A review of 91 canine and feline red‐bellied black snake (Pseudechis porphyriacus) envenomation cases and lessons for improved management

Abstract

Introduction Most cases of red-bellied black snake (RBBS) envenomation in dogs respond favourably to treatment comprising of tiger-brown snake antivenom (TBAV), intravenous fluid therapy, analgesia and, if indicated, mechanical ventilation and/or blood transfusion. However, there remains a subset of patients who develop fatal complications despite intensive treatment and risk factors for these occurring remain unknown. Here we present a retrospective crosssectional survey of 91 canine and feline RBBS envenomation cases.Methods Cases seen between June 2010 and June 2020 were retrieved from the databases of seven practices in South East and coastal Queensland. From the canine case population, logistic regression analysis was performed to assess the impact of potential risk factors at presentation on the likelihood of death. A final multivariable model was developed using a manual backwards elimination approach based on overall likelihood ratio tests and Wald chi-square P-values for each variable. Where model convergence failed due to quasicomplete separation, Firth's penalised maximum likelihood method was implemented. Such separation may occur when an outcome is completely predicted by an explanatory variable in one group. ResultsOf the 88 canine cases, 7 died (8.0%), all after prognosis-based euthanasia. Of the three feline cases, one died after unsuccessful resuscitation following cardiopulmonary arrest. Compared to survivors, dogs that died were older, exhibited pigmenturia, received antivenom later and had a higher total plasma protein (TPP), activated clotting time (ACT) and lower packed cell volume (PCV) at presentation.

Mechanical ventilation in snake envenomation of dogs and cats

“…In a study of dogs and cats envenomated by P. porphyriacus , ventilated patients did not require more antivenom compared to non-ventilated patients ( 4 ). There was no significant difference between number of vials of antivenom and length of hospitalization or survival in another study of dogs and cats undergoing MV for rattlesnake envenomation ( 6 ).…”

“…No significant complications including AKI, cardiac arrhythmias, SIRS, MODS or hemorrhage were reported in any patient receiving antivenom within 6 h of being bitten by P. porphyriacus (4). Early administration of antivenom in envenomated patients has been shown to reduce the incidence of complications (132).…”

“…Hypoventilation requiring MV has been documented in one case of Pseudechis prophyriacus envenomation ( 16 ). Hypoxemia secondary to pulmonary hemorrhage is a more common indication for MV in envenomation by this species ( 4 , 7 ).…”

“…In Australian elapids, bite sites are often not found due to small sized fangs and minimal localized swelling in combination with thick hair coats of cats and dogs ( 34 ). Other common clinical signs include vomiting, hypersalivation, diarrhea, tachypnea, collapse, mydriasis, ataxia, and pigmenturia ( 4 , 19 , 33 , 35 ).…”

“…There is a paucity of evidence in the veterinary literature on the ideal use of mechanical ventilation (MV) for cats and dogs undergoing treatment for snake envenomation. The median incidence of dogs and cats with snake envenomation that require MV is 13% (0.06-40%) (2)(3)(4)(5)(6)(7)(8)(9)(10).…”