Clinical effects of red-bellied black snake (Pseudechis porphyriacus) envenoming and correlation with venom concentrations: Australian Snakebite Project (ASP-11).

OBJECTIVE: To describe the clinical features and laboratory findings in patients with definite red-bellied black snake (RBBS; Pseudechis porphyriacus) bites, including correlation with results of venom assays. DESIGN, PATIENTS AND SETTING: Prospective cohort study of patients with definite RBBS bites, recruited to the Australian Snakebite Project from January 2002 to June 2010. MAIN OUTCOME MEASURES: Clinical and laboratory features of envenoming; peak venom concentrations and antivenom treatment. RESULTS: There were 81 definite RBBS bites; systemic envenoming occurred in 57 patients (70%) and local envenoming alone occurred in one patient. Systemic envenoming was characterised by local envenoming in 55 patients (96%), systemic symptoms in 54 patients (95%), anticoagulant coagulopathy with a raised activated partial thromboplastin time (aPTT) in 35 patients (61%) and myotoxicity in seven patients (12%). One patient required non-invasive ventilation for severe myotoxicity that resulted in muscle weakness. Three patients developed local ulceration. There were no deaths. Twenty-two envenomed patients (39%) received tiger snake or black snake antivenom, and administration within 6 hours of the bite was associated with normalisation of the aPTT. Eight patients (36%) had immediate hypersensitivity reactions to antivenom, including one case of anaphylaxis. The median peak venom concentration in 37 systemically envenomed patients with serum available was 19 ng/mL (interquartile range, 12-50 ng/mL; range, 3-360 ng/mL), which did not correlate with clinical severity. In 17 patients who received antivenom and had venom concentration measured, no venom was detected in serum after the first antivenom dose, including nine who were given one vial of tiger snake antivenom. CONCLUSION: RBBS envenoming caused local effects, systemic symptoms, anticoagulant coagulopathy and, uncommonly, myotoxicity. One vial of tiger snake or black snake antivenom appears to be sufficient to remove venom and neutralise reversible effects, but hypersensitivity reactions occurred in over a third of patients.

Envenoming by the rough-scaled snake (Tropidechis carinatus): a series of confirmed cases.

OBJECTIVE: To describe demographic, geographical and clinical features of envenoming by the rough-scaled snake (RSS) (Tropidechis carinatus). DESIGN, SETTING AND PARTICIPANTS: Prospective cohort study of RSS snakebite victims, recruited between January 2004 and December 2008, as part of the Australian Snakebite Project. RSS envenoming cases were confirmed by snake identification and/or venom-specific enzyme immunoassay. MAIN OUTCOME MEASURES: Clinical and laboratory features of envenoming. RESULTS: There were 24 confirmed cases of RSS envenoming, nearly all occurring in coastal areas between northern New South Wales and south-eastern Queensland. Twenty-three patients had local bite-site effects and 17 had at least three non-specific systemic effects (eg, nausea, headache). All 24 had venom-induced consumption coagulopathy (VICC), and 19 had an international normalised ratio>3.0. Six had bleeding from the bite site or intravenous cannula site, 10 had blood detected on urinalysis, and one had a major intra-abdominal haemorrhage. Mild neurotoxicity developed in two patients, and one patient developed myotoxicity with generalised myalgia, myoglobinuria and a peak creatine kinase level of 59 700 IU/L. Twenty-three patients were treated with antivenom (21 with tiger snake antivenom, two with polyvalent antivenom). Free venom was undetectable in 19 of 20 blood samples taken after antivenom administration. CONCLUSION: RSS envenoming occurs predominantly in coastal areas of northern NSW and southern Queensland, and within this range, most envenoming is due to the RSS rather than tiger snakes. Clinically it is characterised by VICC, with mild neurotoxicity and myotoxicity in some cases. Tiger snake antivenom appears to be effective against RSS envenoming.