Clinical findings associated with prairie rattlesnake bites in dogs: 100 cases (1989-1998).

Objective: To identify clinically relevant variables and treatments for dogs bitten by prairie rattlesnakes (Crotalus viridis viridis).

Design: Retrospective study.

Animals: 100 client-owned dogs.

Procedure: Records of dogs evaluated for rattlesnake envenomation from 1989 to 1998 were reviewed. Analysis was performed to test for significant associations among clinical variables or treatments and cell counts, costs, and duration of hospitalization.

Results: Most prairie rattlesnake bites occurred between May and September. Dogs were 3 months to 12 years old (median, 3.7 years); most were bitten on the head in the late afternoon. There was no sex predilection. Median time to evaluation was 1 hour (range, 15 minutes to 13 hours). Swelling in the area of the bite was the primary physical abnormality. Principal initial laboratory findings were echinocytosis, thrombocytopenia, leukocytosis, and prolonged activated clotting time. Ninety-four dogs were hospitalized; 48 were discharged the following day. Antimicrobials and crystalloid fluids, glucocorticoids, antihistamines, and antivenin administered i.v. were the most commonly used treatments. One dog died, and small dogs were hospitalized longer than large dogs. Antivenin administration was not significantly associated with duration of hospitalization but was associated with higher platelet counts after treatment and higher total hospital costs.

Conclusions And Clinical Relevance: Prairie rattlesnake envenomation in dogs is associated with high morbidity rate but low mortality rate. The efficacy of administration of antivenin for dogs with bites from this snake species is questionable.