Severe acute pulmonary haemorrhage and haemoptysis in ten dogs following eastern brown snake (Pseudonaja textilis) envenomation: Clinical signs, treatment and outcomes

Immunoreactivity of eastern small eyed snake (Cryptophis nigrescens) venom towards species-specific antibodies of five medically important venomous Australian elapids

The eastern small eyed snake (Cryptophis nigrescens; CN) is an uncommon cause of snakebite in Australia despite the widespread distribution of the snake along the east coast of Australia. Diagnosis of envenomation relies on identification of the snake which is often not possible with animal snakebite cases. This study examined the immunoreactivity profile of CN venom towards specific rabbit IgG made against the medically relevant snake venom immunotypes found in Australia (tiger, brown, black, death adder and taipan). A simultaneous sandwich ELISA format was used to quantify CN venom binding to venom specific Protein A purified rabbit IgG. The binding profiles demonstrated weak binding of CN venom to rabbit IgG made against both tiger (N. scutatus) and black snake (P. australis) venoms with approximately 0.19% and 0.069% cross reactivity, respectively. However, the concentration of venom likely to be present in the urine of CN envenomed patients and the low cross reactivity suggest that envenomed veterinary patients are unlikely to be detected in the commercial snake venom detection kit. It is possible that CN envenomation is more common but may be underdiagnosed where snake venom antigen detection is relied upon solely. Serum biochemical abnormalities also overlap with other snake species found in the same geographical area. In respect of antivenom therapy, administration of tiger snake antivenom is supported by the binding data, but due to the low cross reactivity multiple vials may be required. Limited clinical evidence also supports the efficacy of tiger snake antivenom for envenomation by CN.

Mechanical ventilation in snake envenomation of dogs and cats

Envenomation by snakes in Elapidae and Viperidae families have been associated with respiratory failure in dogs and cats. Mechanical ventilation may be required for hypoventilation due to neuromuscular paralysis or hypoxemia due to pulmonary hemorrhage or aspiration pneumonia. Median incidence of dogs and cats with snake envenomation that require mechanical ventilation is 13% (0.06-40%). Standard treatment of snake envenomation in dogs and cats includes prompt administration of appropriate antivenom and management of envenomation complications such as coagulopathy, rhabdomyolysis and acute kidney injury. When mechanical ventilation is required, overall prognosis is good with appropriate treatment. Standard anesthetic protocols and mechanical ventilator settings are generally appropriate, with lung protective ventilation strategies typically reserved for patients with pulmonary disease. Median survival to discharge for cats and dogs with elapid envenomation is 72% (76-84%) with 33 h (19.5-58 h) median duration of mechanical ventilation and 140 h (84-196 h) median hospitalization. This article reviews indications for mechanical ventilation in cats and dogs with snake envenomation, and discusses ventilator settings, anesthetic and nursing considerations, complications and outcomes specific to this disease.

Successful treatment of a potentially fatal eastern brown snake (Pseudonaja textilis) envenomation in a dog with tiger-brown snake antivenom with serial quantification of venom antigen and antivenom concentrations in serum and urine

CASE REPORT

A successfully treated case of eastern brown snake (Pseudonaja textilis) envenomation in a Jack Russel Terrier dog is described with measurement of venom and antivenom concentration pre- and post-treatment. Early presentation, prompt administration of tiger-brown snake antivenom, hospitalisation and critical care monitoring lead to low morbidity and rapid recovery from a potentially fatal envenomation. Retrospective measurement of urine and serum venom and antivenom provided insight into the potential severity of the case and rapid efficacy of antivenom.

CLINICAL SIGNIFICANCE

Potentially fatal brown snakebite cases may initially present with only mild clinical signs despite having high concentrations of venom and potential for fatal outcome. Prompt treatment with antivenom is essential to prevent the development of progressive and fatal coagulopathy and paralysis.

Coagulation factor activity patterns of venom-induced consumption coagulopathy in naturally occurring tiger snake (Notechis scutatus) envenomed dogs treated with antivenom

BACKGROUND

Venom-induced consumption coagulopathy (VICC) from tiger snake (Notechis scutatus) envenomation results in a dose-dependent coagulopathy that is detectable on coagulometry. However, individual coagulation factor activities in dogs with tiger snake envenomation have not been determined. This study aimed to characterise VICC and the time course of recovery in tiger snake envenomed dogs and to investigate an association between tiger snake venom (TSV) concentrations and factor activity.

METHODS

This was a prospective, observational, cohort study. The study cohort was 11 dogs of any age, breed, sex, body weight >10 kg, confirmed serum TSV on ELISA and treated with antivenom. Blood was collected at enrolment before antivenom administration, then at 3, 12 and 24 h after antivenom administration. Tiger snake venom concentrations were detected with a sandwich ELISA. Fibrinogen was measured using a modified Clauss method, and coagulation factors (F) II, V, VII, VIII and X were measured with factor-deficient human plasma using a modified prothrombin (PT) and activated partial thromboplastin (aPTT) method. Linear mixed models, with multiple imputations of censored observations, were used to determine the effect of time and TSV concentration on the coagulation times and factor activity. This cohort was compared to 20 healthy controls.

RESULTS

At enrolment, there were severe deficiencies in fibrinogen, FV and FVIII, with predicted recovery by 10.86, 11.75 and 13.14 h after antivenom, respectively. There were modest deficiencies in FX and FII, with predicted recovery by 20.57 and 32.49 h after antivenom, respectively. No changes were detected in FVII. Prothrombin time and aPTT were markedly prolonged with predicted recovery of aPTT by 12.58 h. Higher serum TSV concentrations were associated with greater deficiencies in FII, FV and FVIII, and greater prolongations in coagulation times. The median (range) serum TSV concentration was 57 (6-2295) ng/mL.

CONCLUSIONS

In tiger snake envenomed dogs, we detected a profound, TSV-concentration-related consumption of select coagulation factors, that rapidly recovered toward normal. These findings allowed further insight into tiger snake VICC in dogs.

Systemic bleeding including pulmonary haemorrhage following hump-nosed pit viper (Hypnale hypnale) envenoming: A case report from Sri Lanka

Out of seven venomous land snake species of Sri Lanka, hump-nosed pit viper (Hypnale spp.) causes the commonest venomous snakebites. It is widely distributed all over the country except in the peninsula of Jaffna. The genus has three species naming H. hypnale, H. zara and H. nepa. They frequently cause local envenoming and rarely cause coagulopathy and acute kidney injury. Systemic bleeding is the most trivial complication associated with coagulopathy caused by these snakes and pulmonary haemorrhages are one of them which are rarely reported. Antivenoms are currently not available for genus Hypnale bites in Sri Lanka. We describe a fatal case of pulmonary haemorrhage caused by a proven hump-nosed viper (Hypnale hypnale) bite associated with other systemic bleeding manifestations and thrombotic microangiopathy. This is the first known case of pulmonary and intracranial haemorrhages caused by hump-nosed viper bite.