Platelets are small, cell‑like fragments that are made in the bone marrow and start the blood-clotting process. When bleeding occurs, platelets gather at the site and clump together to form an initial plug that slows or stops blood flow. They also release substances needed to complete clotting.
Platelet disorders can result from too few or too many platelets, or from platelets that do not work correctly. When platelet numbers drop very low, the risk of bleeding increases. Decreased platelet production can be caused by drugs, toxins, or bone marrow disease. Platelets can also be destroyed inappropriately in the bloodstream by the cat’s own immune system.
Conditions that use up large numbers of platelets (such as heavy bleeding or severe clotting disorders) can decrease platelet counts. Platelets are found normally in the spleen. An enlarged spleen can trap many platelets, causing the number of platelets in the blood to decrease.
An abnormally high platelet count is rare, and the cause is often unknown. It could be related to bone marrow disease or to long‑term blood loss caused by iron deficiency (because iron is required for normal red blood cell production).
Some disorders, such as von Willebrand disease, affect how platelets function rather than how many platelets there are. Other platelet function problems are rare.
Platelet dysfunction in animals is a possible side effect of aspirin. You should not give your cat aspirin—or any other drug—unless it is prescribed by your veterinarian.
