Thrombocytopenia in Cats

By Ernest Ward, DVM; Updated by Amy Panning, DVM

What is thrombocytopenia?blood_cells_from_bone_2018-01

Thrombocytopenia is a term that refers to a decrease in the number of thrombocytes (also known as platelets) circulating in the blood.

What are platelets?

Platelets produced in the bone marrow. Platelets clump together to seal broken or leaking blood vessels and prevent blood loss. They are an important factor in the blood clotting mechanism, and thrombocytopenia can lead to spontaneous bleeding or bruising.

What causes thrombocytopenia?

Any severe or prolonged blood loss, increased internal destruction of platelets, or impaired bone marrow production can lead to acute (short-term) or chronic (long-term) deficiency of platelets.

What diseases or conditions are associated with thrombocytopenia?

"Many severe diseases have thrombocytopenia as one component of the condition."

Many severe diseases have thrombocytopenia as one component of the condition. For example, certain infections, neoplasia (cancer), immune system disorders, and pancreatitis can result in thrombocytopenia, as can drug therapies such as some anti-cancer treatments.

How common is thrombocytopenia?

Thrombocytopenia is quite common. Some surveys have shown as many as 1% of cats admitted to veterinary hospitals are platelet-deficient.

How is thrombocytopenia diagnosed?

This condition is easily diagnosed with a simple blood test. Platelet counts are usually performed as part of a CBC or complete blood count.

"Additional diagnostic tests are used to investigate the underlying causes of the problem."

Platelet counts of less than 20,000 to 30,000 per microliter of blood (normal platelet counts are 175,000-500,000) make spontaneous hemorrhage likely. Additional diagnostic tests are used to investigate the underlying causes of the problem. These may include additional blood tests, X-rays, ultrasound, or bone marrow samples depending on the nature of the suspected underlying process.blood_cells_2017

What treatments are used?

If the blood loss has been acute or sudden, a blood transfusion may be required. Usually, other therapeutic treatments will be aimed at addressing the underlying causes of the problem.


Can there be bleeding disorders with normal numbers of platelets?

Yes, this can happen if platelet function is impaired. This can be a side effect of some drugs, including antibiotics. Cats can be affected by inherited platelet defects, such as Von Willebrand's Disease, although this disease is rare in cats. Another example is Chediak-Higashi syndrome, a condition identified by partial albinism (lightly colored iris of the eye), and seen in some lines of Persians and other breeds (see handout "Chediak-Higashi Syndrome in Cats" for more information). Diagnosis requires tests of platelet function. There are no specific treatments other than transfusions as needed.

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