A prospective study of 9 patients with plasma cell dyscrasia was performed to 
evaluate the need of plasma exchange (PE) and its possible effect in the acute 
and chronic management of hyperviscosity syndrome. The underlying dyscrasia was 
an IgG myeloma in 5 cases, IgA myeloma in 2 cases, one patient had IgD myeloma 
and in one patient Waldemström's macroglobulinemia was diagnosed. The main 
sequelae of circulatory disturbances, caused by increased blood resistance to 
flow, were fundus alterations (55.6%), neurologic manifestations (88.9%), a 
tendency to bleeding (44.4%) and renal failure (55.6%). In total, 49 PE 
procedures were performed. Following PE, hyperviscosity symptoms improved in 
88.9% of the treated patients. The improvement in neurologic manifestations and 
hematologic complications was very fast, within the first PE session. The effect 
was less evident in ocular fundus alterations. Only one myeloma patient 
developed chronic renal failure. PE is the most effective method in the 
treatment of hyperviscosity syndrome often seen with multiple myeloma and 
Waldenström's macroglobulinemia, and it is therapy of choice for this 
complication.