Ethrocytosis Essay

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Erythrocytosis/Polycythemia A. What Is Erythrocytosis? Erythrocytosis is defined as an excess of erythrocytes, or red blood cells (RBCs). RBCs carry oxygen to the body. When RBC levels are low, the body’s tissues cannot obtain enough oxygen. RBCs in the blood are measured by the hematocrit (the percentage of the blood volume made up of RBCs) or by the hemoglobin (the essential oxygen-carrying protein in the RBC). Erythrocytosis occurs if either of these values is elevated. The normal limits on these blood values for males and females respectively are 52% and 47% for the hematocrit, and 17.7 g/dl and 15.7 g/dl for hemoglobin concentration. B. Causes and Risk Factors There are several different kinds of erythrocytosis, and each has its own set of causes and risk factors. Relative Polycythemia. Some patients appear to have an excess of RBCs due to a loss of volume in the liquid portion of the blood, the plasma. This may be due to dehydration, diuretics (substances causing an increased loss of water through the urine, such as caffeine), burns, stress, and high blood pressure. Primary polycythemia, or polycythemia vera. Primary polycythemia is a myeloproliferative disorder in which the RBC count increases without being stimulated by the red blood cell stimulating hormone, erythropoietin (EPO). For more on this disorder, please see Myeloproliferative Disorders. Secondary polycythemia. In secondary polycythemia, the increase in RBC counts is due to an increase in the RBC stimulating hormone, EPO. Potential causes of this include: low blood oxygen, caused by heart disease or high altitude; continual exposure to carbon monoxide (heavy smoking of cigars or cigarettes); congenital (hereditary) disorders producing an abnormal hemoglobin or an overproduction of EPO; and diseases such as kidney disease. C. Signs and Symptoms Symptoms include: easy bruisability, purpura (purplish
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