Anticoagulant rodenticide screening in dogs: 123 cases (1996-2003)

Objective-To identify dogs with anticoagulant rodenticide (AR) screens submitted, determine whether detected concentrations of the anticoagulants correlated with severity of clinical signs for dogs with positive results on AR screens, and identify the most common disease processes present and the prognosis for those with negative AR screens. Design-Retrospective case series. Animals-123 dogs. Procedures-History, signalment, clinical signs, physical examination findings, PCV, total solids concentration, prothrombin time, activated partial thromboplastin time, platelet count, AR concentrations, duration of hospitalization, blood products administered, final diagnosis, and outcome were recorded from medical records of dogs that underwent AR toxicology screenings. Results-75 of 123 (60.9%) dogs tested positive for AR. Dogs tested positive for brodifacoum, diphacinone (also called diphenadione), and chlorophacinone. Dogs with positive AR screenings weighed significantly less, received significantly more fresh frozen plasma, had significantly longer initial prothrombin time, and were significantly more likely to survive, compared with those with negative screens. Anticoagulant rodenticide concentrations ranged from trace amounts to 1,120 parts per billion and were not correlated with any recorded parameter. The most common conditions diagnosed in the 48 dogs with negative screens included neoplasia in 15 (31.3%), immune-mediated disease in 7 (14.6%), and gastrointestinal bleeding in 5 (10.4%) dogs. Conclusions and Clinical Relevance-AR concentrations were not correlated with severity of clinical signs or the degree of prolongation of coagulation times in this series of patients. Patients with severe coagulopathies but negative results of AR screening had a poor prognosis, with neoplasia as the most common diagnosis. Anticoagulant rodenticide intoxication had the best prognosis, with a survival rate of 98.7% in this study.