Multisystem inflammatory syndrome — a rare and severe COVID-19 complication first characterized in children — presents differently among adults and may be underdiagnosed as a result, according to a study published May 19 in JAMA Network Open.
Researchers at Vanderbilt University Medical Center in Nashville, Tenn., analyzed data on 15 hospitalized COVID-19 patients who met the working definition for multisystem inflammatory syndrome in adults, or MIS-A, between March 1 and Sept. 30, 2020.
Nine of 15 patients with MIS-A had acute COVID-19 symptoms. In most pediatric cases, children develop the complication after having a mild or asymptomatic COVID-19 infection.
"In adults, the overlapping symptoms of acute COVID-19 and MIS-A make differentiating the [two] diagnoses difficult," Eric Chow, MD, an infectious disease fellow in the department of medicine at the University of Washington in Seattle, said in an accompanying commentary also published in JAMA Network Open.
Researchers found only three of the 15 patients were diagnosed with MIS-A, even though they all met the criteria for the condition. Three patients were previously hospitalized for COVID-19 before being admitted for their MIS-A symptoms, and the median period between hospitalizations was 23 days.
The median number of organs affected by the illness was four, with the gastrointestinal, hematologic and kidney systems being the most commonly affected.
"These data suggest that, although uncommon, MIS-A has a more heterogeneous clinical presentation than previously appreciated and is commonly underdiagnosed," researchers said.
Editor's note: This article was updated May 21 at 3:30 p.m. CT. A previous version of this article included an incorrect title for Dr. Eric Chow. Becker's regrests this error.