Successful management of acute bilirubin encephalopathy in a dog with immune-mediated hemolytic anemia using therapeutic plasma exchange.

Objective: To describe the successful management of acute bilirubin encephalopathy in a dog with immune-mediated hemolytic anemia (IMHA) treated with therapeutic plasma exchange (TPE) in conjunction with conventional medical management.

Case Summary: A 6-year-old neutered male Australian Cattle Dog diagnosed with IMHA developed severe hyperbilirubinemia and stupor within the first 48 hours of implementing immunosuppressive therapy consisting of corticosteroids and mycophenolate. The patient received 4 blood transfusions during this period, but remained severely anemic PCV (18%) and experienced a subsequent increase in total bilirubin from 78 µmol/L (4.6 mg/dL) to a peak value of 1,563 µmol/L (91.4 mg/dL). The patient's neurological status rapidly deteriorated, resulting in lateral recumbency, vertical nystagmus, extensor rigidity, and stuporous mentation. Over the next 3 days, TPE was provided once every 24 hours, decreasing serum bilirubin, immunoglobulin G (IgG), and immunoglobulin M (IgM). The patient's red blood cell (RBC) transfusion requirements decreased immediately, requiring only 1 transfusion over the next 7 days that was required due to procedure-associated blood loss. Gradual neurological improvement was noted as serum bilirubin decreased. A brain magnetic resonance imaging (MRI) did not reveal any structural abnormalities and the patient was discharged after 11 days of hospitalization. Following discharge, the patient had complete remission of IMHA without any residual neurological deficits. Therapeutic plasma exchange played an integral role in case management and was successful in reducing bilirubin, IgG, and IgM.

New Or Unique Information Provided: Bilirubin encephalopathy has been rarely reported in small animal medicine and cases have been limited to postmortem documentation. This is the first suspected case of acute bilirubin encephalopathy in a dog that survived and describes the clinical course of disease. The kinetics of serum bilirubin, IgG, and IgM concentrations before and after TPE and throughout the hospitalization period are also described.