Thrombotic Thrombocytopenic Purpura: Management

Key points

• TTP is a thrombotic microangiopathy caused by severe deficiency of ADAMTS13 (the protease that cleaves von Willebrand factor), so ultra-large vWF multimers drive platelet-rich microthrombi. Usually acquired/immune (anti-ADAMTS13 antibodies); rarely congenital.
• Classic pentad — microangiopathic haemolytic anaemia (schistocytes), thrombocytopenia, neurological signs, renal impairment, fever — but the full pentad is uncommon; MAHA plus thrombocytopenia with no other cause should trigger urgent treatment. ADAMTS13 activity under 10% confirms.
• URGENT treatment, do not wait for ADAMTS13: plasma exchange (PLEX) is the cornerstone (start the same day); add corticosteroids and caplacizumab (anti-vWF nanobody); give rituximab for immune TTP.
• Do NOT transfuse platelets (may worsen microthrombosis) unless there is life-threatening haemorrhage. Give folate; add VTE prophylaxis once platelets recover.
• Distinguish from HUS (renal-predominant, often Shiga-toxin E. coli O157 in children; ADAMTS13 normal). Antibiotics do not treat TTP, and antibiotics in Shiga-toxin HUS may worsen it.