What are causes of erythrocytosis?

Primary

• Congenital (erythropoietin receptor mutations)
• Polycythemia vera
• Idiopathic erythrocytosis

Secondary

• Congenital
  • Defects in oxygen sensing pathway – Chuvash erythrocytosis (VHL mutation)
  • Left shift of hemoglobin (Hb) oxygen dissociation curve:
    • High affinity Hb
    • 2,3-DPG deficiency
• Acquired
  • Hypoxia-driven:
    • Central process:
      • Chronic lung disease
      • Right-to-left cardiopulmonary shunts
      • Carbon monoxide poisoning
      • Smoking
      • Sleep apnea
      • High altitude
    • Local process:
      • Renal artery stenosis
      • Hydronephrosis
      • Renal cysts
  • Pathological erythropoietin production:
    • Tumors:
      • Hepatocellular carcinoma
      • Renal cell cancer
      • Cerebellar hemangioblastoma
      • Uterine leiomyoma
      • Pheochromocytoma
      • Meningioma
  • Drug-associated:
    • Erythropoietin
    • Androgens
    • Diuretics

Learn more here.