blood disorders
Secondary Erythrocytosis
Introduction
Erythrocytosis is increased production of red blood cells (erythrocytes). (See also Overview of Myeloproliferative Neoplasms .) Erythrocytosis may be Primary: Caused by a disorder of the Formation of Blood Cells None Secondary: Caused by a disorder that triggers increased production by normal blood-forming cells occurs as a result of Polycythemia Vera , a Secondary erythrocytosisdevelops generally as a result of a disorder that increaseserythropoietinsecretion.Erythropoietinis a hormone made in the kidneys that stimulates the bone marrow to produce red blood cells. As such, secondary erythrocytosis is not considered a myeloproliferative neoplasm. However, it is important for doctors to look for it because both primary and secondary erythrocytosis result in too many red blood cells. Secondary erythrocytosis has many causes. It can be caused by oxygen deprivation, which can result, for example, from Smoking Severe lung disease, such as Chronic Obstructive Pulmonary Disease (COPD) (chronic obstructive pulmonary disease) Overview of Heart Defects None Carbon Monoxide Poisoning None Altitude Illness None ). In some Overview of Heart Defects , blood is misdirected away from the heart so that it cannot pick up oxygen, causing hypoxia (a low level of oxygen in the blood) and resulting in secondary erythrocytosis. Other causes of secondary erythrocytosis include Treatment with male hormones such astestosterone Kidney problems, including tumors, cysts, and narrowing of the arteries that go to the kidneys Tumors of the liver, brain, or adrenal gland Genetic disorders that affecterythropoietinproduction (congenital erythrocytosis) Male hormones such astestosteronestimulate production oferythropoietin. Problems that decrease blood flow to the kidneys such as tumors, cysts, and narrowing of the arteries that go to the kidneys increaseerythropoietinsecretion. Tumor-associated erythrocytosiscan occur when certain tumors or cysts, such as of the kidneys, liver, brain, or uterus secreteerythropoietin. Congenital erythrocytosisis present at birth and is usually caused by an inherited genetic disorder that affects the affinity of hemoglobin for oxygen or the response to hypoxia. (Hemoglobin is the molecule that carries oxygen within red blood cells. Hypoxia is when the level of oxygen in the blood is low.) These inherited genetic disorders are rare, but they are suspected when a person with erythrocytosis has family members who are also affected. Inrelative erythrocytosis,there are not any extra red blood cells, but red blood cells seem to be at a high concentration because there is less fluid (plasma) in the bloodstream. The low plasma level can result from burns, vomiting, diarrhea, drinking an inadequate amount of fluids, or the use of medications that speed elimination of salt and water by the kidneys (diuretics). 