heart and blood (cardiovascular system): anemia

The Classic Comprehensive Handbook of Cat Care



Anemia is a common sign of illness in cats. Anemia occurs whenever a fewer than normal number of red blood cells is circulating in a cat’s bloodstream. It has many causes. A borderline degree of anemia may only be recognized by your veterinarian with the help of a complete blood cell count (CBC) or other laboratory tests.


More pronounced anemia causes other signs that you may be able to recognize at home. Pale-colored mucous membranes (look at your cat’s gums, tongue, roof of the mouth, and conjunctiva), decreased activity, and decreased appetite usually indicate anemia in cats. The skin that covers the nose and lines the ears may also become paler. An unusual accompanying sign seen in many anemic cats is an appetite for abnormal foodstuffs; many are seen to lick sidewalks or earthenware pots; others consume kitty litter. When anemia becomes very pronounced, pale mucous membranes become white, an abnormal shh sound may be heard in the heartbeat (a heart murmur), complete loss of appetite usually occurs, and any physical activity may lead to complete collapse and rapid, strained breathing. Also loss of bladder and bowel control is often seen. Anemia left untreated in these stages almost invariably becomes fatal within a few days or hours.

If you recognize signs of anemia in your cat, seek the help of a good veterinarian. Discovery of the anemia is only the first step; good treatment directed at the cause of the low red blood count requires thorough investigation. Rational therapy can only be applied when the specific disease producing the anemia is identified. Repeated blood counts and other more refined diagnostic tests, including measures of organ function (e.g., liver and kidney function tests) and bone marrow biopsy (removal of a sample of bone marrow for examination) are frequently necessary when treating an anemic cat. Patience and cooperation on your part are important assets if this serious problem arises.


The causes of anemia fall into three basic categories: anemia due to blood loss, anemia due to increased destruction of red blood cells, and anemia due to decreased production of new red blood cells. Blood loss most often follows trauma, such as that which occurs when a cat is hit by a car or falls from a height. In cases of blood loss due to trauma, other evidence of injury is often present.


Increased destruction of red blood cells usually accompanies Haemobartonella felis infection also known as feline infectious anemia (haemobartonellosis). This microscopic rickettsial organism attaches to the surface of the red blood cells causing them to be identified as abnormal and removed from the circulatory system. The organism responsible for this disease may be transmitted from cat to cat during fights, or through the uterus before birth. Blood-sucking external parasites such as fleas, lice, and ticks may also be responsible for its spread.

Carrier cats may be infected without showing signs of disease, and the exact combination of factors necessary for Haemobartonella to produce significant anemia is not yet fully understood. There are no preventive vaccines or drugs available for control of infectious anemia. The best prevention is to limit your cat’s exposure to other cats. The task of diagnosis and treatment requires the help of a veterinarian. The infectious anemia organism is often present accompanying other causes of anemia such as feline leukemia virus infection. In many of these instances treatment fails since antibiotic therapy directed at Haemobartonella may not help correct other more significant causes.

The failure to produce enough red blood cells is the more common cause of anemia in cats. This type of anemia is called bone marrow depression, but identifying an anemia as such is only a small part of the total picture. Cats have a very sensitive bone marrow, and almost any chronic disease can cause bone marrow depression and resulting anemia. Anemia due to bone marrow depression accompanies disease processes as diverse as bacterial infection following fighting wounds, kidney failure, panleukopenia, nutritional deficiencies, leukemia, lymphosarcoma, and feline immunosuppressive virus infection. Some causes are simple to diagnose and easy to treat; others are difficult to diagnose and sometimes impossible to treat successfully. In many instances the true problem emerges only after time passes and initial treatments do not succeed.

Treatment of anemia varies, of course, depending on its cause. Drugs commonly employed are antibiotics and vitamin-mineral supplements.

Bone marrow stimulants and blood transfusions are sometimes necessary as well. Home nursing care is very important. In addition to administering drugs as directed, you will need to provide a balanced diet and a warm, unstressful environment.