Refractory thrombotic thrombocytopenic purpura temporally associated with COVID-19 infection requiring intensified plasma exchange: a case report

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening thrombotic microangiopathy caused by severe ADAMTS13 deficiency. Immune TTP (iTTP) has been reported in temporal association with coronavirus disease 2019 (COVID-19), although causality has not been established. We report a 23-year-old previously healthy woman who developed acute severe iTTP during confirmed COVID-19 infection, with severe ADAMTS13 deficiency and detectable anti-ADAMTS13 antibodies. Despite corticosteroids and daily therapeutic plasma exchange (TPE), thrombocytopenia and hemolysis worsened during the first admission. Rituximab and pulse corticosteroids were added. Caplacizumab was ordered from an external source; while procurement was pending and the patient was deteriorating, TPE was temporarily intensified to twice daily. She was discharged with a platelet count of 138 × 10 9 /L, below the formal clinical-response threshold, and returned two days later with recurrent thrombocytopenia, consistent with persistent/refractory disease rather than a true relapse. A further course of TPE, corticosteroids, and completion of rituximab was followed by hematologic recovery and normalization of ADAMTS13 activity. The case illustrates an aggressive iTTP course temporally associated with COVID-19 and the management challenges created by delayed access to caplacizumab; because intensified TPE, rituximab, and corticosteroids were used concurrently, disease control cannot be attributed to twice-daily TPE alone.