Post-COVID-19 complement-mediated TMA: A case report.

Systemic COVID-19 disease is associated with a variety of organ involvement in infected patients. A rarely reported complication is the induction of complement-mediated thrombotic microangiopathy (TMA). TMA is an extremely rare pathological condition that results in thrombosis in capillaries and small arterioles, due to an endothelial injury. It is often combined with thrombocytopenia, Coombs-negative hemolytic anemia, and end-organ damage. This case involves a patient who was admitted to our hospital for the purpose of diagnosis and treatment of acute kidney injury (AKIN 3) with severe proteinuria after a preceding SARS-CoV-2 infection. A 77-year-old male patient had COVID-19 pneumonia in January 2021 with the need of high-flow oxygen therapy in the intensive care unit. In March 2021, he was hospitalized again due to elevated serum creatinine levels and proteinuria. The patient exhibited normal vital parameters. A renal biopsy showed severe TMA. A diagnosis of COVID-19-associated TMA was made, and treatment with high-dose glucocorticoid therapy and plasma exchange was initiated. Additionally, therapy with eculizumab was established. Unfortunately, the kidney failure was initially progressive, so that hemodialysis (HD) was temporarily necessary. In May 2021, kidney function recovered to an estimated glomerular filtration rate of ~ 30 mL/min/1.73m² corresponding to chronic kidney disease stage 3bA3 - 4A3. COVID-19-associated TMA is an extremely rare disease. TMA may be a possible long-term complication with the risk of end-stage renal disease if not properly diagnosed and treated.