P129 | Diagnostic pathway for thrombotic thrombocytopenic purpura: Case study

Premises: TTP is characterized by MAHA with thrombocytopenia and organ ischemia. The diagnosis is confirmed by a severe deficiency in ADAMTS 13 activity, either congenital or immune-mediated.Case study: A 51-year-old woman with a medical history of allergic diathesis, previous thyroidectomy for multinodular goiter, recent preterm pregnancy via IVF, gestational diabetes, and Still's disease treated with MTX, arrived at the emergency department with worsening dyspnea, anemia, and thrombocytopenia. UEC and uPLT transfusions were performed. He underwent an upper endoscopy which revealed Grade A esophagitis according to the Los Angeles classification. After 24 hours, the patient experienced an epileptic seizure. He underwent a cranial CT angiogram which documented a subtle, centimeter-sized nodular hyperdensity in the left temporal region with perilesional edema. Blood tests showed a white blood cell count of 12,400, hemoglobin of 7.7 g/dL, platelets of 7,000 µL, schistocytes at 5%, LDH of 1837 U/L, indirect bilirubin of 3.38 mg/dL, haptoglobin <10, and creatinine of 1.1 mg/dL, resulting in a PLASMIC score of 7. Therefore, TTP was suspected, and plasmapheresis (PEX) was initiated, pending the ADAMTS 13 assay results. After 12 hours, ADAMTS 13 activity was reported at 0.10% with inhibitors at 3.06 UB/mL. The patient was subsequently transferred to the reference hematology department to add caplacizumab to PEX. The patient thus achieved complete remission.Conclusions: TTP often requires a presumptive diagnosis due to its prognostic and management implications. ADAMTS 13 levels often have prolonged response times. The PLASMIC Score has been shown to be a useful predictor of ADAMTS 13 activity.