Serum biochemical changes in cats with naturally acquired feline cytauxzoonosis

OBJECTIVE The geographical distribution of feline cytauxzoonosis is expanding in the US. Clinical signs of feline cytauxzoonosis, including lethargy, anorexia, and icterus, are similar to hepatic lipidosis and cholangiohepatitis. Hematologic and se-rum biochemical abnormality patterns may assist practitioners in prioritizing feline cytauxzoonosis as a differential diagnosis over hepatic lipidosis and cholangiohepatitis.SAMPLE Hematology and serum biochemical profiles of cats with naturally acquired feline cytauxzoonosis, hepatic lipidosis, or cholangiohepatitis.PROCEDURES Retrospective search and analysis of the Kansas State Veterinary Diagnostic Laboratory or Kansas State University Veterinary Health Center records between January 2007 and June 2018 for cats with cytauxzoonosis, hepatic lipi-dosis, or cholangiohepatitis.RESULTS Patients with acute feline cytauxzoonosis presented with frequent nonregenerative anemia (20/28 [71%]), leukope-nia (23/28 [82%]), thrombocytopenia (23/23 [100%]), hyperbilirubinemia (27/28 [97%]), hypoalbuminemia (26/28 [93%]), reduced (18/28 [64%]) or low normal (10/28 [36%]) serum ALP activity, and hyponatremia (23/28 [82%]). Reduced ALP activity was unique to cats with feline cytauxzoonosis relative to hepatic lipidosis and cholangiohepa-titis. No correlation between the severity of anemia and the magnitude of hyperbilirubinemia was identified in feline cytauxzoonosis patients.CLINICAL RELEVANCE The combination of nonregenerative anemia, leukopenia, thrombocytopenia, hyperbilirubinemia, and reduced serum ALP activity in icteric cats may increase the clinical suspicion, but is not pathognomonic, for acute feline cytauxzoonosis. Hematologic and serum biochemical abnormalities of naturally acquired feline cytauxzoonosis are like those reported with feline bacterial sepsis. Blood smear evaluation for intraerythrocytic Cytauxzoon felis piroplasms, tissue aspirates for schizont-laden macrophages, and/or molecular testing are required to diagnose feline cytauxzoonosis.