erythrocythemia

Erythrocythemia, also known as polycythemia or erythrocytosis, is a condition characterized by an abnormal increase in the number of red blood cells and hemoglobin in the blood. This increase thickens the blood, slows its flow, and raises the risk of clot formation within the circulatory system.12

Polycythemia can be relative, occurring due to a loss of blood plasma, or absolute, indicating an increase in the total mass of red blood cells. It often develops in response to a higher demand for oxygen. This can happen at high altitudes due to decreased atmospheric pressure, or with impaired lung function from conditions like emphysema or extreme obesity. Congenital heart disorders that affect blood oxygenation and certain hemoglobin defects can also lead to polycythemia.12

A distinct condition is polycythemia vera, where excess red blood cells are produced without a known cause. This often involves an increase in white blood cells and platelets, and an enlarged spleen. Treatment for polycythemia typically aims to reduce red blood cell volume, often through blood removal or, in some cases, medication or radiation therapy.2