COVID-19 and the Kidney: Should Nephrologists Care about COVID-19 rather than Maintaining Their Focus on Renal Patients?

Clinical Background: The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rapidly spread globally from late 2019, reaching pandemic proportions. Epidemiology: The related disease, COVID-19, exacerbates and progresses due to patients' abnormal inflammatory/immune responses, widespread endothelial damage, and complement-induced blood clotting with microangiopathy. COVID-19 manifests mainly as a respiratory illness. In cases of severe viral pneumonia, it may lead to acute respiratory distress syndrome, respiratory failure, and death. Challenges: Many extrapulmonary manifestations commonly occur, and a substantial proportion of patients with severe COVID-19 exhibit signs of kidney damage. Clinically, kidney involvement ranges from mild/moderate proteinuria and hematuria to acute kidney injury (AKI) requiring renal replacement therapy (RRT). The pathophysiologic mechanisms of kidney damage and AKI in patients with COVID-19 remain unclear but are known to be multifactorial. Current knowledge implies direct SARS-CoV-2-dependent effects on kidney cells (tubular epithelial cells and podocytes) and indirect mechanisms through the systemic effect of viral infection secondary to the critical pulmonary illness and its management. Prevention and Treatment: Standard-of-care strategies apply, as there is no specific evidence to suggest that COVID-19 AKI should be managed differently from other types in severely ill patients. If conservative management fails, RRT should be considered. The choice of RRT approaches and sequential extracorporeal therapies depends on local availability, resources, and expertise. The focus should now be on the long-term follow-up of COVID-19 patients, especially those who developed kidney injury and dysfunction. This represents an opportunity for integrated multidisciplinary research to clarify the natural history of COVID-19 renal sequelae and the best therapeutic interventions to mitigate them.