By Dr. Becker
Anemia is a condition characterized by a below-normal number of circulating red blood cells. Red blood cells contain hemoglobin, a protein that carries oxygen to all the tissues of the body. When a cat doesn’t have enough circulating red blood cells, oxygen can’t get into the tissues as required.
Regenerative and Non-Regenerative Anemia
Anemia can be caused by blood loss or red blood cell destruction, called hemolysis, which is considered regenerative anemia. In regenerative anemia, the bone marrow is capable of producing more red blood cells, but oftentimes not quickly enough to replace what is being lost.
Anemia can also be caused by inadequate red blood cell production, which is considered non-regenerative anemia, a condition in which the bone marrow is unable to produce enough red blood cells.
Causes of Regenerative and Non-Regenerative Anemia
Causes of regenerative anemia include hemorrhage brought on by an accident or internal bleeding; parasites; immune-mediated hemolytic anemia, which occurs when a cat’s body attacks its own red blood cells; and Heinz body hemolytic anemia. Other causes include certain medications, foods, or toxins like acetaminophen or propylene glycol, which is antifreeze; and copper, zinc, and onion toxicosis. A highly unusual cause of feline anemia is a rare condition called neonatal isoerythrolysis -- an immune-mediated condition in which kittens with type A blood drink colostrum from a mother with type B blood.
Causes of non-regenerative anemia include feline leukemia virus (FeLV) or feline immunodeficiency virus (FIV), certain types of cancers, poor nutrition or starvation, and chronic inflammatory disease.
Anemia Caused by Chronic Kidney Disease
One of the most common causes of non-regenerative anemia in cats, especially middle-aged or older kitties, is chronic kidney disease.
As I mentioned above, production of red blood cells takes place in the bone marrow. In order for the process to work, the bone marrow needs an adequate supply of erythropoietin, or EPO. EPO is a glycoprotein hormone produced by the kidneys, and cats with chronic kidney disease often can’t produce enough of this hormone to supply the bone marrow. If the bone marrow can’t get enough EPO, anemia is the result.
In addition, the lifespan of red blood cells in cats with kidney disease is about half that of healthy cats, which is another reason why kitties with kidney problems often develop secondary anemia.
Symptoms of Anemia
A cat with anemia isn’t getting enough oxygen to the cells of her body, so symptoms reflect oxygen deprivation and can be vague or diffuse. They can include pale mucus membranes or gum color, lethargy, and sleeping more.
Your kitty may have a loss of appetite or diminished appetite. She may have black, tarry stools if she’s bleeding internally or from the GI tract. There can also be weight loss, generalized weakness, a rapid pulse or breathing, and a heart murmur.
A very important test for anemia is of course the complete blood count. An elevated number of immature red blood cells called reticulocytes usually points toward regenerative anemia, which is the type caused by blood loss or red blood cell destruction.
A blood smear is useful to check for the presence of blood-borne parasites as well as abnormalities in the physical appearance of red blood cells. A biochemical profile helps to evaluate a cat’s general health and determine organ involvement, if any.
A fecal exam is used to check for blood loss from the gastrointestinal tract. X-rays and ultrasound exams can help your vet visualize internal organ size and the potential presence of foreign objects or tumors inside your cat’s body.
In cats with non-regenerative anemia, a Coombs test is performed to look for antibodies against red blood cells, which indicates immune-mediated hemolytic anemia. In worst-case scenarios, a bone marrow biopsy will be performed to confirm certain types of cancers.
Finding the cause of your cat’s anemia is crucial, since anemia is actually a symptom of something else wrong in the body. Treatment will then depend on the cause and severity of the condition.
In cases of mild regenerative anemia, no treatment may be needed since the body still has the ability to produce red blood cells. Your pet’s bloodwork will be monitored until red blood cell counts return to normal, and periodically thereafter to make sure the anemia hasn’t recurred.
Holistic veterinarians often supply B vitamins and chlorophyll supplements during this time, which can help mildly anemic cats recover faster.
In cases of non-regenerative anemia caused by chronic kidney disease, depending on the severity, your vet may recommend the use of erythropoiesis-stimulating agents (ESAs) like Epogen to increase production of red bloods from the bone marrow. As with all medications, however, these drugs do have side effects, so I would want to consider acupuncture and blood-building supplements first.
Other traditional treatments depend on the cause of the anemia. Again, getting a diagnosis as to what’s causing the anemia is really important. In cases of acutely anemic cats and certain other situations like trauma, blood transfusions may be necessary.
Untreated feline anemia has the potential to be fatal. It’s important to investigate both the anemia and the underlying cause as soon as possible.