Myelodysplastic syndromes are group of diseases of the blood and bone marrow (stem cells), a collection of hematological conditions characterized by hampered production of myeloid blood cells. It also involves problems related to blood production (hematopoiesis) characterized by defects in blood-forming cells (hematopoietic cells). During the course of this disorder, bone marrow failure causes worsened cytopenias. Almost 35% patients suffering from this syndrome develop Acute Myelogenous Leukemia in due course of time (varying from couple of months to few years).
Types of Diseases
As already mentioned above, this syndrome is a collection of diseases. They are listed down below:
- Refractory anemia (RA)
- Refractory anemia with ringed sideroblasts (RARS)
- Refractory anemia with excess blasts (RAEB)
- Refractory anemia with excess blasts in transformation (RAEB-T)
- Refractory cytopenia with multilineage dysplasia (RCMD)
- Chronic myelomonocytic leukemia (CMML)
Although the exact causes are still unknown, some of the probable causes, which may lead to MDS are identified as follows:
- Over exposure of toxic chemicals (pesticides, insecticides, fungicides, chemical compounds like benzene, etc.) or radiation to our body is the main cause of development of the syndrome.
- People undergoing cancer treatment, such as radiation and chemotherapy, and use of radiomimetic alkylating agents develop secondary MDS as an effect of late toxicity caused by the treatment.
- Along with these, smoking, congenital diseases (such as Fanconi Anemia), inheritance at some extent, and age are also possible causes.
- Due to unknown reasons, mutation in multi-potent bone marrow stem cells may also occur leading to this disorder.
The symptoms are not very conclusive, as they are non-specific and may vary from patient to patient. Some of the observed signs are:
- Shorter breathes
- Chronic tiredness/weakness
- Chilled sensations
- Periodic chest pain
- Enlargement of the liver (also known as hepatomegaly)
- Enlargement of the spleen (known as splenomegaly)
- Paler skin (in some cases)
- Development of spots under the skin due to bleeding (known as petechiae or ecchymoses)
- Frequent infections
- Formation of abnormal granules in blood
- Abnormality with chromosomes such as number of chromosomes (may increase or decrease abnormally) and chromosomal translocation
- Decrease in neutrophil count (also known as neutropenia)
- Low count of white blood cells, red blood (anemia) cells, and platelets (thrombocytopenia characterized by gum bleeding)
- Blood in stools (in some cases)
Since the symptoms are not very conclusive, it becomes difficult to confirm the syndrome just by observing them. Some diagnostic tests measures:
- Blood cell counts test (Complete Blood Count (CBC) to count number of white blood cells, red blood cells, platelets etc., Peripheral blood smear test etc.)
- Patient's medical history such as treatment involving chemotherapy and radiation therapy
- Family history to confirm inheritance
- Patient's social/work history to check if he/she is anywhere exposed to chemicals
- Physical examination of the patient
- Cytogenetic Analysis (blood cells are examined for changes in chromosomes)
- Bone Marrow Aspiration and Biopsy to check existence of abnormal cells
- Cytochemistry test and Cytogenetics test for chromosomes count
- Flow Cytometry
- Immunocytochemistry and Molecular Genetic Studies
As it is a collection of multiple diseases, the treatment is always based on the type of MDS and particular disease the patient is suffering from. In addition, the patient's age and medical history plays an important part. The treatment options used include:
- Hormone Therapy and Growth Factors: People suffering from MDS are injected with hormones (for example: androgen) or hormone-like substance (for example: erythropoietin), which are important for production of blood cells.
- Use of Immune Suppressive Medication: In some patients, T-lymphocytes create a problem in the production of blood cells. Immune suppressive medication is used to keep a check on the T-lymphocytes to help production of blood cells.
- Chemotherapy: Drugs are used to hamper development of abnormal blood cells, and facilitate production of normal blood cells.
- Angiogenesis Inhibitors: They are used to slow down the growth of MDS in patients. They help our body regain ability of blood cell production and avoid blood transfusion.
- Epigenetic Agents: Epigenetic agents are drugs used to control growth and operation of genes, which are responsible for production of abnormal blood cells.
- Targeted Therapy: In this method, drugs are used to locally hamper production and operation of genes, which are responsible for uncontrolled production of abnormal blood cells.
- Stem Cell Transplant: Chemotherapy drugs are used to treat abnormality, and the entire bone marrow is replaced with a healthy bone marrow. There are mainly two types of stem cell transplants, out of which only the allogeneic stem cell transplant is used for treatment.
- Supportive Treatment: This treatment is used to treat the symptoms of MDS in patients, and help them come over fatigue, low blood cell count, etc.