Thromboelastographic evaluation of dogs bitten by rattlesnakes native to southern California

Abstract

OBJECTIVE To validate that dogs become hypocoagulable following rattlesnake envenomation and to determine whether thromboelastographic abnormalities are correlated with envenomation severity for dogs bitten by rattlesnakes native to southern California. ANIMALS 14 dogs with observed or suspected rattlesnake envenomation (envenomated dogs) and 10 healthy control dogs. PROCEDURES For each dog, a citrate-anticoagulated blood sample underwent kaolin-activated thromboelastography. For each envenomated dog, a snakebite severity score was assigned on the basis of clinical findings, and prothrombin time, activated partial thromboplastin time, and platelet count were determined when the attending clinician deemed it necessary and owner finances allowed. RESULTS For 12 of 14 envenomated dogs, the thromboelastographically determined clot strength was below the 25th percentile for the clot strength of control dogs, which was indicative of a hypocoagulable state. No envenomated dog had thromboelastographic results indicative of a hypercoagulable state. One envenomated dog had a prolonged prothrombin time, but the activated partial thromboplastin time and all thromboelastographic variables were within the respective reference ranges for that dog. Seven of 13 envenomated dogs were thrombocytopenic (platelet count, ≤ 170,000 platelets/μL). Snakebite severity score was negatively correlated with platelet count but was not correlated with any thromboelastographic variable. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that dogs generally become hypocoagulable following rattlesnake envenomation. Thromboelastography might provide an objective measure of the coagulation status of envenomated dogs and aid in the identification of dogs that are in a hypocoagulable state and in need of antivenin treatment prior to the onset of progressive clinical signs.

Hemostatic Analysis of Simulated Gloydius ussuriensis Envenomation Using Canine Blood: A Comparison of Thromboelastography and Classical Coagulation Tests

“…This phenomenon is termed venom-induced consumptive coagulopathy (VICC) because of its shared similarity with disseminated intravascular coagulopathy (DIC); however, it does not trigger severe organ damage or systemic thrombosis, which is common in DIC [13]. Animals with VICC usually exhibit pathological abnormalities, such as prolonged prothrombin time (PT), activated partial thromboplastin time (aPTT), low fibrinogen and antithrombin concentrations, elevated D-dimer levels, and thrombocytopenia [14][15][16][17]. However, laboratory results of classical coagulation tests (CCTs) are frequently normal in the initial stages and gradually become abnormal within a few hours to days [14,18,19].…”

“…Its usefulness ranges from transfusion in trauma patients to monitoring hemostasis during liver transplantation and cardiac surgeries [21,22]. In veterinary medicine, researchers have reported on the use of TEG during the diagnosis and treatment of VICC along with CCTs [14][15][16][17]. However, they have not compared the efficacy of TEG with that of CCTs.…”

Thromboelastographic evaluation of 2 dogs with boomslang (Dispholidus typus) envenomation

“…[11][12][13] More specific conditions relevant to that presented herein include TEG evaluation of hemostatic function in dogs with DIC, the use of TEG to assess hemostatic changes in dogs naturally envenomed by the African puffadder (Bitis arietans) and snouted cobra (Naja annulifera), and TEG evaluation of dogs bitten by rattlesnakes native to southern California. [14][15][16] The use of TEG in cases of boomslang envenomation in people has been reported; however, to the authors' knowledge, no such reports exist in the veterinary literature. (or sometimes referred to as stage IV of DIC).…”

“…As a result, TEG has grown in popularity and has subsequently been demonstrated to be a useful tool in both the diagnosis and management of various hemostatic abnormalities in dogs, correlating with clinical signs of bleeding 11–13 . More specific conditions relevant to that presented herein include TEG evaluation of hemostatic function in dogs with DIC, the use of TEG to assess hemostatic changes in dogs naturally envenomed by the African puffadder ( Bitis arietans ) and snouted cobra ( Naja annulifera ), and TEG evaluation of dogs bitten by rattlesnakes native to southern California 14–16 …”

Rattlesnake envenomation in 2 Visayan warty pigs

“…Thromboelastographic evaluation of dogs bitten by rattlesnakes revealed that most envenomated animals had a clot strength below the 25th percentile (compared to control dogs), suggestive of a hypocoagulable state. 11 Rattlesnake venom is also reported to damage the endothelium and basement membrane of blood vessels and results in localized rhabdomyolysis. The gross and histologic findings in our warty pig cases are consistent with those described for rattlesnake envenomation in other species.…”