-1040[; p = 0.005), immediate violent pain (RR = 21.5 [1.3-364.5[; p = 0.03), and female gender (RR = 17.5 [0.9-320.3[; p = 0.053).

Conclusion: A certain number of criteria seem related with a more significant risk of progression to high-grade envenomation following an adder bite. These results need to be studied on a larger cohort of patients. Bites to the upper extremities should be handled with caution because of the association with more severe envenomation.