Demographics of canine immune-mediated haemolytic anaemia in the Southeastern United States

Detailed examination of the records of 57 dogs referred to our clinic with the diagnosis of immunemediated haemolytic anaemia was accomplished. Only untreated dogs or dogs who had only received supportive therapy were included in the study group comprising 30 male dogs and 27 female dogs. Age distribution followed the general age distribution of our patient population. There was no within-breed sex or age predilection. The youngest dog was 11 months of age and the oldest dog was 13 years of age. Overall mortality rate among the study population was 51% (29 dogs). Certain canine breeds were over-represented in this study and these same breeds had high mortality rates. Included were 11 cocker spaniels (19%; 82% mortality rate, 9 of 11 dogs), nine dogs with terrier in their name (16%; 78% mortality rate, 7 of 9 dogs), six German shepherds (11%; 50% mortality rate, 3 of 6 dogs), five doberman pinschers (9%; 60% mortality rate, 3 of 5 dogs), and five miniature schnauzers (9%; 60% mortality rate, 3 of 5 dogs). Immune-mediated haemolytic anaemia was considered secondary to hepatic disease in 16 dogs (28%), septicaemia in 10 dogs (18%) and neoplasia in six dogs (11%), i.e. signs and data supporting these processes were reported to have preceded anaemia. A total of 29 dogs (51%) also had thrombocytopenia (platelet counts less than 60000 cells/µl), eight (14%) dogs had major venous thrombosis, eight (14%) dogs had associated disseminated intravascular coagulation, and 24 (42%) of the dogs had evidence of renal disease — proteinuria and cylinduria. About 35% (20 dogs) of the patients were treated from June to August, and 63% (36 dogs) of the patients were direct antiglobulin positive (immunoglobulin G with or without complement). A variety of red cell morphological changes were observed including stomatocytes, bowl forms, knizocytes, schistocytes and spherocytes. Spherocytes were observed in 11 dogs (19%). Absolute reticulocytosis was observed in 26 dogs (46%). A variety of treatment combinations including glucocorticoids, azathioprine, cyclophosphamide, anabolic steroids, heparin, intravenous human gamma globulin, and blood component therapy were used without identifiable success associated with any given protocol.