Multisystem inflammatory syndrome in children: lessons learned, next steps

At the virtual 2021 American Academy of Pediatrics National Conference & Exhibition, Ibukun Kalu, MD, discussed what is known about the pathophysiology of multisystem inflammatory syndrome in children and implications for related diseases such as Kawasaki syndrome.

"Evidence is constantly changing and we expect new guidance and therapeutics in the coming months," began Ibukun Kalu, MD, assistant professor, and medical director of Pediatric Infection Prevention at Duke University in Durham, North Carolina on her presentation of MIS-C at the virtual 2021 American Academy of Pediatrics National Conference & Exhibition. Kalu first took a look at the history and current definition of this disease, noting that “paediatric inflammatory multisystem syndrome” associated with COVID-19 was first described in the United Kingdom in April 2020. The increase in cases of this Kawasaki Disease (KD)-like syndrome started about 2 weeks after the rise in acute COVID-19 infections, Kalu noted. Subsequent cases described in the United State became known as MIS-C.

“The first lesson here,” Kalu said, “is that, with surging community rates of COVID-19, we expect subsequent surges of MIS-C cases.” Current data, Kalu explained, shows very high peaks from this past summer up through September, due to the Delta variants spreading amongst other changes in behavior and protocol practices. The CDC tracking graph also shows MIS-C cases starting to peak this past summer, going from some 20,000 cases in the United States in early July to roughly 130,000 in late August.

Kalu next addressed racial disparities of MIS-C, with both Hispanic and non-Hispanic Black children having higher rates of both COVID-19 and MIS-C. “Data from the CDC summarizing patients with MIS-C by ethnicity and age group shows children aged 6 to 11 years old who are Hispanic and non-Hispanic Black having the highest number of cases,” said Kalu. A study of 869 hospitals from March 2020 to October 2020 showed 39% of children hospitalized were Hispanic, as opposed to 25% who were non-Hispanic White. Additionally, children requiring hospitalizations for COVID-19 were more likely to have cardiac or congenital heart disease, prematurity, immunocompromising conditions, obesity and other comorbidities.

Kalu went on to summarize the common symptoms of COVID-19 in children, which include cough and fever, fatigue, headache, abdominal pain, diarrhea, nausea, and poor appetite.

“Current variants of concern,” said Kalu, is Alpha, first identified in the United Kingdom, which spreads much faster than other variants. The Delta variant clearly seems to have more severity in adults, commented Kalu, “Although the concern is that we will start seeing more kids hospitalized from this and also have more post COVID-19 symptoms.”

Kalu then pointed to the similarities between MIS-C and KD. The mean age of children developing MIS-C is 8.5 years; with KD, 3 years. There are, however, many similarities in symptoms, including fever, rash, conjunctivitis, with some level of lymphadenopathy occurring in both. “However,” notes Kalu, “there does seem to be more cardiac dysfunction and gastrointestinal symptoms when MIS-C is the diagnosis.” And, death associated with MIS-C is still higher than death associated with KD. Kalu went on to review symptoms leading to diagnostic certainty of MIS-C, which include fever for more than 3 consecutive days and 2 or more of clinical features, including rash, gastrointestinal (GI) issues (abdominal pain, vomiting, diarrhea), shock/hypotension, and neurologic (altered mental status, headache, weakness, etc.)

Kalu moved on to her next point, that GI symptoms with signs of cardiac inflammation should raise in the practitioner the suspicion of MIS-C. Treatments for MIS-C include immunoglobulins plus or minus steroids, and aspirin due to the cardiac inflammation. Quite often anticoagulations may also be used.

The good news, Kalu noted, is that “currently, long-term morbidities or complications after MIS-C are rare. While long-haul COVID-19 symptoms include fatigue, headache, attention disorder, hair loss, and dyspnea, a new study in the Journal of the American Medical Association showed, that, at a 1 year follow up, 76 patients who had MIS-C showed normalized lab tests and no deaths.

For practitioners, Kalu recommended telling patients and caregivers “there are increased risks of MIS-C after a COVID-19 infection in some patients,” to use awareness of the disproportionate impact of COVID-19 and MIS-C to inform decisions, and to commit to reviewing updated guidance on recommended therapeutics for COVID-19 and MIS-C that can be used safely for children.

Reference

Kalu I. Multisystem Inflammatory Syndrome in children: lessons learned, next steps. American Academy of Pediatrics 2021 National Conference & Exhibition; virtual. Accessed October 10, 2021.