Anemia in Dogs and Cats-When There's Not Enough Blood

Anemia—When There’s not Enough Blood

               Anemia, a decreased number of red blood cells in the body, is a fairly common problem in dogs and cats.  What can happen if a pet is anemic?  Lack of red blood cells can lead to decreased oxygen carrying capacity in animals which causes symptoms of lethargy, weakness, and decreased activity, pale gums, panting or difficulty breathing, decreased appetite and sometimes collapse.  Sometimes, an odd behavior known as pica, eating non-food objects such as dirt or cat litter, may occur in anemic animals.  If enough blood cells are lost, severe anemia may lead to death.

               There are three main causes of anemia in pets:  blood loss, red blood cell destruction and lack of red blood cell production. 

               Blood loss can occur with an acute or sudden injury; for instance, a cut or laceration causing bleeding, blood loss from organ damage due to blunt trauma such as being hit by a car, or bleeding from a tumor such as hemangiosarcoma on the spleen.  Toxins such as rat poison may also cause internal bleeding.  Blood loss may also be slow and chronic such as from a bleeding ulcer in the stomach, chronic blood loss through the urinary tract, or blood loss from a severe intestinal parasite or flea infestation.  

               Destruction of red blood cells can occur for several reasons.  Immune mediated hemolytic anemia is the most common cause of red cell destruction—something triggers a defect in the patient’s immune system that causes it to attack and break down the body’s own red blood cells.  Destruction may also occur with certain bacterial, viral and protozoal infections that target red blood cells, by certain toxins such as acetaminophen toxicity in cats, or by certain rare, inherited defects affecting red blood cell life span.

               Lack of production of red blood cells can occur if there is disease in the bone marrow such as cancer or lack of production of hormones that stimulate red blood cell production which may occur in patients with chronic kidney disease or other chronic illnesses. 

               Patients are most often diagnosed with anemia based on physical exam findings of pale gums or signs of active blood loss if present.  Blood tests often confirm the severity and type of anemia.  Samples of tissue from the bone marrow and other diagnostic tests may be needed in some cases to determine the underlying cause.

               Treatment varies based on the underlying cause.  A normal red blood cell count (known as packed cell volume or hematocrit) is typically 35-45%.  In severe cases of anemia where massive acute blood loss is evident or when the blood count drops below 15%, a blood transfusion may be required to stabilize the patient and allow time to treat the underlying problem.  Immune destruction of red blood cells usually requires steroid or other immunosuppressing drugs.  Patients may require surgery in the case of trauma or cancer.  Infections require specific treatments. Chronic anemia secondary to fleas or parasites require treatment to kill the parasites and chronic anemia secondary to kidney disease may be treated with medications to stimulate the bone marrow to produce more red blood cells.  A blood transfusion may be beneficial, but does not always correct the underlying cause of the anemia.

               Iron deficiency is a much rarer cause of anemia in dogs and cats, though chronic blood loss or inadequate absorption of iron from the diet occasionally cause this issue. Iron supplementation will not correct most causes of anemia, but it may be necessary in some cases of chronic anemia or if certain lab changes are present on a complete blood count.  DO NOT start iron supplements for your dog or cat without consulting your veterinarian.  Too much iron can be toxic and even fatal to pets and iron is beneficial in only a small number of cases.

               If your pet exhibits any of the symptoms listed, especially pale or white gums or extreme lethargy, have him or her seen by your veterinarian immediately.  While in most cases pets can be treated, anemia is very serious and some forms may even be deadly.

               This blog brought to you by the Patton Veterinary Hospital serving Red Lion, York and the surrounding communities.

https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/anemia