Bites by Tomodon dorsatus (serpentes, dipsadidae): clinical and epidemiological study of 86 cases

Abstract

A total of 86 proven cases ofTomodon dorsatusbites admitted to Hospital Vital Brazil (HVB) of ButantanInstitute, in São Paulo, Brazil, between 1945 and 2018, were retrospectively analyzed. The cases included werethose in which the snake was brought to HVB and was correctly identified. Of the 86 cases of snake bites, it waspossible to describe the sex of the snake in 52 cases; 31 (59.6%) snakes were male. Only 52 snakes out of 86could be studied because of their preservation status. The length of snakes (snout–vent length) ranged from 180to 770 mm. Of the 86 snakes, 72 could be distinguished as adults (n = 63, 87.5%) or juveniles (n = 9, 12.5%).Most bites occurred in the spring and summer seasons (n = 57, 66.3%) and during warmer periods of the day(n = 61, 72.6%), between 9A.M. and 3P.M. The mean ( ± standard deviation) age of the victims was 26.9 ± 17.2 years, and 60 (69.8%) were men.Approximately 90% of the patients sought medical care within 6 h after the bite. Both upper (n = 45, 52.3%)and lower (n = 37, 43.0%) limbs were the most frequently bitten, particularly the feet and hands (n = 54,62.8%). The local clinical manifestations were pain (n = 55, 64.0%), transitory bleeding (n = 23, 26.7%), er-ythema (n = 22, 25.6%), edema (n = 14, 16.3%), paresthesia (n = 9, 10.5%), and ecchymosis (n = 3, 3.5%).Only 10 (11.6%) patients reported non-specific systemic symptoms characterized by transient dizziness or mildheadache, and 21 (24.4%) patients showed no evidence of envenomation. A 20 min whole blood clotting test wasperformed in 31 (36.0%) patients on admission and all of them had coagulable blood. Supportive treatment wasoffered to 38 (44.2%) patients, namely, antiseptic (n = 20, 23.3%), antihistamines (n = 12, 14.0%), and an-algesics (n = 9, 10.5%). Four (4.7%) patients were inappropriately treated withBothropsantivenom before theiradmission to HVB. No sequelae or relevant complications were observed in patients, and the prognosis wasbenign. Therefore, althoughT. dorsatusbites can cause mild local symptomatology, it is important that healthprofessionals know how to make the correct diagnosis to avoid unnecessary use of antivenom.