Extreme leukemoid reaction in a dog with pyometra

Leukemoid reaction has been rarely encountered in dogs. This report describes a case of leukemoid reaction showing extremely elevated leukocyte count. A 10-year-old female Maltese dog was presented with purulent and bloody vaginal discharge. The CBC revealed severe leukemoid reaction (976 x 10⁹ cells/1, reference range 6 to 17 x 10⁹ cells/ 1) and mild non-regenerative anemia. On the blood smear, elevated leukocytes consist of numerous neutrophils and monocytes only. Radiographic and ultrasonographic examinations revealed generalized enlargement of the uterus, which was filled with a complex fluid. After ovariohysterectomy, Escherichia coli was isolated from the uterine fluid. To author's knowledge, it is the new record of extreme leukemoid reaction caused by local bacterial infection in dogs.