A PerPLEXing Case of Refractory Thrombotic Thrombocytopenic Purpura

Introduction: Thrombotic thrombocytopenic purpura (TTP) typically presents with thrombocytopenia, microangiopathic hemolytic anemia, and renal dysfunction. Fever, fatigue and other neurological symptoms can be associated with it. Plasmapheresis (PLEX), often combined with corticosteroids, is the gold standard treatment for TTP. Recent trials have shown that caplacizumab improves platelet levels and reduces mortality, exacerbations, hospital stays and PLEX procedures. We present a unique case of refractory TTP complicated by FFP-induced anaphylaxis managed successfully with caplacizumab and PLEX. Case Description: A 35-year-old female presented with petechiae, dark urine, and bruising for 3 days. Initial workup revealed platelets of 9000, Hgb 11.2 g/dL, creatinine 1.6 mg/dL (baseline 0.6 mg/dL), hematuria on urinalysis, and positive hemolysis labs, indicative of TTP. Treatment included steroids and daily PLEX with FFP. However, during the fifth PLEX session, she developed anaphylaxis, requiring intubation. PLEX was resumed the next day due to worsening thrombocytopenia and creatinine levels. She underwent 19 PLEX sessions, escalated to twice daily for five days. Caplacizumab was administered from day 9 for 17 days. Additionally, she received one dose of bortezomib while awaiting caplacizumab. Her clinical course was complicated by multiple thromboembolic events, necessitating anticoagulation therapy. Due to bleeding risks, caplacizumab was discontinued. She was discharged home with a low dose of steroid taper with normal platelet count and renal functions. Discussion: TTP is a life-threatening hematologic disorder with high mortality if untreated. Standard treatment involves PLEX with FFP due to bleeding risk. Body weight influences the FFP volumes used in PLEX. High volume and multiple treatments increase FFP-related anaphylaxis risk, as seen in our case. Despite anaphylaxis, PLEX with FFP was resumed. Caplacizumab, later administered, significantly improved platelet count and reduced PLEX sessions, decreasing FFP usage. Despite challenges, favorable outcomes with caplacizumab mirror trial results, affirming its efficacy. Early caplacizumab initiation may expedite platelet count recovery and decrease PLEX sessions, mitigating FFP-related risks.