• Anemia in cats has many possible causes, and it can range in severity from mild to severe.  Severe anemia is life threatening and requires immediate veterinary care.
  • Anemia results from a loss or destruction of red blood cells or from a failure of the body to produce enough red blood cells.  Red blood cells carry oxygen throughout the body; therefore, anemia can cause lethargy (tiredness) and exercise intolerance (difficulty exercising).
  • Anemia is not contagious. However, anemia can be caused by infectious diseases that can be transmitted from cat to cat either through fighting and bites or sharing water and food bowls.
  • Immediate treatment for severe anemia may require a blood transfusion to replace lost red blood cells.  Prognosis and treatment are based on the cause of the anemia.
  • Certain causes of anemia may be preventable.  For example, to reduce the risk of infectious diseases, keep your cat indoors.  If your cat does go outdoors, ask your veterinarian what vaccines are recommended.

What Is Anemia?

Anemia develops when the number of red blood cells in the bloodstream is reduced.  Red blood cells carry oxygen throughout the body.

There are many different causes and types of anemia.  Anemia may result from blood loss, the destruction of red blood cells within the body, or the inability of the body to produce enough red blood cells.  The type of anemia depends on its cause.  For instance, a severe injury that causes bleeding externally or internally can result in blood loss that causes anemia.  Other causes of anemia include:

  • Infection with a virus, such as feline leukemia virus (FeLV) or feline immunodeficiency virus (FIV), or with a parasite (Mycoplasma haemophilus)
  • Blood loss from severe flea infestations (especially in kittens)
  • Immune-mediated disease (a condition in which the body’s immune system attacks its own red blood cells)
  • Bleeding into the gastrointestinal tract as a result of disease or severe inflammation
  • Reaction to certain drugs
  • Exposure to certain toxins
  • Cancer (may decrease red blood cell production or lead to bleeding from a tumor)
  • Kidney disease (may lead to a decrease in red blood cell production)

Signs of Anemia in Cats

  • Lethargy (tiredness)
  • Decreased appetite
  • Exercise intolerance (difficulty exercising)
  • Pale mucous membranes (gums, inner eyelids)

How Is Anemia Diagnosed and Treated?

A simple blood test can diagnose anemia.  Most veterinarians can perform a quick blood test called a packed cell volume (PCV) in the hospital.  The PCV indicates the volume of red blood cells in the bloodstream.  If your cat’s PCV is lower than the normal range, anemia is diagnosed.  Your veterinarian will also take a complete history and consider physical exam findings, including whether your cat has a fever.

Other blood tests can offer more detailed information regarding the anemia, such as whether the body is producing new red blood cells to replace the lost or destroyed red blood cells.  Another test looks at the structure of the red blood cells to help determine suspected causes of the anemia.  A CBC (complete blood cell count) is also an important test when evaluating a cat for anemia.  This test looks at red blood cells, white blood cells (which fight infection and contribute to inflammation), and platelets (which help with proper blood clotting.)

It is extremely important to identify the cause of the anemia so that proper and effective treatment may be given.  Therefore, your veterinarian may recommend other diagnostic tests, including blood tests to check liver and kidney function and to determine exposure to FeLV, FIV, Mycoplasma haemophilus, and certain diseases.  Taking radiographs (x-rays) of the chest and abdomen can help check for tumors that may be bleeding, and an ultrasound of the abdomen can help check for fluid (blood), signs of cancer, or liver, kidney, intestinal, or pancreatic disease.

In cases of anemia resulting from sudden loss of a large amount of blood, or severe anemia from blood loss over time, a blood transfusion may be recommended (or required) for survival.  Severe anemia results in a significantly reduced ability of the blood to deliver oxygen throughout the body and, most importantly, to vital organs such as the brain.  Therefore, a blood transfusion is necessary to help deliver oxygen and nutrients to major organs and other parts of the body.  Occasionally, multiple transfusions are required before the cat’s body can produce enough red blood cells on its own.

Other treatments for anemia are determined based on the diagnosis of the underlying cause.

How Can I Prevent Anemia?

Prevention of certain causes of anemia may be aided by basic care and maintenance.  You can decrease your cat’s risk of exposure to FeLV and FIV by keeping him or her indoors and away from stray or unknown cats.  If your cat does go outside, ask your veterinarian what vaccines are recommended.  Avoid leaving cat food outside, as this often attracts other cats and wildlife that may transmit disease.  If your cat lives inside only, ask your veterinarian what he or she recommends regarding the FeLV vaccine.

You can reduce the risk of diseases transmitted by fleas with the regular use of veterinarian-approved flea and tick control products.  Discuss with your veterinarian the best plan for flea and tick prevention.  Flea prevention is very important for indoor cats as well.

Monitor your cat’s daily habits, including food and water intake and litterbox use.  If you notice changes such as a marked increase in water consumption or urination, unexpected weight loss, or blood in the stool or urine, have your cat evaluated by your veterinarian and discuss the changes you have observed.  These signs may be indicators of diseases that may lead to anemia or other problems.