Waldenström’s Macroglobulinemia: Correlation Between Expanded Plasma Volume and Increased Serum Viscosity

In 17 patients with Waldenström’s Macroglobulinemia, total chromium space, red cell mass, plasma volume and relative serum viscosities were determined; aldosterone excretion was determined in 12. Ten of the 15 patients who manifested elevated serum viscosity at some time during the course of study presented signs and symptoms of hyperviscosity syndrome. All patients had increased total blood volume. Fifteen had moderate decreases in red cell mass but all had elevations of plasma volume far in excess of that required to compensate for the lowered cell mass. The degree of the increase in plasma volume correlated (r = 0.74) with the degree of abnormality in relative serum viscosity. Aldosterone excretion in such patients was normal to low. It is concluded that the plasma volume increase is correlated with serum viscosity and is mediated by sodium retention mechanisms not involving modification of aldosterone secretion.