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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
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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
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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
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Severe/refractory TTP? Consider adjunctive therapies: glucocorticoids, rituximab
Posted 05/29/16 12:27:45 PM by Matthew Cummings
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For further reading...
Posted 05/29/16 12:30:29 PM by Matthew Cummings