myelosuppression

Myelosuppression is a reduction in bone marrow activity that leads to decreased production of blood cells. It most commonly results from cancer therapies such as cytotoxic chemotherapy and radiotherapy, but can also occur with bone marrow disorders, immune-mediated processes, toxins, infections, or after stem cell transplantation. The condition can cause pancytopenia (reduced red cells, white cells, and platelets) or isolated cytopenias in one lineage.

Pathophysiology involves injury to hematopoietic stem and progenitor cells or disruption of the marrow microenvironment, impairing erythropoiesis, leukopoiesis, and thrombopoiesis. Clinically, patients may experience fatigue and pallor from anemia; increased susceptibility to infections from neutropenia; and abnormal bleeding or bruising from thrombocytopenia. The nadir, or lowest blood counts, typically occurs after cytotoxic treatment and recovery follows over days to weeks, depending on the regimen and marrow reserve.

Diagnosis relies on blood tests showing cytopenias: low hemoglobin, reduced white blood cell count with neutropenia, and/or low platelets. Reticulocyte counts aid assessment of bone marrow response, and bone marrow examination may be indicated to distinguish myelodysplastic processes or aplastic anemia.

Management focuses on preventing complications and allowing marrow recovery. Supportive care includes transfusions for symptomatic anemia or severe thrombocytopenia, and growth factors such as G-CSF or GM-CSF to shorten neutropenia in selected patients. Infection prophylaxis and prompt treatment for febrile neutropenia are critical. Chemotherapy or radiotherapy schedules may be modified to reduce intensity. Prognosis depends on the underlying disease, the degree of cytopenias, and the patient’s marrow reserve.