Hyperviscosity syndrome

Hyperviscosity syndrome is a group of symptoms triggered by increase in the viscosity of the blood. Symptoms of high blood viscosity include spontaneous bleeding from mucous membranes, visual disturbances due to retinopathy, and neurologic symptoms ranging from headache and vertigo to seizures and coma.

Hyperviscosity syndrome may be caused by an increase in serum proteins or cells. Increased levels of proteins are seen with monoclonal gammopathies such as Waldenström macroglobulinemia and in multiple myeloma (particularly IgA and IgG3). High cell counts are seen in conditions such as polycythemia (raised red blood cells) or leukemia (more white blood cells, especially in acute leukemic blast crises).

Diagnosis

Serum viscosity can be measured. Normal is between 1.4 and 1.8 centipoises but to have symptoms from hyperviscosity, 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 hyperviscosity 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

• MedlinePlus Encyclopedia 000536 - "Hyperviscosity - newborn"
• 1134166044 at GPnotebook