Synopsis
Recognise thrombotic microangiopathy before the classic pentad, send ADAMTS13 correctly, start plasma exchange, corticosteroid and caplacizumab urgently, and prevent relapse through immune surveillance.
- TTP is a thrombotic microangiopathy caused by severe ADAMTS13 deficiency, usually from an acquired autoantibody and rarely from biallelic inherited variants.
- Without ADAMTS13 cleavage, ultra-large von Willebrand factor multimers capture platelets in small vessels, causing organ ischaemia, thrombocytopenia and red-cell fragmentation.
- Most patients do not present with the historic pentad; thrombocytopenia and microangiopathic haemolytic anaemia without another clear cause should trigger immediate action.
Key red flags
Thrombocytopenia, fragments and haemolysis with normal routine coagulation requires immediate TTP service contact and treatment.
Investigation priorities
Confirm platelet consumption and red-cell fragmentation.
Management branches
Thrombocytopenia and microangiopathic haemolysis occur without a clear alternative cause.
- Call the regional TTP team, assess brain, heart, kidneys, abdomen and bleeding and calculate a validated probability score without delaying transfer.
- Send pre-plasma ADAMTS13, inhibitor and TMA samples according to the reference laboratory instructions while preserving treatment urgency.
Key medicines
CaplacizumabGive the licensed 10 mg intravenous dose before plasma exchange then 10 mg subcutaneously after each exchange and daily after exchange for the protocol-defined period, extended if immune activity persists.
RituximabThe TTP centre uses an intravenous induction regimen scheduled around plasma exchange, commonly 375 mg/m² weekly for four doses, with premedication and infection screening.