Low Platelets in Cats

What Are Low Platelets in Cats?

Platelets are small, round, or oval-shaped cells produced by the bone marrow that circulate in the bloodstream. They clump together to form a blood clot that stops bleeding when there are damaged blood vessels.

When a cat has a low platelet count (also known as thrombocytopenia), serious bleeding and bruising can occur if the cat suffers an injury. The bruises may vary in size and appear anywhere on the body.

Thrombocytopenia is rare in cats and is considered a medical emergency due to the potential for severe internal bleeding. This condition can be fatal if it isn’t treated quickly.

Possible causes of thrombocytopenia in cats include autoimmune diseases, infections, cancer, and toxicity.

Symptoms of Low Platelets in Cats

While thrombocytopenia can sometimes be asymptomatic initially, symptoms will later develop and may include:

• Bruising (ecchymosis)

• Uncontrollable bleeding from a wound

• Pinpoint red spots on the skin or gums (petechiae)

• Lethargy

• Collapse

• Pale pink or white gums

• Vomiting blood

• Bloody diarrhea

• Black, tarry stools

• Nosebleeds

• Difficulty breathing

• Fever

• Retinal hemorrhage

• Blood in the front chamber of the eye (hyphema)

Causes of Low Platelets in Cats

There are various possible causes for a low platelet count in cats. Here are a few of the common ones.

• Infectious diseases, such as:

  • Feline leukemia virus (FeLV)

  • Feline immunodeficiency virus (FIV)

  • Feline infectious peritonitis (FIP)

  • Feline distemper (panleukopenia virus)

  • Mycoplasmosis

  • Ehrlichiosis

  • Salmonellosis

  • Histoplasmosis

  • Toxoplasmosis

  • Heartworm disease 

  • Cytauxzoonosis

• Autoimmune disease—Immune-mediated thrombocytopenia

• Cancers—Lymphoma, leukemia, hemangiosarcoma

• Medications, such as: 

  • Carprofen

  • Trimethoprim-sulfa

  • Methimazole

  • Phenobarbital

  • Other chemotherapeutic medications

• Rodenticide (rat poison) toxicity

• Disseminated intravascular coagulation (DIC)—A blood-clotting disorder

All cats, regardless of breed, age, or gender, are equally at risk for developing thrombocytopenia.

How Veterinarians Diagnose Low Platelets in Cats

Veterinarians rely on several factors to diagnose this condition, including:

• Medical history—It is important to discuss with your veterinarian any symptoms that your cat is displaying at home, such as nosebleeds, collapse, or bruising of the skin.

• Physical exam—A veterinarian will examine your cat’s mouth for pale gums and red spots (petechiae) and look for bruising on the body, as well as wounds that continue to bleed.

  • A fever or heart murmur may also be found during an exam. Cats with a low platelet count can also appear to be healthy during a physical exam with no indications of having a bleeding disorder.

• Blood cell count—This blood test measures a cat’s platelet count as well as the counts of white and red blood cells.

• Blood smear—A manual platelet count can help determine if a cat’s platelets are low. This test also helps identify platelet clumping and can help confirm if a previous low platelet reading was false.

• Anti-platelet antibody test—This blood test screens for immune-mediated thrombocytopenia, a condition in which a cat’s immune system attacks and destroys its own platelets.    

• Coagulation tests—Blood clotting tests may be recommended to check for DIC, assess if a cat has a bleeding disorder, or may have ingested rodenticide.

• Bone marrow biopsy—A biopsy of the bone marrow can be analyzed to check for cancer, infectious agents, and other diseases that might prevent a cat’s ability to produce platelets.

Treatment of Low Platelets in Cats

Treatment depends on the underlying cause.

For example, if an infection is causing a low platelet count, then treating the infection should return the platelet count to normal.

Cats with immune-mediated thrombocytopenia are prescribed immunosuppressive medication like prednisolone. Some cats with this condition can be slowly tapered off medication completely, while others may require long-term use at the lowest effective dose.

For cats with low platelet counts due to cancer, treatment options may include surgery, radiation, and/or chemotherapy.

Cats with hemorrhaging or a severely low platelet count are typically hospitalized and given a platelet-rich plasma transfusion to restore their platelet count to normal.

Bloodwork is repeated every few weeks after a transfusion to recheck the platelet count to see if the level remains normal or decreases again over time. Medications to stimulate platelet production—such as vincristine and erythropoietin—may be prescribed. 

Recovery and Management of Low Platelets in Cats

Recovery depends on the underlying cause, the severity of the disease, and your cat’s response to treatment.

It’s ideal to keep a cat with a low platelet count indoors and minimize their activity level, as even a minor injury could lead to uncontrollable bleeding.

Monitor your cat’s skin regularly to make sure that any bruises are fading and new bruises are not forming. Also observe your cat’s food and water intake, energy level, and their urination and defecation to determine if they are normal or abnormal during their recovery. 

Some infectious diseases—such as ehrlichiosis and mycoplasmosis—are treatable in roughly four weeks. However, other causes of a low platelet count in cats—such as heartworm disease and feline leukemia—have no curable treatment option.

Immune-mediated disease will require frequent blood work to determine if immunosuppressive medications can be tapered off over time. Treatment for immune-mediated thrombocytopenia can take several months or may even be lifelong. 

Prevention of Low Platelets in Cats

Some causes for low platelets can be prevented. Here are some recommendations for protecting your cat:

1. Administer heartworm, flea, and tick prevention year-round to protect your cat against heartworms, ehrlichiosis, cytauxzoonosis, and mycoplasmosis.

2. Keep rodenticide far out of your cat’s reach or do not use it at all.

3. Keep your cat indoors to reduce their risk of infectious diseases.

4. Do not feed a raw diet to your cat, as this can increase the risk of salmonellosis and toxoplasmosis.

5. Keep your cat up to date on their feline leukemia and feline distemper vaccinations.

6. Report any adverse side effects to your veterinarian when giving oral medications to your cat.

7. If you’re getting a kitten from a breeder, choose a reputable breeder who ensures their breeding cats and kittens are negative for feline leukemia and feline immunodeficiency virus.  Also have your kitten tested for feline leukemia and feline immunodeficiency virus at your local veterinary hospital.

8. Have routine blood work done on your cat every six to 12 months for screening.

Some causes of a low platelet count are not preventable, such as immune-mediated thrombocytopenia and cancer.