Polyzythämie

Polyzythämie, also known as polycythemia or erythrocytosis, is a medical condition characterized by an abnormal increase in the concentration of red blood cells in the blood. This increase can lead to a thickening of the blood, a condition known as hyperviscosity, which can impede blood flow and increase the risk of blood clots, stroke, and heart attack.

There are two main types of polycythämie: primary and secondary. Primary polycythämie, also known as polycythemia vera, is a myeloproliferative neoplasm where the bone marrow produces too many red blood cells, often along with white blood cells and platelets. Secondary polycythämie occurs when the body produces more red blood cells in response to a reduced oxygen level in the blood, such as due to lung disease, high altitude living, or certain tumors that produce erythropoietin, a hormone that stimulates red blood cell production.

Symptoms of polycythämie can vary depending on the severity and type, and may include headache, dizziness, itching, shortness of breath, and a reddish complexion. Diagnosis typically involves blood tests to measure red blood cell count, hemoglobin, and hematocrit. Treatment aims to reduce the red blood cell count and manage symptoms, and may include phlebotomy (bloodletting), medications to suppress bone marrow activity, or treating the underlying cause in the case of secondary polycythämie.