Exchange Before the Result Returns - Hematology clinical simulation case. A 34-year-old woman presenting with acute confusion, scattered petechiae on the...
A 34-year-old woman presenting with acute confusion, scattered petechiae on the trunk and lower extremities, scleral icterus, and profound fatigue after a week of flulike symptoms. Initial labs reveal a hemoglobin crash of 4 g/dL overnight with platelets at 14 x 10^9/L and schistocytes on peripheral smear.
Acute Resuscitation Milestones & Priorities
Clinical phases and key interventions encountered in this emergency module:
Initial Triage & Pentad Recognition
Renal Injury & MAHA Differentiation
Caplacizumab & Neurologic Decline
ICU Monitoring, Bleeding Restraint & Disposition
High-Yield Clinical Pearls
TTP is a clinical emergency. Mortality without plasma exchange exceeds 90%; with TPE, survival exceeds 80–90%. ADAMTS13 testing must never delay therapy.
The classic pentad (MAHA, thrombocytopenia, neurologic dysfunction, renal injury, fever) is present in fewer than 10% of cases; the triad of unexplained MAHA + thrombocytopenia + normal coagulation is sufficient to treat.
Plasma exchange is performed with FFP or cryoprecipitate-poor plasma as replacement; a central venous catheter is required for the high-flow circuit.
High-dose corticosteroids (IV methylprednisolone 1 g daily or prednisone 1 mg/kg/day) accompany TPE to suppress ADAMTS13 autoantibodies; rituximab accelerates autoantibody clearance and reduces relapse.
Caplacizumab, a bivalent nanobody against the A1 domain of von Willebrand factor, blocks platelet–vWF interaction and rapidly halts microthrombosis; it is administered upfront in high-risk presentations or at first clinical deterioration.
Platelet transfusion is contraindicated except for life-threatening bleeding (e.g., intracranial hemorrhage, airway bleeding). In ischemic events, transfusion fuels further microvascular occlusion.
Stroke-mimics in TTP are microvascular and respond to intensified TPE plus caplacizumab; thrombolytics are contraindicated in severe thrombocytopenia.
Hematology, transfusion medicine, and the apheresis team must be consulted within the first hour; ICU admission is standard until platelet count and LDH normalize sustainably.
Pregnancy, HIV, drugs (ticlopidine, cyclosporine), and post-hematopoietic stem cell transplant are recognized secondary causes; the work-up must include these triggers even in classic immune presentations.
Test Your Clinical Reasoning in Real Time
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