Slow blood flow throughout the body

As blood volume increases, blood viscosity increases, resulting in slow blood flow and ischemia of tissues throughout the body. Polycythemia vera (PV) is a myeloproliferative disease mainly due to clonal erythrocytosis. The clinical features are slow onset, long course of disease, red and purple skin and mucous membranes, hepatosplenomegaly with vascular and nervous system symptoms, markedly increased red blood cells, increased whole blood volume, often accompanied by total white blood cells and thrombocytosis.