Polycythemia

In polycythemia (thesaurus synonyms: Emotional polyglobulia; Acquired polyglobulia; Acquired polycythemia; Erythrocytosis; Forssell syndrome; High altitude polyglobulia; High altitude polyglobulia; Hypertensive polyglobulia; Hypoxemic polyglobulia; Nephrogenic polyglobulia; Plethora sanguinea; Plethora vera; Polycythaemia; Polycythaemia primaria; Polycythaemia rubra; Polycythaemia vera; Polyglobulia; Polyglobulia due to being at high altitude; Polyglobulia due to erythropoietin; Polyglobulia due to hemoconcentration; Polycythemia due to residence at high altitude; Polycythemia due to stress; Pseudopolyglobulia; Pseudopolycythemia; Relative polyglobulia; Renal polyglobulia; Secondary erythremia; Secondary polyglobulia; Secondary polycythemia; Stress polyglobulia; Symptomatic polyglobulia; Vaquez-Osler disease; Vaquez-Osler syndrome; ICD-10 D45: Polycythaemia vera; D75. 1: secondary polyglobulia) involves erythrocytosis (proliferation of erythrocytes, i.e., red blood cells in the blood). Polycythemias can be congenital or acquired. Several forms can be distinguished:

  • Primary polycythemia – polycythaemia vera (PV), benign familial polycythemia; erythropoietic stem cell disorder; autonomous proliferation of the three cell series.
  • Secondary polycythemia (polyglobulia) – isolated increased red cell count with normal plasma volume, eg:
    • Reactive stimulation of erythropoiesis (blood formation) in hypoxia (tissue oxygen deficiency; e.g., cardiac defects with right-to-left shunt, chronic lung disease, exposure to high altitude).
    • Renal (kidney-related) polyglobulia.
    • Hypertensive (high blood pressure-related) polyglobulia
  • Relative polycythemia (pseudopolyglobulia) – due to a decrease in plasma volume with isolated borderline or moderate increase in the number of erythrocytes (stress erythrocytosis).

Polycythaemia vera (PV) is one of the myeloproliferative neoplasms (MPN) (formerly chronic myeloproliferative disorders (CMPE)). These are diseases in which there is a proliferation of all three blood cell series (especially erythrocytes, but also platelets (thrombocytes) and leukocytes/white blood cells) in the blood. PV is the most common of the myeloproliferative neoplasms. The following other diseases are among the myeloproliferative neoplasms:

  • Chronic myeloid leukemia (CML).
  • Essential thrombocythemia (ET) – chronic myeloproliferative disorder (CMPE, CMPN) characterized by chronic elevation of platelets (thrombocytes)
  • Osteomyelofibrosis (OMF; synonym: osteomyelosclerosis, PMS) – myeloproliferative syndrome; represents a progressive disease of the bone marrow.

Two clinical stages of polycythaemia vera are distinguished:

  1. a chronic phase:
    • Increased red cell production and erythrocytosis (increase in the number of erythrocytes), which can last up to 20 years, and
  2. A progressive late phase (formerly called spent phase):
    • secondary medullary fibrosis with extramedullary hematopoiesis (blood formation outside the bone marrow) and increasing splenomegaly (enlargement of the spleen; up to 25% of patients) and/or by transition to:
      • Myelodysplasia (group of diseases of the bone marrow in which blood formation originates from genetically altered cells of origin (stem cells) rather than healthy ones) or acute myeloid leukemia (about 10% of patients)

Sex ratio: males to females is 2: 1 (with respect to polycythaemia vera). Frequency peak: the maximum incidence of polycythaemia vera is around the age of 60 years.The median age of patients at diagnosis is 60 to 65 years. The incidence (frequency of new cases) of polycythaemia vera is approximately 0.7-2.6 cases per 100,000 population per year. Course and prognosis: If the disease is not recognized, the survival time is only a few years. To date, polycythemia is not curable. However, adequate therapy can slow down the progression of the disease. Life expectancy is then not significantly limited.