Retrospective Study on 33 Cases of Canine Primary IMHA: Clinico-Pathological Features, Follow up and Prognostic Factors

Primary immune-mediated hemolytic anemia (pIMHA) is the most common immune-hematological disease in dogs, yet it still represents a prognostic and therapeutic challenge for many veterinarians. So far, only a limited number of prognostic indicators and outcome scores are accepted consistently. Influence of treatments initiated by referring veterinarians on clinico-pathological features, disease severity, follow-up, and survival time were investigated from time of presentation (T0) to our referral center up to 4 months post presentation. CHAOS and Tokyo severity scores were applied to all cases and compared with the disease outcome. Furthermore, several clinico-pathological signs were studied as prognostic factors at time of discharge from the Veterinary Hospital (TD), at 30 days and 120 days after discharge. Thirty-three cases of pIMHA (according to standard clinical and clinico-pathological criteria) collected between February 2010– 2016 were included. Data regarding history, blood and urine laboratory tests, and immunosuppressive treatments was collected. Patients were divided into two groups (16 patients previously treated by the referring vets, group A, and 17 untreated, group B) and statistically compared. In group A platelet count (P = 0.002) and serum concentrations of alkaline phosphatase (P = 0.010) were significantly higher than group B at T0. In group B serum concentrations of total protein (P = 0.025), globulins (P = 0.002), C-reactive protein (P = 0.003), and lactate dehydrogenase (P = 0.028), and urinary parameters as pigmenturia (P = 0.0003) and bilirubinuria (P = 0.041) were significantly higher than group A at T0 (Mann-Whitney test). CHAOS severity score was more predictive of outcome than Tokyo severity score at 30 and 120 days (Odd Ratio, OR, respectively 15.1 and 10.7). In addition, a few clinico-pathological signs were statistically related with a worse prognosis (OR): urea concentration (>55 mg/ dL) at TD, hyperbilirubinemia (>1.5 mg/dL) and number of nucleated RBCs (≥30/100 WBC) at T30 and T120, thrombocytopenia (<150 9 109/L) at TD, T30 and T120. Group B dogs had higher mortality rate (47%) than group A dogs (13%) after 2 weeks from T0 (P > 0.05, Kaplan–Meier curve). In conclusion, previous immunosuppressive treatments by referring veterinarians may weaken the clinician’s ability to properly assess patient’s prognosis. This study confirmed some literature information regarding diagnosis, prognosis and survival times of dogs suffering of IMHA and it adds additional prognostic factors such as urea concentration, hyperbilirubinemia, circulating nucleated RBCs and thrombocytopenia. Disclosures: No disclosures to report.