Signs, Causes, and Treatment of Anemia in Cats

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by Carol McCarthy

If you notice your cat is more lethargic than usual, is breathing rapidly even when lying still, and seems uninterested in her favorite cat treats, she might be suffering from anemia. While these symptoms can indicate a number of health issues, they might be the first signs of this blood disorder that a pet parent notices.

Anemia is a deficiency in red blood cells, which are needed to carry oxygen throughout the body and keep organs functioning properly. Red blood cells have an average life span of about 65 days, so the body needs to continually keep producing more, explains Dr. Cathy Lund of City Kitty, a feline-only veterinary practice in Providence, RI.

Cats can get two different types of anemia, regenerative and nonregenerative, and the causes for each are varied. Regardless of type or cause, your cat will feel lousy if she is anemic, and her overall health is at risk, says Dr. Maureen Carroll, who practices internal medicine at the Massachusetts Society for the Prevention of Cruelty to Animals-Angell Animal Medical Center.

So how does a cat get anemia, and what do you do about it? The doctors explain.

What is Regenerative Anemia?

This is the result of sudden or acute blood loss, whether from an injury, a parasite, infection, or an illness such as cancer. Basically, the body suffers an injury that results in a large loss of blood or suffers from a condition that destroys red blood cells, Dr. Lund says.

What is Non-Regenerative Anemia?

This type of anemia is the result of chronic disease, such as kidney failure, Dr. Carroll says. Kidneys produce a hormone that aids in the production of red blood cells, but when kidneys are not working properly, those cells are not replaced as quickly as the cat’s body is using them, and anemia results.

Which Form of Anemia is More Common?

“Regenerative anemia tends to be more common in younger cats, and non-regenerative anemia is more common with older cats,” Dr. Carroll says. “In younger cats we tend to see issues such as flea infestation and blood parasites as a key driver of anemia. In older cats, the causes tend to shift toward chronic disease of any organ system—such as renal (kidney) disease.”

What is the Most Common Underlying Cause of Anemia in Cats?

The most common underlying cause of anemia is chronic disease, as anemia is a typical side effect of age-related health conditions, Dr. Lund says. “The system gets turned off. With kidney disease, for example, you are losing blood but you can’t make more.”

What Are Some Other Causes of Anemia in Cats?

Blood loss from fleas/ticks and parasites or an injury can cause regenerative anemia. Kittens can be at particular risk.

“A lot of fleas on a tiny kitten can suck that kitten dry. It’s sort of like the ultimate vampire routine,” Dr. Lund says. That type of anemia is strictly from blood loss; the blood cells are not being damaged, she notes.

With nonregenerative anemia, kidney disease, auto-immune diseases and bone marrow problems—including leukemia—are at the root of the problem, Dr. Carroll says.

What Are the Primary Symptoms of Anemia in Cats?

Lethargy, loss of appetite, shortness of breath, and rapid breathing are common symptoms, but typically they are not evident until the anemia has become severe—or if there is a severe systemic disease that has led to the anemia, Dr. Carroll says.

More acute cases, as from an injury or flea infestation, are easier to spot. Slower blood loss from a chronic illness can be more subtle, as the body adjusts to lower red blood cell counts over time. Really observant pet parents might notice that their cats’ gums are pale, almost white compared to a healthy pink, Dr. Lund says. And if you are visiting your vet, she or he might hear a heart murmur.

Can Anemia Be Fatal for a Cat?

In severe cases anemia can be fatal, the doctors say. Anemia, as part of feline leukemia, is eventually always fatal. Acute cases of anemia, say from sudden and severe blood loss due to a traumatic injury, also can be fatal.

How is Anemia Diagnosed?

Your veterinarian will take a sample of your cat’s blood and run several tests as part of a “complete blood count.” This measures the amount of red and white blood cells, the hematocrit level—the ratio of red blood cells to white blood cells—as well as the reticulocyte count, or the number of “immature” red blood cells present in your cat’s blood. A normal red blood cell count for a cat is 35. At half that, your cat would be seriously ill and at risk of death.

How is Anemia Treated in Cats?

In cases of severe anemia, from either an acute or chronic cause, your veterinarian might give your cat a transfusion of blood from a donor cat.

“A combination of diet and medications also can be effective in treating anemia, depending on the underlying cause,” Dr. Carroll says. For example, there are cat foods designed specifically for animals with kidney impairment to help their kidneys work more efficiently for a longer time with less stress on the organs.

Determining the underlying cause of the anemia is the key to finding the right treatment. If your cat has regenerative anemia from a parasite, then prescription dewormer for cats is needed. If a flea infestation is the problem, you and your vet must address that, perhaps with prescription flea and tick for cats.

If your cat has kidney disease, she can be put on long-term hormone treatments that help the kidneys produce red blood cells. “With kidney disease, you are trying to keep the blood count in the 20s for quality of life,” Dr. Lund says.

If an auto-immune disease, in which the body attacks itself, is the cause of the anemia, your vet can prescribe steroid treatment or other immunomodulatory drugs.

How Can Anemia Be Prevented?

“For cats, the most important tool at our disposal is simply to keep them safe. Keep them indoors and keep them clear of fleas and gastro-intestinal parasites,” Dr. Carroll says.

Year-round flea and trick control is particularly important, even for indoor cats, and preventive treatment should be used year-round. The best line of defense for anemia from age-related conditions or chronic illness is to take your cat in for regular wellness exams, where your vet can stay on top of potential disease risks.