Specific treatment of cats with thrombocytopenia depends on the cause. If the animal is not bleeding and the platelet count is not seriously low, the underlying cause of the thrombocytopenia is usually treated without specifically attempting to treat the thrombocytopenia itself. If the specific cause of thrombocytopenia can be treated successfully, platelet numbers will increase quickly. The best approach is to treat the underlying disease responsible. If thrombocytopenia is severe and likely to result in bleeding, the following may be considered: Blood transfusion. It is difficult to increase the platelet count significantly with blood transfusion alone, and transfused platelets last only hours to days. Despite this, life-threatening bleeding may be treated with transfusion of whole blood, which contains all blood components including plasma and cells; packed red cells, which contain only red blood cells; or platelet-rich plasma, which contains only platelets and plasma.
If your cat is markedly anemic from blood loss, transfusion of whole blood or packed red blood cells may be necessary to provide red cells to carry oxygen to the tissues. Platelet-rich plasma is difficult to prepare and is not widely available in veterinary medicine.
Corticosteroids. Cortisone-like drugs such as prednisone often are used to inhibit destruction of the platelets by the immune system. Immune-mediated destruction of platelets is a common cause of severe thrombocytopenia, and corticosteroids often are used as soon as severe thrombocytopenia is identified.
Antibiotics, tetracyclines. These drugs are often used until results of specific tests for infectious disease are available. Many of the infectious agents that cause thrombocytopenia, such as the rickettsial agents that cause Rocky Mountain Spotted Fever and ehrlichiosis, are responsive to treatment with tetracycline.
Elimination of other drugs. If possible, any drugs your cat was receiving before developing thrombocytopenia will be discontinued because many drugs can cause thrombocytopenia.
Vincristine. This is a cancer chemotherapy drug that also can accelerate the release of platelets from the bone marrow where they are produced. If the bone marrow is functioning normally, vincristine may be administered to accelerate platelet release from the marrow.
Cyclophosphamide (Cytoxan) is another drug that may be used in cats with suspected immune-mediated thrombocytopenia, especially those cats that have not responded adequately to corticosteroids. This drug has strong immunosuppressive effects and also can have potentially serious adverse effects. It should be used only with close veterinary supervision.
Splenectomy. Removal of the spleen may be recommended in cats with immune-mediated thrombocytopenia that respond poorly to medical treatment. It may also be used in those cases in which sequestration of platelets is suspected, because the spleen is a major site of platelet destruction and sequestration. The spleen is submitted for microscopic examination by a veterinary pathologist after removal. The spleen should not be removed if the thrombocyotpenia is caused by an infectious agent.