Acute Kidney Injury in Dogs with Pit Viper Envenomation

Pit viper envenomation is a common veterinary emergency in certain parts of the United States.^1,2 Clinical signs may range from mild local reactions to profound cardiovascular dysfunction and death. Acute kidney injury (AKI) has been reported in human patients after pit viper envenomation and in veterinary patients secondary to envenomation by other species of snakes.^3,4 Although the mechanism for AKI following pit viper envenomation is unknown, proposed causes include a combination of distributive shock, hypovolemic shock from hemorrhage, and decreased cardiac output as a result of the effect of venom on the myocardium.¹ 

In this retrospective study, authors investigated the incidence of AKI in dogs diagnosed with North American pit viper envenomation and evaluated the association of AKI with length of hospitalization, antivenom dose received, and survival. 

Medical records from 2008 to 2017 of dogs with pit viper envenomation were evaluated. To be included, dogs had to have received at least one vial of crotalid polyvalent antivenom and 2 plasma creatinine measurements within 48 hours of hospitalization. Fifty-six dogs were included; of those, 16 (29%) developed AKI during hospitalization. The type of antivenom received was not associated with AKI, but dogs that developed AKI received significantly higher doses of antivenom (8.7 ± 6.8 vials) as compared with dogs that did not develop AKI (4.2 ± 2.6 vials). Dogs in the AKI group were also significantly more tachycardic (198 ± 47 vs 159 ± 48), were more likely to receive packed RBC transfusions (56% vs 27%), and had a higher shock index (heart rate/systolic blood pressure; 2.6 ± 1.2 vs 1.6 ± 1.2). Development of AKI was significantly associated with outcome, with only 5 (31%) dogs with AKI surviving to discharge, whereas 39 (98%) dogs survived to discharge in the non-AKI group. There was no significant association found between the development of AKI and length of hospitalization. 

Key pearls to put into practice:

AKI is not an uncommon complication after pit viper envenomation in dogs. The incidence in this study was 29%; however, this study only included dogs that received antivenom therapy. It is possible that the incidence of AKI might have been lower if all dogs with snake envenomation were included in the evaluation, including those not treated with antivenom.

Even small increases in creatinine might be significant in dogs with pit viper envenomation. According to International Renal Interest Society guidelines, AKI is defined as a serum creatinine of >1.6 mg/dL or an absolute serum creatinine concentration increase of ≥0.3 mg/dL from baseline within 48 hours.⁵ Clinicians should consider re-evaluation of laboratory parameters 24 to 48 hours after pit viper envenomation.

Dogs with envenomation that are presented with tachycardia, require more vials of antivenom, require packed RBC transfusions, or have a high shock index are more likely to develop AKI.