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Polycythemia

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Polycythemia

  1. 1.  Increase in Hb above normal.  Can be real or apparent due to decrease in plasma volume [ spurious or relative polycythemia or Gaisböck's syndrome ]
  2. 2.  Erythrocytosis: documentation of increased red cell mass  Polycythemia: any increase in red cells
  3. 3.  Abnormally high Hb >17g/dl in males and >15 g/dl in females  Haematocrit >50 percent in males and >45 percent in females.
  4. 4.  To differentiate from spurious or relative eruthrocytosis,  Measure red cell mass  If < 36ml/kg in men or < 32ml/kg in females, it is spurious or relative polycythemia.
  5. 5.  POLYCYTHEMIA can be  Primary : polycythemia vera associated with low erythropoetin levels  Secondary : associated with high erythropoetin levels
  6. 6.  A normal erythropoietin level, however, does not exclude a secondary cause for erythrocytosis or PV.
  7. 7.  Tissue hypoxia:  lung or heart disease  AV or intracardiac shunt  high altitude  CO poisoning  high affinity haemoglobinopathy
  8. 8.  Abnormal overproduction of erythropoetin  renal cysts  renal artery stenosis  tumors with ectopic EPO production
  9. 9.  Familial form of polycythemia  Rare  Associated with normal erythropoetin levels but hyperresponsive EPO receptors due to mutations.  VHL mutations ( chuvash polycythemia )
  10. 10.  Differentiate whether due to tissue hypoxia or autonomous EPO production  Measure arterial O2 saturation  If low saturation (< 92 percent) living at high altitude if not, evaluate for heart or lung disease
  11. 11.  Smokers : elevated EPO levels due to displacement of O2 by CO. Smoker’s polycythemia [ high HbCO levels]  Incresed O2 affinity haemoglobinopathy.
  12. 12.  EPO producing neoplasms: Hepatoma uterine leiomyoma renal cancer or cysts cerebellar haemangiomas adrenal tumors phaeochromocytoma meningioma
  13. 13.  Drugs causing polycythemia: Androgens recombinant erythropoietin
  14. 14.  h/o smoking  Living at high altitude  h/o congenital heart disese, sleep apnea, chronic lung disease
  15. 15.  Related to hyperviscosity and thrombosis  Digital ischaemia  Budd chiari syndrome with hepatic vein thrombosis  Abdominal vessel thromboses
  16. 16.  Neurological symptoms: vertigo tinnitus headache visual disturbances  Hypertension
  17. 17.  Aquagenic pruritus and symptoms related to hepatosplenomegaly in patients with polycythemia vera  Easy bruising  Epistaxis  Bleeding from GIT  Peptic ulcer disese
  18. 18.  Symptoms of hypoxemia cyanosis on exertion headache impaired mental acuity fatigue
  19. 19.  Ruddy complexion  Splenomegaly ( favours polycythemia vera )  Cyanosis or evidence of right to left shunt suggests congenital heart disease  Pulmonary artery hypertension d/t increased blood viscosity  Raised pulmonary vascular resistance d/t hypoxemia  Cor pulmonale
  20. 20.  PV is a clonal disorder involving a multipotent hematopoietic progenitor cell in which phenotypically normal red cells, granulocytes, and platelets accumulate in the absence of a recognizable physiologic stimulus.
  21. 21.  The etiology of PV is unknown.  Nonrandom chromosome abnormalities such as 20q and trisomy 8 and 9 have been documented in up to 30% of untreated PV patients
  22. 22.  mutation in the autoinhibitory, pseudokinase domain of the tyrosine kinase JAK2—that replaces valine with phenylalanine (V617F), causing constitutive activation of the kinase— appears to have a central role in the pathogenesis of PV.
  23. 23.  JAK2 gene is located on the short arm of chromosome 9, and loss of heterozygosity on chromosome 9p, due to mitotic recombination is the most common cytogenetic abnormality in PV.  loss of heterozygosity in this region leads to homozygosity for the mutant JAK2 V617F.  More than 90% of PV patients express this mutation
  24. 24.  splenomegaly may be the initial presenting sign in PV,  the incidental discovery of a high hemoglobin or hematocrit.  aquagenic pruritus,  no symptoms distinguish PV from other causes of erythrocytosis.
  25. 25.  Erythema, burning, and pain in the extremities, a symptom complex known as erythromelalgia, is another complication of the thrombocytosis of PV due to increased platelet stickiness
  26. 26.  Given the large turnover of hematopoietic cells, hyperuricemia with secondary gout, uric acid stones, and symptoms due to hypermetabolism can also complicate the disorder.
  27. 27.  When PV presents with erythrocytosis in combination with leukocytosis, thrombocytosis, or both, the diagnosis is apparent.  However, when patients present with an elevated hemoglobin or hematocrit alone, or with thrombocytosis alone, the diagnostic evaluation is more complex
  28. 28.  Assay for JAK2 V617F has superseded other tests for establishing the diagnosis of PV.
  29. 29.  Only three situations cause microcytic erythrocytosis: -thalassemia trait, hypoxic erythrocytosis, and PV.  With -thalassemia trait the RDW is normal,  whereas with hypoxic erythrocytosis and PV, the RDW is usually elevated due to iron deficiency
  30. 30.  Thrombosis due to erythrocytosis is the most significant complication, and maintenance of the hemoglobin level at 140 g/L (14 g/dL; hematocrit <45%) in men and 120 g/L (12 g/dL; hematocrit <42%) in women is mandatory to avoid thrombotic complications.  Phlebotomy serves initially to reduce hyperviscosity by bringing the red cell mass into the normal range.
  31. 31.  Periodic phlebotomies serve to maintain the red cell mass within the normal range and to induce a state of iron deficiency that prevents an accelerated reexpansion of the red cell mass.  In most PV patients, once an iron-deficient state is achieved, phlebotomy is usually only required at 3-month intervals.
  32. 32.  Anticoagulants are only indicated when a thrombosis has occurred  Asymptomatic hyperuricemia (<10 mg%) requires no therapy, allopurinol should be administered to avoid further elevation of the uric acid when chemotherapy is employed to reduce splenomegaly or leukocytosis or to treat pruritus
  33. 33.  Generalized pruritus intractable to antihistamines or antidepressants such as doxepin  interferon (IFN-)  psoralens with ultraviolet light in the A range (PUVA) therapy  hydroxyurea
  34. 34.  Asymptomatic thrombocytosis requires no therapy unless the platelet count is sufficiently high to cause an acquired form of von Willebrand's disease  Symptomatic splenomegaly can be treated with IFN-
  35. 35.  Pegylated IFN- produces complete remissions in PV patients.  Anagrelide, a phosphodiesterase inhibitor, can reduce the platelet count and, if tolerated, is preferable to hydroxyurea because it lacks marrow toxicity and is protective against venous thrombosis.
  36. 36.  Alkylating agents and radioactive sodium phosphate (32P) are leukemogenic in PV, and their use should be avoided.  hydroxyurea is the preferred cytotoxic agent, but it does not prevent either thrombosis or myelofibrosis in this disorder, is itself leukemogenic, and should only be used for a short time
  37. 37.  In some patients., massive splenomegaly unresponsive to reduction by therapy and associated with intractable weight loss will require splenectomy.  Allogeneic bone marrow transplantation may be curative in young patients.
  38. 38.  Most patients with PV can live long lives without functional impairment when their red cell mass is effectively managed with phlebotomy alone.  Chemotherapy is never indicated to control the red cell mass unless venous access is inadequate.
  39. 39. THANK YOU

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