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Immune-mediated Decreased Platelets (Thrombocytopenia)

What is immune-mediated thrombocytopenia?

Platelets (also known as thrombocytes) are normal cellular bodies produced by the bone marrow. They circulate in the blood and are used as "tiny plugs" to stop bleeding. Immune-mediated thrombocytopenia occurs when the immune system destroys the body's own platelets. If enough platelets are destroyed, severe bleeding can occur in any organ system.

What causes immune-mediated thrombocytopenia?

The cause of immune-mediated thrombocytopenia is unknown. Cocker spaniels, Old English sheepdogs, poodles, and German shepherd dogs are more likely to develop this condition. Immune-mediated thrombocytopenia is rare in cats.

What are the signs of immune-mediated thrombocytopenia?

The signs of immune-mediated thrombocytopenia are related to abnormal bleeding. The pet may have bruising or tiny, pinpoint reddish areas caused by bleeding (petechia). Bleeding or hemorrhage (severe bleeding) can occur anywhere in the pet's body. Bleeding may be seen in the skin or gums and tongue (mucous membranes). The pet may have nosebleeds, vomit blood, or may have blood in the stool or urine. The pet may bleed more than expected following a small injury or surgery. The bleeding may lead to lethargy and weakness, and finally to collapse.

How is immune-mediated thrombocytopenia diagnosed?

Immune-mediated thrombocytopenia is diagnosed mainly upon physical examination and through various blood tests. The veterinarian will examine the pet and assess the severity of the bleeding. Complete blood counts (CBCs), platelet counts, and blood clotting profiles can indicate the severity of the platelet loss. The veterinarian will want to differentiate immune-mediated thrombocytopenia from other causes of thrombocytopenia. Cats may be tested for feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) as these viruses can cause thrombocytopenia. Infections, such as Rocky Mountain spotted fever, can cause thrombocytopenia in dogs. Cancer, drugs, and other immune-mediated diseases (such as lupus) also can cause thrombocytopenia; therefore, the pet will be evaluated for any suspected conditions.

Bone-marrow aspiration or biopsy (removal and examination of tissue, cells, or fluids) may be done to make sure that the thrombocytopenia is not caused by a low production of platelets.

How is immune-mediated thrombocytopenia treated?

The treatment for immune-mediated thrombocytopenia will be determined by the severity of the clinical signs and the actual platelet count. Steroids are administered until improvement in the platelet count is seen. If the low platelet count is unresponsive to steroids, other medications (such as chemotherapy) can be added. If the pet is hemorrhaging, it will receive emergency treatment. Blood transfusions are given if the thrombocytopenia is severe. When the pet has been stabilized, it can be cared for at home. Steroids, especially when used long-term, can cause side effects, so the pet will need to be seen regularly by the veterinarian for follow-up evaluations.

What is the prognosis for animals with immune-mediated thrombocytopenia?

The prognosis (outcome) for animals with immune-mediated thrombocytopenia is guarded. If the pet responds well to steroid therapy, the platelet count generally increases over several days and the prognosis is improved. If the platelet destruction is severe and cannot be improved quickly by treatment, the animal may die. In one study, approximately 25% of affected animals died or were euthanized. Of the pets that survived, 50% recovered and 50% had chronic disease that recurred months to years later.

Other Criteria:

Breed Predilection :

Cocker spaniel, poodle, Old English sheepdog, and, possibly, German shepherd

No known breed predilection in cats

Mean Age and Range :

Mean age in dogs, 6-7 years, Age range in dogs, 7 months to 14 years

Predominant Sex :

More common in female dogs

Historical Findings :

The majority of the information in this page is has been taken from VetMedCenter.com. For further information about this useful source of informtion follow the link or look, on the internet, at www.vetmedcenter.com.