What parents need to know about multisystem inflammatory syndrome in children (MIS-C)

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As pediatric rheumatologists at Texas Children’s, we see children with a range of rheumatic diseases including juvenile idiopathic arthritis, systemic lupus erythematosus, dermatomyositis, auto inflammatory diseases, vasculitides (inflammation of blood vessels), and inflammatory brain disorders. A fairly new condition that we treat is a pediatric inflammatory illness linked to COVID-19.

In September, our multidisciplinary team of experts, including rheumatologists, cardiologists, critical care and hospitalist physicians at Texas Children’s, treated more than 30 patients with multisystem inflammatory syndrome in children (MIS-C), a condition in which various organs – most commonly gastrointestinal, heart, skin, eyes and less commonly kidneys and brain – become inflamed. Although the exact mechanism that causes MIS-C is still unknown, experts from the Centers for Disease Control and Prevention (CDC) and academic pediatric institutions, such as Texas Children’s, believe that MIS-C is related to an inappropriate activation of inflammation pathways 3 to 6 weeks after a mild COVID-19 illness or exposure to the SARS-CoV-2 virus in previously healthy children.

MIS-C has become more prevalent this fall due to the significant spread of the COVID-19 delta variant this summer, children returning back to school (and often unmasked), and lack of eligibility for the COVID vaccines in kids less than 12. The average age of kids impacted is 8 and 9 year olds; teenagers seem to have more severe cases but kids of any age may require ICU care for low blood pressure or heart dysfunction. MIS-C is a syndrome of the unvaccinated. Very few of our MIS-C cases have been fully vaccinated prior to exposure to the SARS-Cov-2 virus and development of MIS-C.

Understandably, COVID-19 and MIS-C have created much anxiety among parents. I’ve been asked this question many times: What precautions can I take to protect my children from MIS-C? First, I think it is important to make sure you follow all local and national expert recommendations regarding protecting our children from COVID. This includes wearing a mask at school and other large indoor settings, practicing social distancing when able and getting the COVID-19 vaccine if you’re eligible. Currently, children 12 years of age and older are eligible to receive the COVID-19 vaccine. We anticipate that the FDA and CDC may approve the vaccine for ages 5-11 within the next few days. We hope vaccinations in this age group will help in reducing rates of MIS-C. Secondly, parents should be aware of the symptoms of MIS-C, seek the guidance of their pediatricians if they are worried, and seek care immediately if signs and symptoms consistent with MIS-C have developed.

What causes MIS-C after a child is infected with the coronavirus?

Based on research in the past 15 months, MIS-C is thought to be caused by an overactive immune system in response to exposure or illness with COVID-19, leading to abnormal inflammation throughout the body. In a small percentage of kids (less than 1% of exposed children), as the immune system makes protective antibodies, it makes some errors and activates an inappropriate inflammatory response. Most children recover from MIS-C after being hospitalized and treated with a variety of anti-inflammatory interventions (usually a combination of intravenous corticosteroids, intravenous immunoglobulins and/or medications called biologics that are usually utilized for such disorders as juvenile arthritis). A majority of children develop low blood pressure (hypotension) and heart inflammation (myocarditis) and may require care in an intensive care unit (ICU). However, in rare cases, the illness can lead to death.

What are the early signs and symptoms of MIS-C that parents should be aware of?

Common symptoms of MIS-C include fever, GI symptoms (such as abdominal pain, vomiting or diarrhea), red eyes (conjunctivitis) or skin rash. Children often have a high fever that doesn’t respond to traditional anti-inflammatory measures such as Motrin or Tylenol. Sometimes, the child may complain of muscle pain, have poor drinking or eating and may be very tired. As a child becomes more ill, or has heart involvement, he or she may experience chest pain or have more difficulty breathing. Symptoms usually present three to six weeks after a mild COVID infection or exposure to COVID-19. We encourage parents to call their pediatrician right away if their child shows any of these symptoms and discuss the need to be evaluated.

According to the CDC, not all children with MIS-C exhibit the same symptoms. Therefore, it is important for doctors and parents to be vigilant of emergency warning signs and seek medical care immediately.

Are children with underlying illnesses more at risk of developing MIS-C?

We don’t believe this condition is more common in children with pre-existing conditions. Since the pandemic began, we’ve learned when a child gets the coronavirus infection, their body elicits an overactive immune response to this infection – and that is what results in MIS-C. With that said, this syndrome does not appear to be more common in children who have underlying health conditions. Yet, more severe primary COVID infections may be seen in children with underlying illnesses or immunocompromised status.

What makes Texas Children’s poised to care for patients with MIS-C?

We have a multidisciplinary team at Texas Children’s that includes cardiologists, rheumatologists, critical care, hematologists, hospitalists, emergency care physicians, and infectious disease physicians, among others, who are uniquely suited and skilled to care for these patients due to their vast expertise in treating Kawasaki disease (another post-infectious inflammatory condition affecting the heart) and now caring for the largest group of MIS-C patients in the United States.

The symptoms of MIS-C mirror many characteristics of Kawasaki disease including high fever, rash on the chest, back and abdomen, red eyes, inflammation of the mouth, lips and throat, enlarged lymph glands in the neck, and redness and swelling of the hands and feet. Unlike MIS-C, which typically affects older children and adults, Kawasaki disease tends to be clustered in much younger children and mostly affects the vessels of the heart and less frequently the heart muscle (as it does in MIS-C).

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