Thrombotic thrombocytopenic purpura TTP

• Facts:
  Platelet microthrombi block off small blood vessels
  
  Leads to end organ ischemia and dysfunction
  
  RBCs get fragmented by contact with microthrombi, leading to hemolysis
• History / PE:
  Classic HUS triad (thrombocytopenia, ARF, hemolytic anemia ) + fever and neurologic changes (delerium, stroke, seizure)
  
• Diagnosis:
  Largely clinical
  
  Schistocytes on blood smears
  
  Nucleated RBCs
  
  Normal coagulation factors
  
  Elevated indirect bilirubin, LDH, and AST
  
  Low haptoglobin
• Treatment:
  Corticosteroids
  
  Emergent plasmapheresis
  
  Splenectomy (rare)

  *Platelet transfusions (contraindicated)
  
  **TTP is fatal in 80% of cases

• Pneumonic:
  “FAT RN”

  F ever
  
  A nemia (hemolytic)
  
  T hrombocytopenia

  R enal failure
  
  N eurological abnormalities

• Notes:
  Type of microangiopathic hemolytic anemia (MAHA), along with HUS, DIC

  Though to be due to either a deficiency or autoantibody against a specific von Willebrand factor-cleaving protease (ADAMTS-13), which causes accumulation of large von WIllebrand factor multimers and platelet aggregation

• See Also:
  Clotting disorders
• Differential Diagnosis:
  HUS (classic triad)
  
  DIC (prolonged PT and aPTT time)
  
  HELLP (affects pregnant women)