• Typical, sporadic form of TTP: auto-antibodies against ADAMTS-13 neutralize this vWF multimer protease --> multimer accumulation --> abnormal platelet adhesion and activation --> systemic microvascular aggregation of platelets --> CNS and other organ ischemia
  • Drug related (endothelial damage NOT related to ADAMTS-13): cyclosporine, gemcitabine
  • Stroke in TTP = usually microangiopathic but can be medium- and large-vessel related
  
  

  Posted 05/29/16 12:24:46 PM by Matthew Cummings

• Microangiopathic hemolytic anemia (schistocytes + ↑LDH/indirect bili) AND thrombocytopenia without an alternative apparent cause? Strongly consider TTP
  • Quick way to look for hemolysis is UA – check for presence of hemoglobin without RBCs
  • Differential: Sepsis, Malignancy, Severe HTN, HELLP/pre-eclampsia, APLS, Scleroderma crisis
  
  

  Posted 05/29/16 12:25:44 PM by Matthew Cummings

• Low threshold for plasma exchange if unexplained MAHA + thrombocytopenia (even if diagnosis not definitive), continue until platelets >150,000
  • Placing a central line for PLEX in patients with TTP and marked thrombocytopenia: do not give platelets unless actively bleeding, give FFP, and ensure the most experienced clinicians are doing the procedure (note: can give platelets in ITP)
  • If CNS symptoms or decompensation before initiation of PLEX --> FFP (replace ADAMTS13)
  • Must send assay for ADAMTS-13 and inhibitor titer before giving FFP (usually used for prognosis rather than to guide therapy given prolonged turnaround time and need for immediate treatment)
  
  

  Posted 05/29/16 12:26:53 PM by Matthew Cummings

• Severe/refractory TTP? Consider adjunctive therapies: glucocorticoids, rituximab
  
  

  Posted 05/29/16 12:27:45 PM by Matthew Cummings

• For further reading...

  TTP: Review Article (NEJM) 
  Comparison of Plasma Exchange with Plasma Infusion in the Treatment of Thrombotic Thrombocytopenic Purpura
  
  
  
  

  Posted 05/29/16 12:30:29 PM by Matthew Cummings

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