OD: Immune mediated haemolytic anaemia in dogs and cats (Vanessa McClure)
Immune-mediated haemolytic anaemia (IMHA) is one of the most common immune-mediated hematologic disorders in dogs. It can also occur in cats but is less common in this species. The disease is caused by immune-mediated destruction of red blood cells and is associated with considerable morbidity and mortality. A prompt diagnosis of IMHA is critical so that appropriate treatment can be started, but there is no single test that is definitively diagnostic for IMHA. The diagnosis is supported by the presence of haemolytic anaemia in a young adult or middle aged dog of a predisposed breed, (in which all other underlying cause of anaemia have been eliminate), the presence of spherocytes, RBC agglutination, positive results from a Coombs’ test, and an appropriate response to immunosuppressive treatment. Unfortunately, these tests do not differentiate spontaneous IMHA (primary IMHA) from IMHA caused by diseases or other trigger factors (secondary IMHA). Exclusion of secondary IMHA can be only be achieved by ruling out all the other possible causes of haemolytic anaemia such as an underlying infection, toxin exposure, and neoplasia. This will involve extensive testing using imaging and various other diagnostic tools.
The recommended treatment for IMHA is with immunosuppressive and antithrombotic drugs. Immunosuppression is usually accomplished with glucocorticoids, with the addition of a second immunosuppressive agent, if need. A second component of treatment of IMHA is the inhibition of thrombus formation using various antithrombotic drugs and regimes.
Recently, The American College of Veterinary Internal Medicine has published 2 consensus Statements, one on the diagnosis and the other on the treatment of IMHA.
My presentation will focus on these 2 documents and attempt to give you an update on the pathophysiology, diagnosis and treatment of this common immune-mediated hematologic disorders.