Nephrology and COVID-19

Initial reports about the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemic suggested that the incidence of kidney complications was low. Few would have anticipated the profound effect that the coronavirus disease 2019 (COVID-19) pandemic would have on the field of kidney health care. Early in the pandemic, it became apparent that patients with kidney disease were particularly vulnerable to SARS-CoV-2. In addition, it also became apparent that acute kidney injury (AKI) was occurring at several-fold higher rates in hospitalized patients with COVID-19 in the US than in earlier series in China.

The etiologies underpinning the high incidence of AKI need to be better understood. Several pathologic series suggest that acute tubular necrosis is the predominant form of kidney injury. However, proteinuria, hematuria, and leukocyturia appear to be common with COVID-19–associated AKI; megakarocytosis, thrombosis, and pigmented casts (possibly consistent with rhabdomyolysis) have been observed pathologically, and collapsing glomerulopathy has been reported. It is probable that the pathophysiology of COVID-19–associated AKI is more multifaceted than AKI observed with other causes of sepsis and critical illness. It is likely that this excess AKI may lead to chronic kidney disease in some patients; however, follow-up data on longer-term deteriorations in kidney health due to COVID-19 are currently lacking.