Polycythemia Vera
Overview
Plain-Language Overview
Polycythemia Vera is a rare blood disorder that affects the bone marrow, the part of the body responsible for making blood cells. In this condition, the bone marrow produces too many red blood cells, which causes the blood to become thicker than normal. This thickened blood can slow down circulation and increase the risk of blood clots, which may lead to serious problems like strokes or heart attacks. People with Polycythemia Vera may experience symptoms such as headaches, dizziness, and a feeling of fullness in the abdomen due to an enlarged spleen. The disorder primarily involves the hematologic system and impacts overall blood flow and oxygen delivery to tissues. It is a chronic condition that requires medical evaluation and monitoring.
Clinical Definition
Polycythemia Vera is a chronic myeloproliferative neoplasm characterized by clonal proliferation of hematopoietic stem cells leading to excessive production of red blood cells, often accompanied by increased white blood cells and platelets. The disease is most commonly caused by a somatic mutation in the JAK2 gene, specifically the V617F mutation, which leads to constitutive activation of the JAK-STAT signaling pathway and uncontrolled cell growth. This results in increased blood viscosity and a heightened risk of thrombosis, which are major clinical concerns. Patients often present with symptoms related to hyperviscosity, such as pruritus after bathing, erythromelalgia, and splenomegaly. The disorder is significant due to its potential progression to myelofibrosis or acute leukemia. Diagnosis and management focus on controlling hematocrit levels and preventing thrombotic complications.