Stem Cell Disorder in Cats

This stem cell disorder will result in low blood cell counts, which is called cytopenia, which can, in turn, cause anemia, which refers to low red blood cell counts, neutropenia, which is a low white blood cell count, and thrombocytopenia, which is the medical term for a low platelet count. These low counts can result in infection, bleeding, and easy and excessive bruising. If you are concerned that your cat may be suffering from a stem cell disorder, it is imperative that you contact your veterinarian immediately to schedule an appointment, as MDS and the underlying disease that has caused it can be terminal if not treated.

A stem cell is a cell that has not yet differentiated into a particular cell such as a red blood cell, white blood cell, or platelet. These stem cells are produced in the bone marrow. A stem cell disorder, usually referred to as myelodysplastic syndrome (MDS), occurs when the bone marrow becomes unable to produce enough stem cells, the stem cells are unable to fully develop, or the stem cells do not live long enough to become blood cells. 

The early stages of any form of stem cell disorder can be difficult to detect. Quite often by the time a cat begins to display symptoms the underlying condition is in an advanced stage. Regardless of what the underlying cause may be, if you suspect that your cat may have a stem cell disorder, it is imperative that you call your veterinarian immediately. Some or all of the following symptoms may be present in a cat with myelodysplastic syndrome:

• Lethargy
• Easy and excessive bruising
• Spontaneous bleeding 
• Bleeding that is difficult to stop
• Loss of appetite
• Pale gums
• Jaundice
• Weight loss
• Persistent infections

Myelodysplastic syndrome is not usually a disease in and of itself, but rather a collection of symptoms that are the result of an underlying disease or condition. The following conditions have been found to cause stem cell disorders in cats:

• In cats, the disease that is most often the cause of MDS is leukemia, which is caused by the feline leukemia virus (FeLV). FeLV is contagious among cats, spread through saliva and mucous. Cats that are most at risk are young, sick, old, or outdoor cats that may get bitten by an infected cat.
• Bone marrow mutations, which are often idiomatic, meaning their cause is unable to be determined.
• Neoplasia, which is the growth of a neoplasm, an abnormal growth of tissue commonly referred to as a tumor.
• Adverse reactions to drug therapy for other conditions.

If you are concerned that your cat might suffer from a stem cell disorder and a possible underlying condition, it is very important that you contact your veterinarian immediately so that your cat can be examined. If your veterinarian suspects a stem cell disorder, the vet will likely utilize some or all of the following diagnostic tools:

• Listening to your observations of the symptoms and reviewing the cat’s medical history.
• A thorough physical examination
• Urinalysis
• Complete blood count, which will be extremely important in diagnosing a stem cell disorder.
• Bone marrow aspiration and biopsy

Veterinary treatment of myelodysplastic syndrome will need to address both the MDS and the underlying cause if it can be determined. These treatments may include the following:

• Antibiotics to fight secondary infections
• Prednisone, a catabolic steroid
• Blood transfusions
• Human recombinant erythropoietin (HRE), which is a hormone that has proven effective in treating anemia in some cats.
• If the cat has been diagnosed with advanced feline leukemia, the vet may prescribe chemotherapy and/or antiviral drugs

The prognosis for cats with stem cell disorders is highly dependent upon the underlying cause and the overall level of health in the cat. A cat that is very young, chronically unhealthy, elderly, or that has gone untreated for an extended length of time will likely have a poor prognosis. Cats with severe cases of myelodysplastic syndrome, especially when it is caused by advanced leukemia, can die or may need to be humanely euthanized because of severe and untreatable bleeding, infection, and anemia.

A cat with MDS that can be treated and managed may need to be declawed or have the claws dulled on a regular basis in order to prevent accidental cutting of the skin. The cat will need to remain indoors and separate from any other pets or small children that may cause harm that leads to bruising or the breaking of the skin. The pet owner will need to take all possible precautions to keep the cat from contracting any other sicknesses, as the body’s ability to fight off infection will likely be seriously compromised.