Multiple splenic infarctions in a dog with immune-mediated hemolytic anemia: therapeutic implications

Background: Splenic infarction (SI) is a rare clinical entity seldom encountered in veterinary medicine. Its most frequent causes include thromboembolic status, splenomegaly, and cardiac disease. Although thrombotic elements from the circulation provide the most common context for thromboembolic SIs, immune-mediated hemolytic anemia (IMHA) has not been reported as an underlying disease in canine SI. Case description: A 2-year-old, female spayed Dachshund, was referred with vomiting, hematochezia, and brown colored urine over the preceding 4 days. Physical examination revealed abnormalities including generalized weakness, jaundice, and splenomegaly; blood work showed pancytopenia and hyperbilirubinemia. Erythrocyte agglutination, polychromasia, and spherocytes on a peripheral blood smear were observed and IMHA concurrent with thrombocytopenia was diagnosed. Findings/treatment and outcome: Although erythrocyte agglutination and leukopenia disappeared after treatment, anemia and thrombocytopenia were unresponsive to oral immunosuppressive drugs and repeated transfusions. Further abdominal ultrasound identified an occlusive splenic vein thrombus. Splenic histopathology found marked multifocal to coalescing necrosis, and hemorrhage consistent with multiple SI. Symptoms resolved following splenectomy combined with 1 month of immunosuppressive medication, and the dog was healthy on follow-up evaluation after 2 years. Conclusion: Immune-mediated hemolytic anemia is an incompletely characterized cause of SI. This report establishes a potential and novel causal role for IMHA in canine SI. We believe it to be the first case report of SI in a dog with refractory IMHA and thrombocytopenia, successfully managed by splenectomy combined with short-term immunosuppressive therapy.