Covid-related renal thrombotic microangiopathy: Role of plasma exchange

Introduction: The most common COVID-19 associated glomerular diseases are COVID associated nephropathy (COVAN) and Thrombotic Microangiopathy (TMA). Other less common glomerular diseases associated with COVID reported are antineutrophil cytoplasmic antibody (ANCA) vasculitis, anti-glomerular basement membrane (Anti GBM) antibody disease, podocytopathies, and IgA nephropathy. We report a case of TMA due to COVID-19 infection. Case Description: A 67-year-old woman with asthma was admitted for COVID related respiratory failure and was noted to have acute kidney injury with anemia and thrombocytopenia. She was hypertensive and urine analysis was notable for hematuria and proteinuria. ANA, ANCA, Anti GBM, Coombs, ADAMTS13, disseminated intravascular coagulation panel, serum immune fixation and free light chains, cryoglobulins, and infectious work up were unrevealing. Complement C3 and C4 were low, lactate dehydrogenase and bilirubin were high, haptoglobin was undetectable, and schistocytes were seen on peripheral smear which raised concern for thrombotic microangiopathy. Renal function deteriorated rapidly with ensuing anuria prompting initiation of dialysis. Kidney biopsy confirmed acute thrombotic microangiopathy. She was started on plasma exchange (PLEX) for COVID related thrombotic microangiopathy and she started producing urine with rapid improvement in creatinine (Cr) after two treatments. Cr was down to 3.11mg/dL from a peak of 7.45 mg/dL after PLEX and normalized at discharge. The patient is currently being monitored with renal panel and complete blood picture every three months, as an outpatient. Discussion: COVID is known to cause TMA that is presumed to be secondary to endothelial dysfunction and complement activation. There are no standard guidelines for treatment. Terminal complement blockade was not used in our patient. Our case demonstrates the efficacy of PLEX in the treatment of COVID related TMA. Early recognition and treatment is crucial and may reduce morbidity and mortality.