GRH Haematology and Immunology

Interactive case-based discussion on diagnosing and managing common, and less-common types of canine and feline lymphoma.

How to manage a cytopenic patient

• Understand when to worry about cell counts; and which cell counts are most important
• Discuss investigation of a cytopenic case
• Describe a practical approach to febrile and afebrile neutropenia

Abnormal circulating cells? What now?

• Review biology of leukaemias and differentiation / overlap with lymphomas
• Overview of cytology of acute and chronic leukaemias
• Understand utility of flow cytometry to classify lymphocytosis

   In part one of this series, Carla Asorey Blazquez and Ferran Valls Sanchez of Dick White Referrals discussed the causes of anaemia in dogs. In this article they describe the logical steps to making a diagnosis.

Immune-mediated haemolytic anaemia occurs less commonly in cats than dogs. Young to middle-aged cats appear most commonly affected. In addition, it may be more difficult to diagnose for several reasons: jaundice is less commonly seen on clinical examination; spherocytosis is not reliable in cats, as their normal red blood cells are smaller and lack central pallor; cats are more prone to haemolysis from oxidative damage due to e.g. drugs or toxins (methimazole, paracetamol, garlic, onions), Heinz Body anaemia (diabetes mellitus) enzymopathies (pyruvate kinase deficiency); cat erythrocytes commonly form rouleaux, which can be misinterpreted as agglutination; IMHA may be non-regenerative, decreasing the index of suspicion of IMHA as the cause of anaemia. As with canine disease, primary IMHA must be differentiated from secondary IMHA. Recognised causes of secondary IMHA include infections (e.g. M. haemofelis, Feline Coronavirus, retrovirus infection, Babesia), inflammatory disease processes (e.g. pancreatitis, cholangiohepatitis) and drugs (e.g. propylthiouracil). There is no evidence that vaccination can act as a trigger for IMHA in cats, and the evidence for neoplasia acting as a trigger appears weak. Prednisolone forms the mainstay of therapy, with additional immunosuppressive drugs such as ciclosporin, chlorambucil and mycophenolate mofetil also having been used in conjunction with prednisolone.

Feline leukaemia virus (FeLV) is a retrovirus of domestic cats worldwide. Cats lacking strong FeLV-specific immunity and undergoing progressive infection commonly develop fatal FeLV-associated disease. Many aspects of FeLV infection pathogenesis have been elucidated, some during more recent years using molecular techniques. It is recommended that the FeLV status of every cat is known, since FeLV infection can influence the prognosis and clinical management of every sick cat. Knowledge of a cat’s FeLV status is of epidemiological importance to prevent further spread of the infection. The question is… how often are you testing for this important disease? Diagnosing FeLV infection remains challenging due to the different outcomes of infection, which can vary over time depending on the balance between the virus and the host’s immune system. Furthermore, testing for FeLV infection has become more refined over the years and now includes diagnostic assays for different viral and immunological parameters. The question is… which test is best and when? This webinar presents recent knowledge on FeLV pathogenesis, key features to be determined in FeLV infection, and frequently used FeLV detection methods, and their characteristics and interpretation. This webinar is provided by BSAVA Education Partner IDEXX. A collection of IDEXX ‘topic of the month‘ webinars is available here.

  This month Simon Tappin, Editor of Companion, discusses diagnosis and treatment of canine immune-mediated haemolytic anaemia.