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)