Paroxysmal nocturnal hemoglobinuria PNH

  • Facts:
    Acquired disorder of hematopoietic cells
    Complement mediated hemolysis
  • History / PE:
    Pancytopenia with hemolytic anemia
    Hematuria
    Fatigue, SOB
  • Diagnosis:
    Increased reticulocyte count and LDH
    Decreased haptoglobin levels (INTRAvascular hemolysis)
    Sugar water test
    Flow cytometry
    Negative COOMBs test
    Low leukocyte alkaline phosphatase (LAP)
  • Treatment:
    Supportive
  • Notes:
    PNH is the only hemolytic anemia caused by an acquired (rather than inherited) intrinsic defect in the cell membrane (deficiency of glycophosphatidylinositol leading to absence of protective proteins on the membrane)
  • Associated With:
    Recurrent thrombosis at unusual sites (eg. portal vein thrombosis or Budd-Chiari syndrome )
    Aplastic anemia
    MDS
  • Differential Diagnosis:
    1) Chronic myelogenous leukemia (also low LAP)
    2) Hereditary spherocytosis (AD inheritance/family history, extravascular hemolysis, normal serum haptoglobin)



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August 5th 2010