Myelodysplastic Syndrome

 

The myelodysplastic syndrome (MDS) is a collection of blood-related medical conditions that involve ineffective production of the myeloid class of blood cells. It was formerly known as preleukemia It leads to the development  severe anemia causing the disease worsens and the patient develops cytopenias (low blood counts) caused by progressive bone marrow failure.the clients with MDS require frequent blood transfusion. So the prognosis of Mylodyslastic syndrome is poor, and 20 to 30% of patients will progress within a few months or years to refractory acute myeloid leukemia. The myelodysplastic syndromes  includes all disorders of the stem cell in the bone marrow. In MDS, hematopoiesis (blood production) is ineffective and disorderly. In myelodysplastic syndromes there will be irreversible reduction in the number and quality of blood-forming cells, further impairing blood production.

 Myelodysplastic syndrome  

  • Definition of myelodysplastic syndromes

  • The incidence of myelodysplastic syndrome

  • Main causes of myelodysplastic  syndrome

  • Classification of myelodysplastic syndrome

  • Identify  differential diagnosis of myelodysplastic syndrome

  • Signs and symptoms of myelodysplastic syndrome

  • Laboratory evaluation of myelodysplastic syndrome

  • Treatment of myelodysplastic syndrome

  • The prognosis  of myelodysplastic syndrome

  • Conclusion

 

Definition of myelodysplastic syndromes

          Myelodysplastic syndromes (MDS) are a group of acquired clonal disorders affecting the hematopoietic system and characterized by cytopenias with hypercellular bone marrow and various morphologic abnormalities in the hematopoietic cell lines.

The incidence of myelodysplastic syndrome

              The median age at diagnosis of a Myelodysplastic syndrome (MDS) is between 60 and 75 years; in fewer patients it is younger than 50.  In children MDS diagnoses are rare . It is slightly more common in Males than females.

Main causes of myelodysplastic  syndrome

             Myelodysplastic syndrome   occur when their is interruption the production of the blood cells.In this condition as the normal rate and controlled production of  blood cells is affected there will be a lot of immature and defective cells in the bone marrow. This cells die in the bone marrow or immediately entering in to the circulation.As it continue this immature cells will be more than the normal cells which may lead to anemia, bleeding suddenly from the injured site and increased risk of infection.On the basis of etiology it is classified in to two.

            De  novo myelodysplastic syndromes is types in which the etiology is unknown or it is a type of myelodysplastic syndrome with no known cause.So this condition is easy to treat with compared to that of  myelodysplastic syndrome with a cause.

            Certain chemicals and radiations can cause myelodysplastic syndrome.It is more common found in  the cancer clients undergoing chemotherapy and radiation therapy.This is called as secondary myelodysplatic syndrome as it occurs due to the exposure of chemicals.

Classification of myelodysplastic syndrome

            Myelodysplasia encompasses several heterogeneous syndromes. The FAB classification of myelodysplastic syndromes is based on the proportion of immature blast cells in the blood and marrow and on the presence or absence of ringed sideroblasts or peripheral monocytosis. In 1999, the WHO modified the FAB by incorporating newer morphologic insights and cytogenetic findings. It includes the following disease subtypes: refractory anemia with or without excessive blasts, refractory cytopenia with multilineage dysplasia and ringed sideroblasts. Unclassified myelodysplastic syndrome associated with isolated del(5q).

Identify differential diagnosis of myelodysplastic syndrome

Cytogenetic analysis by conventional metaphase karyotyping should be performed in patients with MDS.

      Congenital Disorders.

  • Hereditary sideroblastic anemia.
  • Fanconi’s anemia.
  • Diamond-Blackfan syndrome.
  • Kostmann’s syndrome.
  • Schwachman syndrome.
  • Down syndrome.
  • Vitamin or iron deficiency.
  • B12, folate, or iron deficiency.

 

      Drug Toxicity.

  • Bone marrow suppression from oral or parenteral medications.
  • Toxins.
  • Chemotherapy therapy.
  • Radiation therapy.
  • Alcohol.

 

     Anemia of Chronic Disease.

  • Renal failure.
  • Chronic infection, including tuberculosis.
  • Rheumatologic disorders.

 

       Viral Marrow Suppression.

  • Including Epstein-Barr virus, parvovirus B19, HIV, and others.

 

       Marrow Infiltration.

  • Acute and chronic leukemias.
  • Metastatic solid tumor infiltration.

        Paroxysmal Nocturnal Hemoglobinuria.   Hypersplenism.

