Definitions

hyperviscosity

Hyperviscosity syndrome

Hyperviscosity syndrome is an increase in the viscosity of the blood. This may be caused by an increase in serum proteins and presents with spontaneous bleeding from mucous membranes, retinopathy and other visual disturbances, and neurologic symptoms ranging from headache and vertigo to seizures and coma. It is usually seen with monoclonal gammopathies such as Waldenström macroglobulinemia and in multiple myeloma (particularly IgA and IgG3). Hyperviscosity syndrome can also be seen in polycythemia and acute leukemic blast crises.

Diagnosis

Serum viscosity can be measured. Normal is between 1.4 and 1.8 centipoises but to have symptoms from hyperviscocity, serum viscosity is usually greater than 5 centipoises. Patients will also have evidence of their underlying disorder. Those with myeloma will typically display a rouleaux formation on a peripheral smear and a large globulin gap, indicative of a significant paraprotein load. While viscosity can be directly measured, results can take a few days to return and thus a high index of suspicion is required to make the diagnosis in a timely manner. If hyperviscocity is suspected, treatment may need to be started prior to obtaining the official viscosity level.

Treatment

Plasmapheresis may be used to decrease viscosity in the case of myeloma, whereas leukapheresis or phlebotomy may be employed in a leukemic or polycythemic crisis, respectively. Blood transfusions should be used with caution as they can increase serum viscosity. Hydration is a temporizing measure to employ while preparing pheresis. Even after treatment, the condition will recur unless the underlying disorder is treated.

External links

  • - "Hyperviscosity - newborn"

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