Treatment Of Hyperviscosity Syndrome

PLASMA EXCHANGE/PLASMAPHERESIS

Plasmapheresis can be successfully used as an emergent therapy for patients with immunoglobulin-related HVS. Typically, two to four courses of plasmapheresis are required to achieve symptomatic control. However, marked improvement in HVS can occur even after the first course of plasmapheresis. The benefit of plasma-pheresis usually lasts 4-6 weeks in patients with immunoglobulin-related HVS, and should be considered a temporizing measure until definitive therapy can be initiated to control disease.44 Plasmapheresis can also be effective in reverting HV-associated retinopathy.28'30'45'46 Improvements in renal function after plasmapheresis have also been reported in patients with hyperviscosity-related renal failure.43

In general, the response of patients to plasmaphere-sis depends on three main factors: (1) the intravascular component of the protein; (2) the volume exchanged; and (3) the synthesis rate of the protein being removed. The IgM molecule is large, with 70-95% localized in the intravascular compartment. A single plasma exchange can result in a reduction in serum IgM by 35%, with a concomitant decrease of 50-60% in serum viscosity.47 In contrast to IgM, only 40% of IgG and IgA immunoglobulins are intravascular. Therefore, plasmapheresis is more likely to be successful in patients with WM, as opposed to multiple myeloma. There is no evidence that regular removal of monoclonal proteins accelerates or reduces their rate of synthesis. Concurrent systemic chemotherapy is therefore required for long-term management. However, plasmapheresis may be rarely indicated on a long-term basis in patients with hyperviscosity who are drug resistant or whose only clinical problem is due to the

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