ABSTRACT
Hypergammaglobulinemia increases serum viscosity and is the most common cause of hyperviscosity
syndrome. Monoclonal hypergammaglobulinemia resulting in hyperviscosity syndrome is
seen in multiple myeloma and Waldenström's macroglobulinemia. The reasons for elevated
viscosity are increased protein content and large molecular size, abnormal polymerization,
and abnormal shape of immunoglobulin molecules. Other hematologic and metabolic abnormalities
seen in patients with plasma cell dyscrasias also contribute to hyperviscosity. Symptomatic
hyperviscosity is much more common in Waldenström's macroglobulinemia (10 to 30%)
than it is in myeloma (2 to 6%). Symptoms of hyperviscosity usually appear when the
normal serum viscosity of 1.4 to 1.8 cp reaches 4 to 5 cp, corresponding to a serum
immunoglobulin M (IgM) level of at least 3 g/dL, an IgG level of 4 g/dL, and an IgA
level of 6 g/dL. Symptoms of hyperviscosity include constitutional symptoms; bleeding;
and ocular, neurological, and cardiovascular manifestations. Immediate therapy of
symptomatic hyperviscosity is directed at reduction of blood viscosity by plasmapheresis
to control symptoms. Long-term management is directed at control of the underlying
disease to prevent production of the monoclonal protein. There may be a small proportion
of individuals, usually old or with severely compromised performance status, who undergo
plasma exchange as the sole symptomatic therapy of hyperviscosity secondary to plasma
cell dyscrasia.
KEYWORDS
Hyperviscosity - gammaglobulin - macroglobulinemia - myeloma
