by Leslie Owen Simpson(more info)
listed in cfs me, originally published in issue 169 - April 2010
The study of blood is shared between two branches of medical science, namely haematology and haemorheology (blood rheology). While haematology deals with the cellular and chemical make up of blood, haemorheology relates to those physical factors of the blood which influence the rate of blood flow, such as plasma viscosity, whole blood viscosity and red cell deformability. For unexplained reasons, blood rheology is not taught at medical schools, and medical students will not be made aware of the thixotropic nature of blood, i.e. that there is an inverse relationship between the rate of blood flow and blood viscosity. Thus the slower the rate of blood flow, the higher is the viscosity of the blood. As a result, general practitioners will not be aware of the clinical implications of altered blood rheology except for a small number of disorders in which increased blood viscosity is an accepted feature. Polycythemia rubra vera is a condition in which the number of red cells is increased greatly, and this is manifested as increased blood viscosity with a variety of dysfunctional features. But when the excess of red cells is removed, normal tissue function is restored. Myelomatosis is a condition in which the synthesis of myeloma protein increases blood viscosity. When the myeloma protein is removed by the use of plasmapheresis, normal rates of blood flow are restored.