Tulane University Medical Center (Definition)
Polycythemia vera is a clonal stem cell disorder characterized by excessive erythrocyte production. Its etiology is not fully established, but hypersensitivity to interleukin-3 may play a role in the sustained erythrocytosis observed in this disease.
Polycythemia vera usually occurs within the age range of 20-80, with 60 being the mean age of onset. The disease is slightly more common in males than in females. Clinical features include headaches, weakness, weight loss, and pruritus (itching without visible eruption on the skin). 10-15 % of patients may also present with gout due to hyperuricemia. Hemorrhage, thrombosis and hyperviscosity may be evident at any time. Splenomegaly, as a result of vascular congestion, is seen in 75% of patients at the time of presentation. Hepatomegaly is observed in about 30% of cases