Remember Waldenström's macroglobulinaemia as a rare cause of a increased ESR.
In most cases a long-term disease; progression may be very slow
Basically a lymphoma disease (lymphoplasmacytic lymphoma); defined as WM when paraprotein of IgM class is detected
Clinical picture is characterized by symptoms of cytopenias and immunodeficiency, by extramedullary tumour infiltrates and by hyperviscosity symptoms, often neuropathy.
No osteolytic lesions
Definition
Clonal proliferation of mature B cells (differentiation at the lymphocyte-plasma cell level) with a homogeneous immunoglobulin fraction (paraprotein, M component) detected in serum protein electrophoresis. This always consists of IgM.
Epidemiology
Far less frequent than myeloma, incidence about 0.3 new cases/100 000 persons/year
Usually occurs in persons aged 60-70 years, very rare in younger persons.
Slightly more common in men (60% of the cases).
Aetiology
Unknown; an association of chronic immunostimulation and autoimmune diseases with the disease onset has been suspected.
Diagnostic criteria
Lymphoplasmacytic lymphoma as a finding in the bone marrow and a serum IgM paraprotein.
Differential diagnosis
Other conditions with IgM paraprotein:
IgM-MGUS (monoclonal IgM-gammopathy of undetermined significance, drawing the line between IgM-MGUS and WM is difficult)
Extremely rare IgM myeloma (osteolytic bone lesions suggest myeloma)
Paraprotein in serum protein electrophoresis which in immunofixation is typed as IgM
Increased serum viscosity can be detected in about 50% of the patients, if IgM > 40 g/l (the investigation is rarely needed in follow-up, obtaining the result involves a delay).
Often anaemia or thrombocytopenia
High paraprotein concentration may cause erratic laboratory test results (e.g. sodium, creatinine, urea, cholesterol, bilirubin, LD, CRP).
Primary investigations
Complete automated blood count and bone marrow aspiration
Serum protein electrophoresis (immunofixation should be performed if paraprotein is detected)
Plasma IgG, IgA and IgM
Plasma creatinine and serum urate
Chest x-ray and upper abdominal ultrasonography
Course of the disease and prognosis
The course of the disease varies greatly; the average life expectancy is 5-6 years. Good response to therapy improves the prognosis.
WM usually is a long-lasting disease and its progression may be very slow.