Anemia is a deficiency of circulating red blood cells.  These cells are responsible for the delivery of oxygen to body tissues and the symptoms associated with anemia are related to the lack of oxygen in tissues and the body’s physiologic adjustments to this decreased oxygen availability.  Anemia can result from the loss of red blood cells or diminished production of red blood cells in the bone marrow.  The severity of signs depends on the degree of anemia and whether the anemia is acute or chronic.

Common symptoms include: 

• Pale gums

• Weakness

• Exercise intolerance

• Rapid heart rate

• Pica (eating unusual substances)

• Depression

• Decreased appetite

• Cold intolerance

• Rapid respiratory rate

Identifying the cause of anemia is essential to diagnosis, therapy and prognosis. This process begins with a thorough medical history, physical examination and diagnostic testing. The medical history provides information about toxin exposure, trauma, and medications. The physical examination may reveal evidence of external parasites, signs of trauma, changes in abdominal organs, clues to infectious processes and other information that will contribute to the diagnosis.

Initial diagnostic testing:

1.   FeLV/FIV (a high percentage of anemic cats may have one or both of these viruses)

2.  CBC (answers important questions: how low is the red cell count, are the red cells abnormal,  are more red cells being made, are there blood parasites)

3.  Comprehensive metabolic profile (may reveal a disease that can cause anemia such as kidney disease)

If the initial testing does not identify the cause of the anemia, additional tests are needed:

1.      Histoplasma antigen testing (a fungal infection that can suppress the bone marrow)

2.      Bone marrow aspirate (with cytology and FELV testing)    

Once testing is complete the most likely cause(s) of the anemia can be identified. Some of the more common causes are:

• Anemia of inflammatory disease

• Anemia of chronic kidney disease

• Blood loss (trauma, gastrointestinal ulcerations, inability to clot, ruptured tumor, parasites - internal and external)

• Blood parasites (Mycoplasma haemofelis, Cytauxzoon felis)

• Immune-mediated (may be associated with Mycoplasma sp., feline leukemia or a primary disease)

• Bone marrow suppression (feline leukemia associated cancers, systemic fungal infection)

• Drug reaction (bone marrow suppression or red cell damage)

Treatment targets specific causes of anemia. Fleas, intestinal and blood parasites, and fungal infections are treated with specific medications. Suspected gastric ulcerations are treated with famotidine and sucralfate. Immune-mediated conditions are treated with corticosteroids.  Other treatments that may be indicated are iron supplementation, injections of medication to stimulate the bone marrow and, if the cat is extremely anemic, a blood transfusion. 

Red blood cells are essential to life, and when their numbers decline it is imperative to find the cause and manage it appropriately.