Canine immune-mediated haemolytic anaemia part 1: presentation, diagnosis and treatment

Immune-mediated haemolytic anaemia (IMHA) is an autoimmune disease in which red blood cells are targeted by antibodies, leading to haemolysis. This may occur either within the vascular system, or extravascularly within the liver or spleen. In primary IMHA, no underlying cause is determined and normal red blood cells are targeted by antibodies. While primary IMHA is more common, secondary IMHA can also occur, where antibodies target red blood cells that have been altered by drugs, neoplasia, parasites or infectious diseases (McCullough 2003; Smith and Tappin, 2012).

IMHA is the most common reason for haemolytic anaemia in canine patients, however it is uncommon in cats (Woolcock and Scott-Moncrieff, 2019). Breeds including Springer Spaniels, Cocker Spaniels, Old English Sheepdogs, Collies and Poodles have been shown to be predisposed to IMHA (Smith and Tappin, 2012). The age of onset may range between 1–13 years, with a median age of 6 years (Smith and Tappin, 2012). Females are reportedly over represented (Garcia and South-Bodiford, 2012).