Coordinates | 45°30′″N73°40′″N |
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{{infobox disease | name | Polycythemia | Image Packed cell volume diagram.svg | Caption Packed cell volume diagram. | DiseasesDB 10295 | ICD10 , | ICD9 , | ICDO | OMIM | MedlinePlus | eMedicineSubj Ped | eMedicineTopic 1848 | MeshID D011086 | }} |
It can be due to an increase in the mass of red blood cells ("absolute polycythemia") or to a decrease in the volume of plasma ("relative polycythemia").
Primary familial polycythemia, Primary familial and congenital polycythemia (PFCP) also exists as a benign hereditary condition, in contrast with malignant acquired Polycythemia vera. In some of the cases a molecular mechanism of PFCP has been identified to be a dominant mutation in the erythropoietin receptor.
Secondary polycythemia in which the production of erythropoietin increases appropriately is called physiologic polycythemia.
Conditions which may result in a physiologically appropriate polycythemia include: Altitude related - This physiologic (meaning normal) polycythemia is a normal adaptation to living at high altitudes (see altitude sickness). Many athletes train at high altitude to take advantage of this effect — a legal form of blood doping. Some individuals believe athletes with primary polycythemia may have a competitive advantage due to greater stamina. However, this has yet to be proven due to the multifaceted complications associated with this condition.
Hypoxic disease associated - for example in cyanotic heart disease where blood oxygen levels are reduced significantly. May also occur as a result of hypoxic lung disease and as a result of chronic obstructive sleep apnea.
Iatrogenic - Secondary polycythemia can be induced directly by phlebotomy (blood letting) to withdraw some blood, concentrate the erythrocytes, and return them to the body.
Genetic - Heritable causes of secondary polycythemia also exist and are associated with abnormalities in hemoglobin oxygen release. Patients have a special form of hemoglobin known as Hb Chesaspeake, which has a greater inherent affinity for oxygen than normal adult hemoglobin. This reduces oxygen delivery to the kidneys, causing increased erythropoietin production and a resultant polycythemia. Hemoglobin Kempsey also produces a similar clinical picture. These conditions are relatively uncommon.
Conditions where the polycythemia is not as a result of physiologic adaptation and occurs irrespective of body needs include: Neoplasms - Renal or liver tumors, hemangioblastomas in the central nervous system, and endocrine abnormalities including pheochromocytoma and adrenal adenoma with Cushing's syndrome. People whose testosterone levels are high because of the use anabolic steroids, including athletes who abuse steroids and people whose doctors put them on doses that are too high, as well as people who take erythropoietin may develop secondary polycythemia. Polycythemia Vera is a condition that evidence suggests may be linked to radiation exposure. There are treatment options but no known cure. PV is characterized by an increase in the numbers of all types of blood cells which may reach a level of 80 - 90 on the hematocrit. Most, if not all, the blood cells are a produced by one abnormal hematopoietic stem cell. This condition usually affects individuals who are 60 – 80 years of age.***
Category:Red blood cell disorders Category:Haemorrhagic and haematological disorders of fetus and newborn Category:Hematopathology
ar:كثرة كريات الدم الحمر de:Polyglobulie et:Polütsüteemia es:Policitemia fr:Polyglobulie hr:Policitemija it:Policitemia nl:Polycythemie ja:多血症 pt:Poliglobulia fi:PolysytemiaThis text is licensed under the Creative Commons CC-BY-SA License. This text was originally published on Wikipedia and was developed by the Wikipedia community.
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