What are the Myelodysplastic Syndromes?

The myelodysplastic syndromes, formerly known as preleukemia, are a group of hematological disorders caused by blood cells that are dysfunctional or malformed. When something goes awry in a person’s bone marrow, these syndromes can result. Although there is no cure, treatment is available that works to reduce and prevent complications and symptoms. Sometimes a bone marrow transplant is necessary to help prolong a patient’s life. Myelodysplastic syndromes can be present in humans, cats, and dogs.

The bone marrow disorders that characterize this group of syndromes cause ineffective blood production. For most patients, the condition is chronic and will gradually worsen. Progressive bone marrow failure will result in the steady decrease of healthy blood cells.

Doctors divide myelodysplastic syndromes into two categories according to the cause: those with no known cause and those caused by radiation and chemicals. The World Health Organization further divides the syndromes into six subtypes according to the type of cell affected. Myelodysplastic syndromes without a known cause are typically easier to treat.

Chemotherapy and radiation for cancer or chemical exposure can lead to myelodysplastic syndromes. Tobacco smoke and pesticides have been linked to these disorders, as have certain heavy metals such as mercury and lead. Men are more frequently affected than women, and most cases are in people who are older than 60 years.

There are few symptoms in the early stages of myelodysplastic syndromes. As the condition worsens, a person with these syndromes may notice increased fatigue, paleness, and easy bruising. Shortness of breath, frequent infections, and small red spots beneath the skin called petechiae are additional signs. If any of these symptoms are present and worrisome, a medical professional should be consulted as soon as possible.

A diagnosis of myelodysplastic syndromes is typically made based on the results of blood tests, including a complete blood count and a peripheral blood smear. The latter examines the blood for unusually shaped blood cells. A sample of bone marrow may also be removed to check for abnormalities.

Treatment focuses on managing symptoms and complications like fatigue and anemia, and preventing problems like infections and bleeding. Blood transfusions are commonly used to help replace blood cells. Medications are given to help the body produce more blood cells or to suppress the immune system. A bone marrow stem cell transplant may also be a treatment option, but the risk of complications is high even in young and healthy patients.

About one-third of people with myelodysplastic syndromes will progress to acute myelogenous leukemia (AML) in a few months or years. AML is a form of cancer that causes abnormal white blood cells to accumulate in the bone marrow and disrupt the production of normal blood cells. It is the most common acute leukemia in adults, although it is relatively rare.