The link between SARS-CoV-2 and potential stress to kidneys is unclear, but damage to the organs has been documented in adults with COVID-19 too.
More than 10 percent of children hospitalized with COVID-19 or multisystem inflammatory syndrome, an inflammatory condition commonly known as MIS-C that in rare cases has followed SARS-CoV-2 infection, experienced acute kidney injury, according to a study published March 3 in Kidney International. Kids with kidney damage remained in the hospital an average of eight days longer than did other children facing these conditions without the added kidney stress.
“Recognizing that kidney function contributes to outcomes post-COVID is important to think about, especially in the pediatric population. These kids are young and have a whole life ahead of them,” says Abby Basalely, a pediatric nephrologist at Cohen Children’s Medical Center in New Hyde Park, New York, and a coauthor of the study.
People with acute kidney injury can have trouble regulating body fluids or urinating normally. The injury often resolves itself but will sometimes progress into chronic kidney disease, says Isabel Roberti, the director of the Children’s Kidney Center at RWJ Barnabas Health in West Orange, New Jersey.
There has been much more analysis of how COVID-19 affects adults’ kidneys than of how these organs are affected in children, so Basalely and colleagues wanted to document the incidence of acute kidney injury in kids with COVID-19 or MIS-C along with other short-term health outcomes. MIS-C, which involves fevers, persistent inflammation, and dysfunction in two or more organs including the kidneys, can be a delayed effect of having COVID-19. The researchers performed a retrospective analysis of the records of 152 minors admitted to four hospitals in New York’s Northwell Health System between March and August 2020.
The team defined acute COVID-19 as a positive SARS-CoV-2 test within 24 hours of hospital admission. Of the 97 children with acute COVID-19, 8 of them (8.2 percent) also had kidney injury. Another 55 children who did not have acute COVID-19 were diagnosed with MIS-C at hospital admission. Ten of these 55 children (18.2 percent) also had kidney injury. In total, 11.8 percent of the pediatric patients experienced kidney damage.
Black children were almost three times as likely to develop acute kidney injury as others were. Two of the 152 children died, one of whom had acute kidney injury.
Whether COVID-19 or MIS-C is the cause of the kidney damage is unknown, but Basalely suspects it is a consequence of SARS-CoV-2 infection. “There have been reports of [the virus] directly infecting kidney tissue,” Basalely says, though she notes that these reports are provisional and generally have come from adults. Besides a direct infection of kidney tissue, Basalely says, the body’s immune response to SARS-CoV-2 sometimes goes into overdrive and could lead to kidney inflammation.
The authors couldn’t rule out that some children identified with acute kidney injury may have experienced impaired kidney function before arriving at the hospital. Researchers did not have access to information about the kidney function of the children prior to entering the hospital, so their determinations of injuries were based on lab work conducted at admission or during the hospital stay. Half of the children with acute COVID-19 and kidney injury already had both conditions upon admission, as was true for 80 percent of those with MIS-C and kidney injury.
Other institutions do see evidence of kidney injury as soon as kids arrive at the hospital. “It aligns more or less with what we are seeing here in terms of acute kidney injury episodes, particularly with MIS-C,” says Siddharth Shah, the chief of pediatric nephrology at Norton Children’s Hospital in Louisville, Kentucky, who was not involved in the study.
Lara Danziger-Isakov, a specialist in pediatric infectious disease at Cincinnati Children’s Hospital in Ohio, has also treated episodes of acute kidney injury in children with COVID-19 or MIS-C. In her experience, this damage is less likely to be evident at hospital admission than it was in Basalely’s study.
Shah says he is concerned, like Basalely and Roberti are, that experiencing a bout of acute kidney injury could lead to worse problems down the line. Norton Children’s has established clinics to monitor long-term symptoms of children who have had COVID-19 or MIS-C, including signs such as elevated blood pressure or a loss of protein in urine that could indicate increased risk of chronic kidney disease, Shah says.