MAHA + thrombocytopenia; schistocytes, ↑LDH, ↑indirect bili. TTP adds fever/renal/neuro (↓ADAMTS13); HUS = E. coli O157:H7
TTP → Plasma exchange (+ steroids ± caplacizumab/rituximab); start caplacizumab at diagnosis with first PLEX (hold peri-procedure for bleeding risk); add LMWH VTE prophylaxis once platelets >50×10⁹/L (ISTH 2025)
HUS → supportive ± dialysis
Order set
- FBC, film (schistocytes)
- LDH, bilirubin, haptoglobin
- U&E, ADAMTS13
- Coags (usually normal)
Criteria
AdmitAll
ICUNeuro involvement, cardiac, rapid deterioration
DialysisAKI with AEIOU (esp. HUS)
DischargePlatelets/LDH recovering, off plasma exchange (TTP), renal stable
Never
- Transfuse platelets (fuels thrombosis)
- Give antibiotics in HUS (toxin release worsens it)
Clinical detail — differentials, red flags, pitfalls, disposition
Red flags
- Neuro signs
- AKI
- Rapidly falling platelets
Differentials
- DIC
- Malignant hypertension
- Pre-eclampsia/HELLP
Common mistakes
- Platelet transfusion
- Delaying plasma exchange in TTP
- Antibiotics in EHEC-HUS
Disposition & follow-up
Congenital TTP in remission → prophylactic recombinant ADAMTS-13 preferred over FFP (ISTH 2025 strong rec). TTP → urgent plasma exchange + haematology; HUS → supportive ± dialysis.
Discharge package
MedicationsAs per haematology (immunosuppression in TTP)
Follow-upHaematology; monitor counts/renal
Warning symptomsBruising, neuro symptoms, reduced urine
💊 Treatment detail — doses & preparation
Plasma exchangedefinitive (TTP)
DoseDaily PLEX (1–1.5 plasma volumes) until platelets >150 ×2 d
PreparationCentrifugal line, FFP replacement
MonitorADAMTS13 level, platelets daily
Prednisone (ITP/AIHA)corticosteroid
Dose1 mg/kg OD until platelets/Hb recover, then slow taper over weeks
PreparationTablets with food
MonitorGlucose, BP, mood; bone + gastric protection if prolonged
Rituximabanti-CD20
Dose375 mg/m² IV weekly ×4 (ITP/AIHA/cold agglutinin)
PreparationDilute in NS to 1–4 mg/mL; slow ramped infusion with premedication (paracetamol/antihistamine/steroid)
MonitorInfusion reactions (first dose), hepatitis B reactivation — screen first
Platelets contraindicatedsafety
DoseDo NOT transfuse platelets in TTP (microthrombi) unless life-threatening bleed
Preparation—
MonitorCaplacizumab add-on per haematology
📖 BSH TTP & HUSReviewed July 2026