Hyperviscosity syndromes are a well-established class of conditions that can arise in a variety of disease states, including among others polycythemia vera, dysproteinemias, multiple myeloma, leukemia, sickle cell anemia, and sepsis.
Hyperviscosity includes syndromes of serum hyperviscosity where patients may hemorrhage or experience neurologic or ocular disorders; syndromes of polycythemic hyperviscosity that result in reduced blood flow or capillary perfusion and increased organ congestion; and, syndromes of hyperviscosity caused by reduced deformability of red blood cells as in sickle cell anemia.
Kwaan HC, Bongu A. The hyperviscosity syndromes. Semin Thromb Hemost 1999; 25:199-208.