Classification and external resources
Polycythemia (or polycythaemia or erythrocytosis) is a condition in which there is a net increase in the total number of blood cells, primarily red blood cells, in the body. The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify Diseases The International Statistical Classification of Diseases and Related Health Problems 10th Revision ( ICD -10) is a coding of diseases and signs symptoms abnormal findings P00-P96 - Certain conditions originating in the Perinatal period (P00-P04 Fetus and newborn affected by maternal factors and by complications of pregnancy labour and The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify Diseases The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. The Diseases Database is a free Website that provides information about the relationships between medical conditions Symptoms, and Medications. Medical Subject Headings ( MeSH) is a huge Controlled vocabulary (or metadata system for the purpose of indexing journal articles and books A blood cell (also called blood corpuscle) is any cell of any type normally found in Blood. Red blood cells are the most common type of Blood cell and the Vertebrate body's principal means of delivering Oxygen to the body tissues via the Blood  The overproduction of red blood cells may be due to a primary process in the bone marrow (a so-called myeloproliferative syndrome), or it may be a reaction to chronically low oxygen levels or, rarely, a malignancy. Bone marrow is the flexible tissue found in the hollow interior of Bones In adults marrow in large bones produces new Blood cells It constitutes 4% of The myeloproliferative diseases ("MPD"s are a group of diseases of the Bone marrow in which excess cells are produced Chronic Hypoxia is a pathological condition in which the body as a whole ( generalized hypoxia) or region of the body ( tissue hypoxia) is deprived of adequate Cancer (medical term Malignant Neoplasm) is a class of Diseases in which a group of cells display uncontrolled
Primary polycythemia, often called polycythemia vera (PCV), polycythemia rubra vera (PRV), or erythremia, occurs when excess red blood cells are produced as a result of an abnormality of the bone marrow. Primary Polycythemia, often called Polycythemia vera (PCV polycythemia rubra vera (PRV or erythremia occurs when excess red blood cells are produced Primary Polycythemia, often called Polycythemia vera (PCV polycythemia rubra vera (PRV or erythremia occurs when excess red blood cells are produced Bone marrow is the flexible tissue found in the hollow interior of Bones In adults marrow in large bones produces new Blood cells It constitutes 4% of Often, excess white blood cells and platelets are also produced. Platelets, or Thrombocytes, are small cytoplasmic bodies derived from cells They circulate in the Blood of Mammals and are involved Polycythemia vera is classified as a myeloproliferative disease. The myeloproliferative diseases ("MPD"s are a group of diseases of the Bone marrow in which excess cells are produced Symptoms include headaches, vertigo, and an abnormally enlarged spleen and/or liver. Vertigo (from the Latin vertere, to turn and the suffix -igo, a condition i Splenomegaly is an enlargement of the Spleen, which usually lies in the left upper quadrant (LUQ of the Human abdomen. Hepatomegaly is the condition of having an enlarged Liver. It is a nonspecific medical sign having many causes which can broadly be broken down into Infection In some cases, affected individuals may have associated conditions including high blood pressure or the formation of blood clots. Hypertension, also referred to as high blood pressure, HTN or HPN, is a medical condition in which the Blood pressure is chronically elevated Thrombosis is the formation of a blood Clot ( Thrombus) inside a Blood vessel, obstructing the flow of Blood through the Circulatory Transformation to acute leukemia is rare. Leukemia or leukaemia (Greek leukos λευκός, "white" aima αίμα, "blood" is a Cancer of the Blood Phlebotomy is the mainstay of treatment. A hallmark of polycythemia is an elevated hematocrit, with Hct > 55% seen in 83% of cases.  Mutations in JAK2 are found in 95% of cases, though also present in other myeloproliferative disorders. 
Secondary polycythemia is caused by either natural or artificial increases in the production of erythropoietin, hence an increased production of erythrocytes. Erythropoietin (ɨˌɹɪθɹoʊˈpɔɪɨtɨn /ɨˌɹɪθɹoʊˈpɔɪtən/ or /ɨˌɹiːθɹoʊ-/ or EPO is a Glycoprotein Hormone that controls In secondary polycythemia, there may be 6 to 8 million and occasionally 9 million erythrocytes per cubic millimeter (milliliter) of blood. Secondary polycythemia resolves when the underlying cause is treated.
Secondary polycythemia in which the production of erythropoietin increases appropriately is called physiologic polycythemia. This physiologic (meaning normal) polycythemia is a normal adaptation to living at high altitudes (see altitude sickness). Altitude sickness, also known as acute mountain sickness ( AMS) altitude illness, or soroche, is a pathological condition that is caused by acute Many athletes train at high altitude to take advantage of this effect — a legal form of blood doping. Blood doping is the practice of boosting the number of Red blood cells (RBCs in the circulation in order to enhance athletic performance Similarly, athletes with primary polycythemia may have a competitive advantage due to greater stamina.
Other causes of secondary polycythemia include smoking, renal or liver tumors, heart or lung diseases that result in hypoxia, and endocrine abnormalities including pheochromocytoma and adrenal adenoma with Cushing's syndrome. Chronic Hypoxia is a pathological condition in which the body as a whole ( generalized hypoxia) or region of the body ( tissue hypoxia) is deprived of adequate A phaeochromocytoma ( pheochromocytoma in the US is a Neuroendocrine tumor of the medulla of the Adrenal glands (originating in the Chromaffin An adenoma is a collection of growths (-oma of glandular origin Athletes and bodybuilders who use anabolic steroids or erythropoietin may develop secondary polycythemia. Anabolic steroids, or anabolic-androgenic steroids ( AAS) are a class of Steroid hormones related to the hormone Testosterone.
Secondary polycythemia can be induced directly by phlebotomy to withdraw some blood, concentrate the erythrocytes, and return them to the body.
Chuvash polycythemia refers to a familial form of erythrocytosis different than classical polycythemia vera. This involved patients from Chuvashia and is associated with a C598T mutation in the von Hippel-Lindau gene (VHL). Von Hippel-Lindau disease (VHL is a rare inherited Genetic condition involving the abnormal growth of Tumors in parts of the body which are particularly A cluster of patients with Chuvash polycythemia have been found in other populations, such as on the Italian island of Ischia, located in the Bay of Naples.
Relative polycythemia is an apparent rise of the erythrocyte level in the blood; however, the underlying cause is reduced blood plasma. Relative polycythemia is often caused by loss of body fluids, such as through burns, dehydration and stress. Bodily fluids listed below are found in the bodies of men and/or women