What is the Difference Between Polycythemia and Polycythemia Vera?

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Polycythemia and polycythemia vera are related but distinct conditions. Here are the key differences between the two:

  1. Definition: Polycythemia is a general term for all conditions that result in a high red blood cell count, whereas polycythemia vera is a specific subtype of polycythemia.
  2. Causes: Polycythemia can be triggered by either increased erythropoietin production or excessive division of hematopoietic stem cells, resulting in an increased red blood cell production. Polycythemia vera, on the other hand, is a rare blood disorder caused by an acquired genetic mutation in the Janus kinase 2 (JAK2) gene.
  3. Bone Marrow Activity: In polycythemia vera, bone marrow shows inherent increased proliferative activity, while secondary polycythemia is characterized by different causes of polycythemia/erythrocytosis.
  4. Cell Lines: Polycythemia vera can be associated with the overproduction of all three cell lines (red blood cells, white blood cells, and platelets), while secondary polycythemia may involve only red blood cells.
  5. Treatment: The treatment of secondary polycythemia is directed at correcting the cause, while polycythemia vera treatment modalities include phlebotomy, which is established as the backbone of therapy.

In summary, polycythemia vera is a specific type of polycythemia with a distinct cause, affecting multiple cell lines, and has a different treatment approach compared to other forms of polycythemia.

Comparative Table: Polycythemia vs Polycythemia Vera

Polycythemia and Polycythemia Vera are related but distinct conditions. Here is a table summarizing the differences between the two:

Feature Polycythemia Polycythemia Vera
Definition An increase in red cell count, hemoglobin, and PCV. A clonal stem cell disorder in which there is an alteration in the pluripotent myeloid and megakaryocytic progenitor cells.
Forms Absolute erythrocytosis (true increase in red cell volume) and relative erythrocytosis (decrease in plasma volume with a normal red cell volume). A specific form of polycythemia caused by genetic mutations, particularly the V617F mutation in the JAK2 kinase.
Causes Polycythemia can be caused by various factors, including chronic hypoxia in patients with chronic lung disorders. Polycythemia Vera is a chronic myeloproliferative disorder characterized by an increased red blood cell mass (erythrocytosis), which leads to hyperviscosity and an increased risk of thrombosis.
Symptoms Patients may present with complaints of pruritus after bathing, burning pains in the distal extremities (erythromelalgia), gastrointestinal disturbances, or nonspecific complaints such as weakness, headaches, or dizziness.

In summary, polycythemia is a broader term that encompasses an increase in red cell count, hemoglobin, and PCV, while polycythemia vera is a specific form of polycythemia caused by genetic mutations. Polycythemia vera is characterized by an increased red blood cell mass, leading to hyperviscosity and an increased risk of thrombosis.