OVERVIEW
Myelodysplastic syndromes (MDS) also referred to as myelodysplasia are a group of conditions involving the bone marrow which is the factory that produces blood cells.
In MDS, the blood cell (red cells, white blood cells and platelets) formation by the bone marrow becomes faulty.
The marrow does not produce enough blood cells and the ones that are formed do not function properly
As a result of faulty production and/or function of blood cells, the patient develops anemia, thrombocytopenia and is at increased risk of getting infections due to neutropenia
It is a form of precancer and can transform into acute myeloid leukemia over a period of time[/color] that may vary from several months to years

CAUSES & RISK FACTORS OF MDS
In some cases of MDS, the etiology remains unknown
Risk factors of developing MDS include
Older age group
History of previous cancer chemotherapy
Exposure to chemicals such as pesticides, tobacco and industrial chemicals such as benzene
Exposure to heavy metals such as lead, mercury

TYPES OF MDS
The World Health Organization subdivided MDS into 6 subtypes based on the type of blood cells — red cells, white cells and platelets — involved.
• Myelodysplastic syndrome with unilineage dysplasia – Only one blood cell type i.e, white blood cells, red blood cells or platelets are decreased in number and show abnormal features (dysplasia) on microscopic examination
• Myelodysplastic syndrome with multilineage dysplasia – In this type, two or three blood cell types are reduced and abnormal in morphology
• Myelodysplastic syndrome with ring sideroblasts – There is reduced number of one or more blood cell types. A characteristic feature is that the bone marrow red cells contain a ring of excess iron called ring sideroblasts, which is visible as a rim of iron on special stains
• Myelodysplastic syndrome associated with isolated del chromosome abnormality – People with this syndrome have reduced number of red blood cells, and show a specific mutation in their DNA.
• Myelodysplastic syndrome with excess blasts — types 1 and 2 – In both these syndromes, either of the three types of blood cells — red blood cells, white blood cells or platelets — might be reduced with abnormal features. In addition, excess of very immature blood cells (blasts) or early forms of the blood cells are found in the blood and bone marrow.
• Myelodysplastic syndrome, unclassified – This type is uncommon, in which there are reduced numbers of either one of the three types of mature blood cells, and either the white blood cells or platelets display abnormal morphology.

SYMPTOMS OF MDS
In the initial stages, the patient generally is asymptomatic and the condition is often discovered incidentally during routine blood tests followed by further investigations. With progression of disease, the following symptoms may be encountered due to reduced numbers and faulty function of the blood cells
• Tiredness and fatigue (due to anemia or reduced red cells)
• Shortness of breath, especially on exertion (anemia)
• Unusual paleness (pallor) due to a low red blood cell count (anemia)
• Easy or abnormal bruising or bleeding which occurs due to decreased platelet count (thrombocytopenia)
• Pinpoint-sized red spots just underneath the skin caused by bleeding (petechiae) due to low platelet count
• Frequent and recurrent infections which (due to a low white blood cell count or leukopenia)

COMPLICATIONS OF MDS
Increasing tiredness and shortness of breath due to severe degree of anemia
Life threatening bleeding due to reduced platelets
Recurrent infections that may be serious and impair the quality of life
Risk of transformation to acute myeloid leukemia (AML)

DIAGNOSIS OF MDS
Diagnosis of MDS may be suspected by physical exam, and medical history and further tests may be done to confirm the diagnosis. In some cases the diagnosis may be made incidentally on routine blood tests such as full blood count

• Blood tests – A full blood count may reveal reduced numbers of one or more blood cells. Examination of a blood film (peripheral smear) under microscope can confirm decreased number and morphology of the blood cells
• Bone marrow examination – During a bone marrow biopsy and aspiration, a thin needle is used to draw out (aspirate) a small amount of liquid bone marrow, usually from a spot on the back portion of the hipbone. Additionally small piece of bone with its marrow is removed (trephine biopsy). Bothe the aspirate and trephine are examined under the microscope to look for features suggestive of MDS

TREATMENT OF MDS
The nature of treatment depends on the subtype of MDS, the risk of developing AML, and presence of associated health conditions. The treatment aims to improve the numbers of the blood cells in the blood stream and to control the symptoms of the disease. If the MDS is only low risk to transform into AML, a watch and wait approach may be taken with regular monitoring with blood tests.

SUPPORTIVE TREATMENT
Symptoms of MDS can usually be kept under check with the following supportive treatments
• Growth factor drugs, such as erythropoietin or G-CSF to promote the formation of healthy red or white blood cells respectively by the bone marrow
• Transfusion – of either red blood cells or platelets, depending on the clinical picture
• Drugs eg desferrioxiamine to remove excess iron buildup in blood – which can build due to repeated transfusions
• Antibiotics to treat infections when white blood cell count is low

MEDICAL TREATMENT
Lenalidomide, a form of biological treatment can be used to treat a rare type of MDS called deletion 5q, or del(5q). It alters how the immune system functions
Azacitidine is given to patients with more serious types of MDS, in order to improve marrow function and slow down progression of MDS.
Chemotherapy may be advised to patients at increased risk of transformation to AML

STEM CELL TRANSPLANT
A stem cell transplant (also referred to as a bone marrow transplant) may be offered after chemotherapy. The patient’s abnormal blood cells are replaced with healthy cells from a donor into the bloodstream via a drip. It can cure MDS but not all patients will be eligible to undergo this treatment