Essential thrombocythemia is a chronic disease common in people over age 50 and slightly more common in women. Young people can develop it as well. It is characterised by the overproduction of platelets by megakaryocytes in the bone marrow. Essential thrombocythemia is an uncommon disorder where the body produces too many blood platelets. This condition may cause to feel fatigued, lightheaded and to experience headaches and vision changes. It also increases the risk of blood clots.
The greatest health risk in patients with ET is an increased risk of developing blood clots. Blood clots can be in the deep vessels of the legs or lungs; ET patients are also more likely to experience strokes and heart attacks. ET patients can develop clots elsewhere, including within the abdomen, an otherwise rare site for clots to form. The risk of clotting increases with age, and disease-associated risks may be quite different for children than for adults, with children generally being at low risk for clots and other problems related to ET.
The 15-year survival was 65% in patients with polycythemia and 73% in those with thrombocythemia. By Cox regression analysis, the independent predictors of death were a history of thrombosis for polycythemia (hazard ratio [HR] = 2.2; P = 0.0002) and thrombocythemia (HR = 2; P = 0.01), and male sex (HR = 1.8; P = 0.03) for thrombocythemia. Mortality compared with the general population was 1.6-fold higher (P <0.001) in patients with polycythemia but was not increased in those with thrombocythemia (SMR = 1; P = 0.8)