COVID-19 positivity, myocarditis distinguish MIS-C from Kawasaki disease
COVID-19 positivity, older age at onset, and the presence of myocarditis are more common with multisystemic inflammatory syndrome in children than with Kawasaki disease, according to data published Pediatric Rheumatology.
“There is now mounting evidence on the existence of a childhood multi-inflammatory syndrome related to SARS-CoV-2 infection sharing some similarities with Kawasaki disease (KD) and Toxic Shock Syndrome (TSS),” Marco Cattalini, MD, of the University of Brescia, in Italy, and colleagues wrote. “This condition has been named such as Pediatric Inflammatory Multisystem Syndrome-temporally associated to SARS-CoV-2 infection (PIMS-TS) or Multisystem Inflammatory Syndrome associated with Coronavirus Disease 2019 (MIS-C).”
“However, the real extent of the clinical spectrum of disease, and the exact role of SARS-CoV-2 infection, are still poorly understood,” they added. “Moreover, it is still not clear if SARS-CoV-2 might also be considered a trigger for KD development or if KD, during the SARS-CoV-2 epidemic, presented peculiar and unusual clinical manifestations.”
To analyze the clinical features and treatment response of MIS-C, examine its relationship with Kawasaki disease and determine whether they are indeed distinct entities, Cattalini and colleagues conducted an observational, retrospective, multicenter study. The Rheumatology Study Group of the Italian Pediatric Society launched a national online survey on April 24, 2020, targeting patients diagnosed with Kawasaki disease or Kawasaki disease-like multisystemic disease during the COVID-19 pandemic. The researchers enrolled a total of 149 children hospitalized between Feb. 1, 2020, and May 31, 2020.
Participants included 96 children with Kawasaki disease and 53 identified as having Kawasaki disease-like multisystemic disease, or “Kawacovid.” The researchers collected demographic, clinical, laboratory data, treatment information and outcomes in an online, anonymized database. The relationship between clinical presentation and COVID-19 infection was also reported.
Cattalini and colleagues then compared the clinical characteristics of patients diagnosed with Kawasaki Disease during the COVID-19 pandemic to 598 children with the disease seen at three Italian pediatric hospitals from Jan. 1, 2000, to Dec. 31, 2019. The researchers used the Chi square or exact Fisher and non-parametric Wilcoxon Mann-Whitney tests to study differences between the two groups.
According to the researchers, children with Kawasaki disease-like multisystemic disease were significantly older at onset and presented more frequently with gastrointestinal and respiratory involvement. Cardiac involvement was also more common in patients with Kawasaki disease-like multisystemic disease, with 60.4% demonstrating myocarditis. Among those with Kawasaki disease-like multisystemic disease, 37.8% presented with hypotension or non-cardiogenic shock. The risk of ICU admission was also higher in patients with Kawasaki disease-like multisystemic disease.
Meanwhile, coronary artery abnormalities were more common in children with Kawasaki disease.
Other distinguishing characteristics of Kawasaki disease-like multisystemic disease included lymphopenia, higher C-reactive protein levels, and elevated ferritin and troponin-T, the researchers wrote.
Children with Kawasaki disease more frequently received immunoglobulins (IVIG) — 81.3% versus 66% (P=.04) — and acetylsalicylic acid — 71.9% vs. 43.4% (P=.001) — compared with patients with Kawasaki disease-like multisystemic disease. The latter group, meanwhile, more often received glucocorticoids — 56.6%, compared with 14.6% (P<.0001).
COVID-19 positivity was prevalent in 75.5% of children in the Kawasaki disease-like multisystemic disease group, compared with 20% among those with Kawasaki disease (P<.0001).
Comparing pandemic-era Kawasaki disease with historic Kawasaki disease, the researchers found no statistical difference in terms of clinical manifestations and laboratory data.
“Our study suggests that SARS-CoV-2 infection is the causative agent of PIMS-TS in children,” Cattalini and colleagues wrote. “Older age at onset and clinical peculiarities like the occurrence of myocarditis characterize this multi-inflammatory syndrome, which share specific clinical manifestations with KD. Our patients had an excellent response to treatment and a good outcome, with few complications and no deaths.”