What does polycythaemia mean?
Polycythaemia is a condition in which the number of red blood cells in the blood is abnormally high. This can make the blood thicker and increase the work required of the heart, sometimes producing symptoms such as headaches, dizziness, fatigue, or flushed skin. The increase may be secondary: living at high altitude, smoking, chronic lung disease, or certain kidney conditions can prompt the body to produce additional red blood cells. Polycythaemia vera is a distinct disorder caused by abnormal bone-marrow cell growth. The word is clinically important because identifying the type and underlying cause helps doctors assess cardiovascular risk and decide whether treatment is necessary. In British English it is written “polycythaemia”; American English normally uses “polycythemia.”
nounAn abnormal increase in the number of red blood cells in the blood, which can make it thicker and increase the strain on the heart and circulation. It may be a response to factors such as living at high altitude or an underlying disorder such as polycythaemia vera.
- An abnormal increase in the number of red blood cells in the blood, with possible increased blood viscosity and strain on the cardiovascular system.
"Her doctor diagnosed secondary polycythaemia after prolonged exposure to high altitude."
"Routine blood tests revealed polycythaemia, so further investigation was needed to determine its cause."
"Polycythaemia vera is a chronic blood disorder in which the bone marrow produces too many red blood cells."
The plural is rarely used because the name of the condition is normally treated as singular.
"Polycythaemias were identified in several members of the expedition."
At high altitude, more red blood cells can be a normal adaptation; polycythaemia becomes a medical concern when the increase is excessive or unexplained.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does polycythaemia come from?
The word was formed in the 19th century from Greek elements meaning “many” and “blood cells.” Its “-aemia” component comes from Greek haima, meaning “blood,” within words formed on the model of anaemia. The related terms anaemia and leukaemia likewise combine Greek roots concerning blood with different descriptive prefixes.
Related word forms
How polycythaemia is actually used
The British spelling is “polycythaemia”; the American spelling is “polycythemia.” The British adjective is “polycythaemic,” while the American adjective is “polycythemic.” The condition should not be confused with the normal physiological increase in red blood cells that can occur at high altitude.
Easily confused with polycythaemia
Polycythemia is the standard American spelling of polycythaemia and refers to the same medical condition.