The authors described the characteristics of hospitalized children who developed pediatric inflammatory multisystem syndrome temporally associated with COVID-19 (PIMS-TS).
The study design was a case series of 58 children from 8 hospitals in England admitted between March 23 and May 16, 2020. Each patient had persistent fever and laboratory evidence of inflammation meeting published definitions for PIMS-TS from the United Kingdom, the United States and the World Health Organization. The authors review clinical and laboratory characteristics from medical records, which were compared with clinical characteristics of patients with Kawasaki disease (KD; n=1132), KD shock syndrome (n=45) and toxic shock syndrome (n=37) using U.K. and U.S. hospital records from 2002 to 2019.
Of 58 children who met the criteria for PIMS-TS, 45 (78%) had evidence of current or prior COVID-19 infection. All children presented with fever and nonspecific symptoms, including conjunctival injection (45%), rash (52%), vomiting (45%), abdominal pain (53%) and diarrhea (52%). Twenty-nine developed shock and required inotropic support and fluid resuscitation, including 79% of the subgroup receiving mechanical ventilation.
Thirteen patients met the American Heart Association's definition of KD, and 23 had fever and inflammation without features of shock or KD. Eight patients (14%) developed coronary artery dilatation or aneurysm. Children with PIMS-TS tended to be older than those with KD or KD shock syndrome (median age 9 years vs. 2.7 years and 3.8 years, respectively) and had higher white blood cell count, neutrophil count, fibrinogen levels, troponin levels and C-reactive protein, as well as more profound lymphopenia and anemia and lower platelet counts.
There are several limitations of the study, including its retrospective data collection from several hospitals. Patient management was individualized by center and PCR testing of stool was not routinely undertaken of all participants. It is possible that viral replication is occurring in the gastrointestinal tract, endothelium or myocardial tissue, but because these samples were not available, this mechanism cannot be explored. Seroprevalence data among children within the United Kingdom are not available, so it is not possible to determine the background rate of COVID-19 IgG positivity in the population.
These findings help characterize the clinical features of seriously ill children with pediatric inflammatory multisystem syndrome temporally associated with COVID-19 and provide insights into this apparently novel syndrome. There is a wide spectrum of presenting signs and symptoms and disease severity, ranging from fever, inflammation and conjunctivitis to myocardial injury, shock and development of coronary artery aneurysms. The comparison with patients with KD and KD shock syndrome provides insights into this syndrome, and suggests this disorder differs from other pediatric inflammatory entities.
Diagnostic criteria for classic Kawasaki disease can be found in the following references: