Polycythemia
Introduction
Disease state in which the proportion of blood volume that is occupied by red blood cells increases
May be due to:
an increase in the mass of red blood cells ("absolute polycythemia")
a decrease in the volume of plasma ("relative polycythemia")
Absolute polycythemia
Primary polycythemia
Due to factors intrinsic to red cell precursors
Polycythemia vera (PCV)
Occurs when excess red blood cells are produced as a result of an abnormality of the bone marrow
Often, excess white blood cells and platelets are also produced
Classified as a myeloproliferative disease
Primary familial polycythemia, Primary familial and congenital polycythemia (PFCP)
Benign hereditary condition
Possibly due to a dominant mutation in the erythropoietin receptor
Secondary polycythemia
Caused by either natural or artificial increases in the production of erythropoietin
Called physiologic polycythemia if the increase is appropriate
Altitude related
Hypoxic disease associated
Genetic
Associated with abnormalities in hemoglobin oxygen release
Can also be pathological
Neoplasms
Renal or liver tumors, hemangioblastomas in the central nervous system
Endocrine abnormalities including pheochromocytoma and adrenal adenoma with Cushing's syndrome
People whose testosterone levels are high because of the use anabolic steroids
Polycythemia caused by altered oxygen sensing
Inherited mutations in genes which all result in increased stability of Hypoxia Inducible Factors (HIFs)
Chuvash polycythemia
PHD2 erythrocytosis
HIF2α erythrocytosis
Relative polycythemia
An apparent rise of the erythrocyte level in the blood
However, the underlying cause is reduced blood plasma
Causes:
Loss of body fluids, such as through burns, dehydration and stress
Can be caused by apparent polycythemia also known as Gaisböck's syndrome
Apparent polycythemia primarily affects middle-aged obese men
Associated with smoking, increased alcohol intake and hypertension.[13]