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)