Signs and symptoms of myelodysplastic syndrome

  • Spleenomegaly  due to myelodysplastic syndrome.
  • Anemia (low RBC count or reduced hemoglobin) —chronic fatigues or tiredness, shortness of breath, chilling sensation, sometimes slight chest pain.
  • Neutropenia (low neutrophil count) —increased susceptibility to infection.
  • Thrombocytopenia (low platelet count) —increased susceptibility to bleeding and ecchymosis (bruising), purpura or petechia may develop due to subcutaneous hemorrhaging.
  • Abnormal nuclear shape and size granules in cells and size.
  • Chromosomal anomalies mainly translocation and abnormal chromosome number.

 

Laboratory evaluation of myelodysplastic syndrome

  •  Anemia with variable MCV (normal or increased): At least 80% of patients with MDS are anemic at diagnosis.
  • Reduced erythrocyte count (in relation to the degree of anemia).
  • Hypogranular or agranular neutrophils; 40% of patients with MDS are neutropenic at diagnosis.
  • Normal or decreased platelet count. Thrombocytopenia complicates 30% to 45% of cases.
  • Bone marrow aspirate and biopsy with iron stain and cytogenetic studies: hypercellular bone marrow, with frequent clonal chromosomal abnormalities.
  • Additional lab studies include reticulocyte count, serum erythropoietin level (obtained before RBC transfusion), iron studies (ferritin, serum iron, TIBC), serum vitamin B12 level, RBC folate, HLA antigen typing and CMV testing (if hematopoietic stem cell transplantation is considered), paroxysmal nocturnal hemoglobinopathy screening by flow cytometry and HLA DR-15 typing (in hypoplastic anemia), HIV (in patient with risk factors).

Treatment of myelodysplastic syndrome

  • Results of chemotherapy are generally disappointing. Combination chemotherapy regimens (e.g., cytarabine plus doxorubicin) generally induce a complete response in only a minority of patients, and the average duration of response is less than 1 year.
  • Azacitidine (Vidaza), a pyrimidine nucleoside analogue of cytidine, recently US Food and Drug Administration (FDA)-approved for MDS, has been shown to improve the quality of life for patients with myelodysplastic syndrome and probably prolongs survival.
  • The role of myeloid growth factors (GCSF, GM-CSF) and immunotherapy is undefined. In a recent trial, 34% of patients treated with antithymocyte globulin (40 mg/kg for 4 days) became transfusion independent. Response was also associated with a statistically significantly longer survival.
  • Lenalidomide (Revlimid), a novel analogue of thalidomide, has demonstrated hematologic activity in patients with low-rise myelodysplastic syndrome who have no response to erythropoietin or who are unlikely to benefit from conventional therapy.
  • Monitor for infections, bleeding, and complications of anemia. Supportive measures include blood transfusions (with leukoreduced RBCs to minimize transfusion reactions and alloimmunization) and erythropoietin for anemia, and antibiotics to treat opportunistic infections. Iron overload from frequent transfusions may require iron chelation therapy with deferasirox. The optimal time to begin iron chelation to try to prevent hemosiderosis-associated organ dysfunction is unclear. If the patient’s life expectancy is greater than 1 year, chelation may be started after 25 to 30 U of RBCs have been transfused.
  • In younger age  Allogeneic stem-cell transplantation should be considered, healthier patients with International Prognostic Scoring System (IPSS) INT-2/high-risk MDS or secondary MDS who have an HLA-matched sibling donor.

The prognosis  of myelodysplastic syndrome

  • Cure rates in young patients with allogeneic bone marrow transplantation approach 30% to 50%.
  • The risk for transformation to AML varies with the percentage of blasts in the bone marrow. Table 7-5 describes the IPSS for MDS.
  • Nearly 50% of deaths from MDS are due to cytopenia associated with bone marrow failure.
  • The 1997 International Prognosis Scoring System (IPSS) uses the following three elements for staging.
  1. The proportion of myeloblasts in the patient’s marrow.
  2. The number of blood cell lineage deficits.
  3. The type of chromosomal abnormality present (e.g., poor risk includes abnormalities of chromosome 7, good risk includes clonal loss of the Y chromosome). According to the International Myelodysplastic Syndrome Risk Analysis Workshop, the most important variables in disease outcome are the specific cytogenetic abnormalities, the percentage of blasts in the bone marrow, and the number of hematopoietic lineages involved in the cytopenias.

Table 7-5   – International Prognostic Scoring System for MDS

  Score Value
Prognostic Variable 0 0.5 1.0 1.5 2
Bone marrow blasts (%) <5 5–10 11–21 21–30
Karyotype Good Intermediate Poor
Cytopenias 0 or 1 2 or 3

 

 

 

Conclusion

          Myelodysplastic  syndrome  is disease with low prognosis because of low blood count leads to infection as well as many complications. So it is important to treat the etiology for the good prognosis.   We will be expanding on this important topic in future articles. While I recommend you to register to download an e-book: “Adult Prevention Guide” for better health, a FREE.

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The Team Manager Web Diseases

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