Non-venomous snake bite and snake bite without envenoming in a brazilian teaching hospital: analysis of 91 cases

Abstract

A retrospective survey of 473 cases of snake bite admitted to a Brazilian teaching hospital from 1984 to 1990 revealed 91 cases of bite without envenoming and/or caused by non-venomous snakes. In 17 of these cases the snake was identified, and one patient was bitten by a snake-like reptile (Amphisbaena mertensii). In 43 cases diagnosis was made on clinical grounds (fang marks in the absence of signs of envenoming). The other 30 cases were of patients who complained of being bitten but who did not show any sign of envenoming or fang mark. Most cases occurred in men (66;73%), in the 10-19 years age group (26;29%), in the lower limbs (51/74;69%), between 6 A. M. and 2 P.M. (49;61%) and in the month of April (16; 18%). One patient bitten by Philodryas olfersii developed severe local pain, swelling and redness at the site of the bite, with normal clotting time. The patient bitten by Drymarcon corais was misdiagnosed as being bitten by a snake of the genus Bothrops, was given the specific antivenom, and developed anaphylaxis. One patient bitten by Sibynomorphus mikanii presented prolonged clotting time, and was also given antivenom as a case of Bothrops bite. Correct identification of venomous snakes by physicians is necessary to provide correct treatment to victims of snake bite, avoiding unnecessary distress to the patient, and overprescription of antivenom, which may eventually cause severe untoward effects.

Incidence and mortality due to snakebite in the Americas

“…Asymptomatic snakebites may result either from a bite by a non-venomous snake or a venomous one that did not inject venom (dry bite). According to the countries and authors, asymptomatic snakebites represent between 10 and 40%, about one third of which are dry bites [7; 63; 64]. …”

“…The bites by opistoglyphic (rear fanged) snakes and those of the families lacking fangs delivering venom (Boidae, Aniilidae in particular) being weakly toxic [6], represent a low demand for health services, although the incidence is far from trivial [7]. The snakes belonging to the Scolecophidia suborder (Typhlopidae and Leptotyphlopidae) are definitely non-toxic and unable to bite.…”

Perfil dos acidentes ofídicos no norte do Estado de Minas Gerais, Brasil

“…Quanto ao tipo de serpente, 9.715 (92%) notificações não incluíram o tipo de serpente que causou o acidente. Esse dado pode ser justificado pelo desconhecimento da população, dos médicos, dos enfermeiros, dos auxiliares de enfermagem e dos agentes comunitários de saúde sobre as características que são importantes na identificação dos tipos de serpentes 22 .…”

Envenomation by the neotropical colubrid Boiruna maculata (Boulenger, 1896): a case report

“…Patients bitten by colubrids and present local manifestations are usually treated with Bothrops antivenom 16,17,20 . In this case, despite the snake identification, the patient was treated with Bothrops antivenom.…”