Canine immune-mediated thrombocytopenia

The aim of this article is to provide an up to date overview of this disease and highlight key aspects of nursing care and owner support. Immune-mediated thrombocytopenia (IMT) is the most common cause of a low platelet count seen in dogs. Destruction of the platelets occurs when immunoglobulins attach to the platelet surface, causing macrophages to respond and initiate phagocytosis (Harvey, 2011). Primary IMT is idiopathic and only diagnosed after the exclusion of the causes of secondary IMT and other causes of thrombocytopenia, such as bone marrow disorders. Secondary IMT can result from an infectious agent, such as viral, bacterial or parasitic organisms, neoplasia or a drug-induced aetiology, such as the use of sulpha-based antibiotics (Cummings and Rizzo, 2017). Blood transfusion may also induce IMT (Day and Kohn, 2012).

This is a common disease and occurs more frequently in dogs than cats. Signalment is strongly associated with Primary IMT (Day and Kohn, 2012). Documented breed pre-dispositions include; Cocker Spaniels (Figure 1), Miniature and Toy Poodles, Golden Retrievers, German Shepherds and Old English Sheep Dogs. Females are twice more likely to be affected than males (O'Marra et al, 2011). Age of onset reported in the literature ranges from <1–14 years, however, the majority of cases are reported with a median age between 4–8.1 years (Lewis and Meyers, 1996; O'Marra et al, 2011; Day and Kohn, 2012).