Thrombocytopenia (decreased platelet count)

Thrombocytopenia (a decrease in the number of platelets) is a life-threatening condition. The success of treatment depends on the primary disease and response to treatment.

©Roger Powell

Thrombocytopenia is the term used when a patient does not have enough platelets in the blood. Platelets (also called thrombocytes) are cell fragments that are necessary for forming blood clots and help in repairing damaged blood vessels. Their numbers can be low if not enough are being made in the bone marrow or if too many are being used or destroyed by the body.

If platelet numbers are too low, uncontrolled bleeding can occur, and if treatment is unsuccessful, the patient will die from overwhelming blood loss.

The signs of thrombocytopenia are:

• Small bloody spots seen on the skin or gums
• Bleeding from the nose
• Blood in vomit, stool, or urine
• Excessive bleeding from a wound
• Pale gums
• Lethargy, weakness

Causes of thrombocytopenia include blood loss, immune system disorders, clotting disorders, cancer, and infectious diseases such as Rocky Mountain spotted fever and feline leukemia virus.

Thrombocytopenia is diagnosed based on history, clinical signs, physical examination findings, and laboratory tests. A platelet count is included in a complete blood count (CBC). Other tests may be performed to determine what is causing the low platelet numbers. These may include a blood chemistry panel, urinalysis, radiography (x-rays), ultrasound, tests for immune diseases, tests for infectious disease, and bone marrow sampling.

Thrombocytopenia needs to be treated as soon as it is recognized. As many of the illnesses that cause thrombocytopenia are not obvious right away, your veterinarian may choose to start treatment for the most common causes before knowing the exact one. Initial treatments may include blood or plasma transfusions, steroids, and antibiotics. As the diagnosis becomes clear, your veterinarian may customize treatment. Some patients may need to be medicated for months to years until their platelet numbers stabilize. Follow-up care for these patients consists of frequent physical examinations and platelet counts. Medications may be slowly discontinued after platelet numbers have been in the normal range for some time; however, relapses occur in about 50% of cases, and some pets may not respond to treatment.

There is no known way to prevent thrombocytopenia, but the use of the feline leukemia vaccine (in cats) and a solid tick prevention strategy may help in the prevention of infectious diseases that can cause thrombocytopenia. Avoiding the original cause may minimize relapses.