“Leukopenia” is a decrease in the number of total white blood cells found in blood, which for your cat can be rather bad news. After all, white blood cells comprise the defense team that protects against common illnesses and serious infections.
So what causes a low white blood cell count in cats? First it helps to understand the makeup of white blood cells, also known as leukocytes, and their functions:
- Neutrophils and Eosinophils are released into the bloodstream to destroy bacteria.
- Lymphocytes are produced in the lymph nodes and spleen.
- Monocytes are stored in the spleen and bone marrow.
- Researchers aren’t entirely clear as to the main purpose of basophils.
A normal white blood cell count in cats typically ranges from 5,500 to 19,500 per microliter of blood. To determine your cat’s count the vet will run a complete blood count. Low levels of neutrophils and lymphocytes circulating the blood indicate that these cells are at the site of an infection, or that sepsis has occurred. This drop is typically temporary, with counts rising to normal in a few days.
Why a Cat Would Have a Low White Blood Cell Count
Viral infections are the most common cause of a low white blood cell count in cats. Feline Immunodeficiency Virus (FIV) and Feline Infectious Peritonitis (FIP) are two such viruses. These viruses invade the white blood cells and use them to make copies of themselves, increasing the virus’ strength and reducing the number of white blood cells.
Other causes include:
- Bacterial infections. These infections can range from abscesses to respiratory infections to sepsis.
Essentially, any infection or inflammation causes a drop in white blood cells, particularly neutrophils.
- Bone marrow diseases, or the panleukopenia virus, which destroys the marrow where white blood cells are produced.
- Pancreatitis. The inflammation of the pancreas will draw white blood cells from the bloodstream, lowering their count.
- Certain medications. Corticosteroids, which are used to treat arthritis can actually suppress the production of white blood cells.
- Stress. As a response to stress the cat’s immune system may begin to repress itself, resulting in a decreased production of white blood cells.
How Will I Know if My Cat is Sick?
Symptoms are typically related to the cause of the high white blood cell count.
- If the cause is a viral infection such as Feline Immunodeficiency Virus, symptoms will appear as fever, moodiness, swollen lymph nodes, lack of appetite, fatigue, inflammation of the gums, nasal and eye discharge, vomiting, bloody diarrhea, and hair loss. Feline Infectious Peritonitis symptoms include those of Feline Immunodeficiency Virus, as well as fluid buildup in the lungs, difficulty breathing, distended abdomen, frequent urination, and jaundice.
- If the cause is a bacterial infection, symptoms will appear as fever, lack of appetite, moodiness, and fatigue. If the infection is external, there may be a rash, wound, or abscess. If the infection is internal, additional symptoms could include swollen lymph nodes, muscle and joint pain and stiffness, vomiting, and diarrhea.
- If the cause is a bone marrow disease such as panleukopenia, symptoms will be fever, lack of appetite, vomiting, diarrhea, and fatigue.
- If the cause is pancreatitis, symptoms will appear as trouble breathing, fatigue, lack of appetite, and lower than normal body temperature. Unlike dogs, cats typically do not vomit or exhibit abdominal pain.
- If the cause is a medication, the symptoms can vary. Your cat could exhibit anything from fever and moodiness to lack of appetite and diarrhea, which is why it’s best to discuss every new medication with your vet.
- If the cause is stress, symptoms will likely appear as aggression, decreased social interaction, lack of appetite, and hair loss.
Getting Your Cat’s White Blood Cell Count Back Up
If your cat’s white blood cell levels are low, your vet will recommend a treatment based on the cause of the issue.
- There are unfortunately no medications that can combat viruses. When it comes to a viral infection like Feline Immunodeficiency Virus or Feline Infectious Peritonitis, the main focus is supportive care, such as increasing fluids, devising a nutrient-rich diet, and administering antibiotics to prevent and treat secondary infections that may occur. Unfortunately, most cases of FIP lead to death, but there are reliable vaccines to prevent such viruses from taking hold.
- Bacterial infections can be treated with a variety of medications, particularly antibiotics.
- Bone marrow disease is incurable and care will be supportive. In severe cases, blood transfusions may be necessary. However, there is a reliable vaccine to prevent the condition.
- Hospitalization may be recommended for cats suffering from pancreatitis. During your cat’s stay, fluids and pain and anti-inflammatory medications will be administered.
It is import that you stay up to date with your cat’s wellness visits, in which your vet will run routine blood cell counts in an effort to spot any underlying health issues.
More on Cat Health
Why Is My Pet Coughing?
The Truth About Toxoplasmosis in Cats
5 Ways to Prevent Feline Cystitis
This information is for informational purposes only and is not meant as a substitute for the professional advice of, or diagnosis or treatment by, your veterinarian with respect to your pet. It has, however, been verified by a licensed veterinarian for accuracy.