![]() ![]() Although it used to be the case that test results would take a few days to return, the development of a new generation of automated clinical viscometers means that results can now be obtained within minutes, allowing accurate diagnosis and more targeted therapy. Those with myeloma will typically display a rouleaux formation on a peripheral smear and a large globulin gap, indicative of a significant paraprotein load. Patients will also have evidence of their underlying disorder. Normal plasma viscosity is between 1.4 and 1.8 centipoise while symptoms from hyperviscosity typically occur greater than 4 centipoise (about 4 times more viscous than water) and require emergency treatment. Diagnosis Īlthough elevated whole blood viscosity is a better measure of hyperviscosity and more common and clinically important, serum viscosity and plasma viscosity are more frequently measured. May occur with a white blood cell count greater than 100,000/mm 3 (100×10 9/L). 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). Types of hyperviscosity syndromes vary by pathology including serum hyperviscosity, which may cause neurologic or ocular disorders polycythemic hyperviscosity, which results in reduced blood flow or capillary perfusion and increased organ congestion and syndromes of hyperviscosity, caused by reduced deformability of red blood cells, often evident in sickle cell anemia. Hyperviscosity occurs from pathologic changes of either cellular or protein fractions of the blood such as is found in polycythemias, multiple myeloma (particularly IgA and IgG3), leukemia, monoclonal gammopathies such as Waldenström macroglobulinemia, sickle cell anemia, and sepsis. 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 is a group of symptoms triggered by an increase in the viscosity of the blood. This will lead to decreased oxygen delivery.Medical condition Hyperviscosity syndrome When the hematocrit rises to 60 or 70, which it often does in polycythemia, the blood viscosity can become as great as 10 times that of water, and its flow through blood vessels is greatly retarded because of increased resistance to flow. The viscosity of blood after this shear rate is reached is about five times as great as the viscosity of water. Until this point is reached the term viscosity cannot be applied to blood. The fluid must reach a shear rate of about 100 to be assumed Newtonian. However, plasma can be considered a Newtonian fluid, but blood cannot due to the red blood cells which add non-idealties to the fluid. The viscosity of blood thus depends on the viscosity of the plasma, in combination with the hematocrit. Physicians also may prescribe medicine for this conditions, including stroke, impotence, male infertility, Raynaud's disease, and nerve and circulation problems caused by diabetes.īlood is a liquid that consists of plasma and particles, such as the red blood cells. Viscous Blood can cause painful leg cramps or leg pain caused by poor circulation, a condition called intermittent claudication. Blood viscosity also increases with increases in red cell aggregability.įreebase Rate this definition: 5.0 / 1 voteīlood viscosity is a measure of the resistance of blood to flow, which is being deformed by either shear or extensional strain. Contrarily, blood viscosity increases when shear rate goes down with increased vessel diameters or with low flow, such as downstream from an obstruction or in diastole. Therefore, blood is a shear-thinning fluid. Blood becomes less viscous at high shear rates like those experienced with increased flow such as during exercise or in peak-systole. As such, the viscosity of blood varies with shear rate. Because of that, blood behaves as a non-Newtonian fluid. Red blood cells have unique mechanical behavior, which can be discussed under the terms erythrocyte deformability and erythrocyte aggregation. Blood viscosity is determined by plasma viscosity, hematocrit (volume fraction of red blood cell, which constitute 99.9% of the cellular elements) and mechanical properties of red blood cells. Alterations of these properties play significant roles in disease processes. Proper tissue perfusion can occur only when blood's rheological properties are within certain levels. Hemorheology, also spelled haemorheology (from Greek ‘αἷμα, haima 'blood' and rheology, from Greek ῥέω rhéō, 'flow' and -λoγία, -logia 'study of'), or blood rheology, is the study of flow properties of blood and its elements of plasma and cells. Wikipedia Rate this definition: 0.0 / 0 votes ![]()
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