The bone marrow, which is the spongy material inside of bones, is responsible for making many of the cells that circulate in the blood. The bone marrow contains special cells, called blood stem cells, which are able to produce these mature blood cells. Myelodysplasia is a condition in which these blood stem cells are defective.
Pathology
Myelodysplastic syndrome, the National Cancer Institute explains, is a disease of the bone marrow that affects blood stem cells. Blood stem cells are cells that are able to turn into the three main blood cells, known as white blood cells, platelets and red blood cells. Myelodysplasia causes these cells to have problems when they get to the "blast" stage, which is a step on the way to the differentiation into mature blood cells. These abnormal blasts either die prematurely or are unable to continue developing, resulting in deficiencies in the amounts of blood cells in the body.
Symptoms
During the early stages of the disease, the Mayo Clinic explains, there may not be any symptoms as it can take some time for the blood cell deficiencies to cause any significant problems. The most common symptom of more severe myelodysplastic syndromes is anemia, which can manifest itself as chronic fatigue, pallor and shortness of breath as a result of poor oxygen circulation. Patients may also be prone to bleeding or bruising easily and can develop frequent infections as a result of a lack of white blood cells. Some patients also develop small red spots, called petechiae, as a result of bleeding under the skin.
Risk Factors
Patients that are over the age of 60, the Mayo Clinic notes, make up the majority of patients with myelodysplasia. This problem also occurs more frequently in men. Patients who have received chemotherapy or radiation treatment to treat cancer are also prone to developing this disease. Myelodysplasia can also be the result of exposure to certain chemicals, such as benzene, pesticides, lead and mercury.
Diagnosis
Myelodysplastic syndrome, according to the National Institute of Diabetes and Digestive and Kidney Disorders, is typically diagnosed using blood tests. These tests can identify low numbers of any or all of the blood cells. This test may also show the presence of many immature blasts in the blood. A bone marrow biopsy is necessary, however, to distinguish myelodysplasia from other bone marrow problems. The biopsy will show the presence of many abnormal blasts and few mature blood cells.
Treatment
Because there is no cure for myelodysplasia, the National Institute of Diabetes and Digestive and Kidney Disorders notes that treatment typically focuses on supportive care. This often includes blood transfusions and antibiotics to minimize the effects of the low blood cell levels. Patients may also receive erythropoietin, which stimulates the production of red blood cells. Azacitidine, lenalidomide and decitabine are medications which may also be used to treat myelodysplasia; these drugs can increase the ability of the bone marrow to make functional blood cells. Severe cases of myelodysplasia can be treated by using high doses of chemotherapy to destroy the defective bone marrow cells, allowing any remaining healthy cells to repopulate the bone marrow. This treatment is generally not an effective long-term approach, however.
