Myelodysplastic Syndromes (MDS)

Myelodysplastic syndromes (MDS) are a group of clonal hematopoietic stem cell disorders characterized by ineffective hematopoiesis, morphological dysplasia in one or more myeloid cell lines, and a risk of transformation to acute myeloid leukemia (approximately 30% of cases). The pathogenesis involves acquired somatic mutations in hematopoietic stem cells (commonly involving splicing factors SF3B1, epigenetic regulators TET2, DNMT3A, and tumor suppressors TP53) that cause abnormal differentiation and increased apoptosis of developing blood cells in the bone marrow. Despite a hypercellular marrow, peripheral blood shows cytopenias: anemia (fatigue, dyspnea), neutropenia (infection risk), and thrombocytopenia (bleeding risk). The bone marrow shows characteristic dysplastic features: ringed sideroblasts, hypolobulated neutrophils (pseudo-Pelger-Huet anomaly), and micromegakaryocytes. The nurse monitors CBC for worsening cytopenias, assesses for signs of infection in neutropenic patients, implements bleeding precautions, administers red blood cell and platelet transfusions as prescribed, monitors for iron overload from chronic transfusions (serum ferritin), administers iron chelation therapy, administers hypomethylating agents (azacitidine, decitabine) and monitors for side effects, and educates patients about the chronic nature of the disease and signs of leukemic transformation.