Hemolytic Anemia in Cats

Normally, red blood cells are made in the bone marrow, they age, die and are recycled into new ones. Low red blood cell count can be a result of the bone marrow not manufacturing these cells as fast as the old cells are dying. Another cause of low red blood cell count is autoimmune hemolytic anemia (AIHA), also called Immune-Mediated Hemolytic Anemia or IMHA, which occurs when the body destroys its own red blood cells. There are two types of AIHA, the primary type is not as common in cats and occurs when the body mistakenly attacks it own healthy red blood cells. The secondary type of AIHA occurs when a disease, such as feline leukemia virus (FLV), feline immunodeficiency virus (FIV), cancer, or a toxin, alters the red blood cells so that the cat's body sees them as foreign objects and produces antibodies to destroy them. This secondary type is more common in cats.

Hemolytic anemia in cats occurs when there is a loss of red blood cells, either because the body is not producing enough new red blood cells to replace old ones or because the body is destroying them. Red blood cells contain hemoglobin which delivers oxygen via the blood to tissues throughout the body. A low blood cell count, or low hemoglobin, results in anemia which causes reduced oxygen to be delivered to your pet's body tissues.

The symptoms of hemolytic anemia in cats are related to lack of oxygen being delivered to the body’s tissues. These symptoms include:

• Pale gums
• Listlessness
• Labored breathing
• Increased heart rate
• Poor appetite

Eventually, breakdown of red blood cells can cause bilirubin buildup which produces symptoms of jaundice. Gums and mucous membranes appear yellowish and dark urine is produced.

The following can cause the immune system to destroy red blood cells or reduce the production of these cells by the bone marrow.

• Malfunctioning of the immune system
• Feline immunodeficiency virus
• Feline leukemia virus
• Parasitic infection
• Toxins such as onions, zinc or acetaminophen (Tylenol)
• Bone marrow disorder
• Cancer
• Bacterial infection
• Viral infection
• Renal disease

When a cat presents with symptoms of anemia, your veterinarian will first rule out traumatic blood loss as a cause to confirm a diagnosis of hemolytic anemia. The pet owner will be asked to provide a history of possible injury or toxic exposures. In cases of suspected hemolytic anemia a complete blood count (CBC) test will be ordered by the veterinarian to

determine the number and percentage of red blood cells and also to check for abnormalities in cells. By examining a blood smear under a microscope, your veterinarian can detect structural abnormalities in red blood cells that may be causing the immune system to react to them. In addition, a reticulocyte test which examines immature red blood cells can identify problems with red blood cell production. Tests for feline leukemia virus , feline immunodeficiency virus, and parasites, which are common causes of hemolytic anemia in cats, will be performed.

Additional tests such as urinalysis, x-rays or ultrasound to check for underlying causes such as infection or cancer also may be performed.

Bone marrow biopsies will be performed in cases which decreased production of new red blood cells is suspected as a cause of the anemia.

Hemolytic Anemia is an urgent medical condition and can result in death if not treated by your veterinarian immediately. Treatment will address both the symptoms of anemia and the underlying cause of your pet’s hemolytic anemia.

While mild anemia can be treated with iron supplements, severe cases may require blood transfusion. In addition, intravenous fluids may be administered to counteract dehydration that may result from your pet not taking in enough fluids due to weakness and listlessness from the anemia.

Prognosis of hemolytic anemia depends on the underlying cause and effectiveness of treatment. In primary AIHA, immunosuppressive medications may be administered to stop the immune system from destroying red blood cells. In secondary AIHA, the cause of damage to the red blood cells will be addressed. In cases of hemolytic anemia which bacterial or parasitic infection is a factor, antibiotics or antiparasitic medication will be administered. When viruses such as FIV and FLV are causal factors, the virus will be treated and managed as appropriate.

In cases of primary AIHA, relapse is more likely and your cat will be monitored closely for signs of relapse.

Recovery from hemolytic anemia depends on the effectiveness of treatment of the cause. Cats recovering from hemolytic anemia should be given a low-stress environment, rest, and adequate fluid during recovery.

Where virus such as FIV or FLV are involved, your cat should be kept indoors and separate from other cats to prevent the spread of infection.

With immune system disorders, relapse is possible and you should closely monitor your cat and seek veterinary help immediately if signs of relapse occur.