Waldenström Macroglobulinemia

Waldenström macroglobulinemia (WM) is an indolent lymphoplasmacytic lymphoma. Abnormal B cells and plasma-cell-like cells infiltrate the bone marrow and secrete one type of immunoglobulin: monoclonal IgM. Marrow infiltration can suppress normal blood-cell production, leading to anemia and other cytopenias. The circulating IgM creates a separate problem. Because IgM is a large pentameric protein, a high concentration can increase serum viscosity, slow microcirculatory flow, and impair oxygen delivery to tissues. The result is hyperviscosity syndrome, the complication that most rapidly changes nursing priority. IgM-related immune activity can also injure peripheral nerves, producing numbness, tingling, burning pain, or distal weakness. These neurologic findings may reflect the disease itself rather than hyperviscosity, so the nurse clarifies whether symptoms are chronic and length-dependent or new, rapidly progressive, and accompanied by headache, visual change, or altered cognition. An elevated IgM level by itself does not establish WM and does not automatically mean that the patient has an emergency. The clinical picture, marrow findings, and symptoms must be interpreted together.