Myelodysplastic syndromes (MDS) are diseases in which the bone marrow does not function properly and fails to produce enough normal blood cells. Bone marrow is the tissue inside the bones where blood cells are made. Immature bone marrow cells called blasts normally develop into several types of blood cells that serve different purposes. In MDS, the bone marrow produces too many identical, abnormal blasts. The body destroys the abnormal cells, and not enough normal red or white blood cells or platelets are made. Too few red blood cells, which carry oxygen from the lungs to the tissues, result in anemia. White blood cells help fight infection. Platelets are necessary for blood clotting.

MDS is sometimes called sideroblastic anemia. MDS used to be called preleukemia because it can worsen and become a type of leukemia, a cancer of the blood that is usually fatal. Myelodysplastic syndromes are grouped together into five types, based on how the bone marrow cells or blood cells look. It can change from one type to another.
How does it occur?

MDS may occur due to:

• Reasons unknown: Some older adults develop MDS for no apparent reason. In most of these cases, the condition is so mild it does not require treatment. However, a few people later develop acute leukemia.
• Medications for other diseases: It may develop as a side effect of medications used to treat diseases such as leukemia, lymphoma, or rheumatoid arthritis. In these cases, the condition usually is mild, except when due to prior chemotherapy exposure.
• Exposure to certain drugs or toxins: It is usually associated with alcoholism, lead poisoning, or taking the antituberculosis drug isoniazid (also called INH, Laniazid, and Nydrazid). These substances interfere with red blood cell production in the bone marrow. In these cases, the MDS can be mild or severe.
• Heredity: Although it happens rarely, you may have been born with it. Because of how it is inherited, it is usually a disease of males. These cases are generally detected in the late teen years and can be quite severe.

Symptoms may include:

• lack of energy
• shortness of breath
• blood-clotting problems, which can make it hard to get cuts to stop bleeding. You may also have bleeding gums, blood in the urine, and nosebleeds
• infections.

Your health care provider will ask about your symptoms and medical history and will examine you. Blood tests will be done. Based on the results of your blood tests, your health care provider may perform a bone marrow biopsy. In this procedure, bone marrow is removed from your hip with a needle and then examined under a microscope.
How is it treated?

The treatment depends on the cause of the myelodysplastic syndrome. If you have the hereditary form, vitamin B6 may be helpful. If it is caused by medications you are taking for another disease, your health care provider will need to change your medication. When the MDS is caused by drugs or toxins, avoiding further contact with the drug or toxin will help keep more damage from occurring. When the cause is not known, treatment is usually not needed.

Regardless of the cause, blood transfusions are often needed to bring the amount of red blood cells closer to normal. When many transfusions are given, however, a the result can be a buildup of too much iron in your body.

In patients under age 50 who can tolerate the procedure, a bone marrow transplant may be an option. It is not always successful, however.

Erythropoietin (EP), a hormone produced by the kidneys, is sometimes given by injection into the skin to stimulate the bone marrow to make more blood.
How can I help myself?

• Follow your health care provider's treatment plan.
• Tell your provider at once if your symptoms get worse.