Acquired Thrombotic Thrombocytopenic Purpura in the Presence of a Urinary Tract Infection: A Rare Pediatric Case

Thrombotic thrombocytopenic purpura (TTP) is a type of microangiopathic hemolytic anemia that rarely presents in the pediatric population. This life-threatening disorder manifests as severe consumptive thrombocytopenia and disseminated micro-thromboemboli, leading to organ ischemia. Here, we present a case of an acute first-time episode of acquired TTP in a 17-year-old African American female with a past medical history of obesity, recurrent urinary tract infections, and dysfunctional uterine bleeding managed with oral contraceptives. The disorder's insidious onset was only preceded by a urinary tract infection managed as an outpatient with oral cefdinir for four days before symptoms worsened. The patient was admitted to the pediatric intensive care unit with microangiopathic hemolytic anemia, severe thrombocytopenia, low von Willebrand factor-cleaving protease ( ) activity, hypofibrinogenemia, gross hematuria, and acute kidney injury. Further workup was significant for a positive urine culture for . Her hospital course was complicated by an acute ischemic stroke. The patient's TTP was managed by five sessions of plasmapheresis (PLEX), two once-weekly doses of rituximab, five doses of caplacizumab, three doses of high-dose solumedrol, and six days of high-dose prednisone. This regimen led to an overall uptrend in platelet counts toward normal and resolved her kidney injury. Currently, the patient continues to recover as an outpatient with no disability, managed with rituximab and caplacizumab as relapse prophylaxis. This case highlights the need for further investigation into the consideration of TTP as part of the differential diagnosis for pediatric patients presenting with severe thrombocytopenia and acute kidney injury in the absence of a significant medical history. Additionally, the utilization of rituximab, caplacizumab, steroids, and PLEX for TTP in the pediatric population should be further investigated.