Morgan’s parents weren’t too concerned in August of 2021, when her daughter had a fever. After all, she’d recovered from COVID-19 just a few weeks before. Her parents figured it was just a cold.
But within a few days, the 8-year-old was admitted to the hospital with a high fever, rash, aches, and stomach pain. Her heart rate skyrocketed while her blood pressure dropped. She stayed in the hospital for about two weeks, where doctors gave her corticosteroids to ease the inflammation rioting through her body.
Her COVID-19 infection weeks before had triggered an immune response that went haywire and damaged some of her organs. Even after leaving the hospital, doctors regularly tested Morgan for signs of heart damage.
Early in the pandemic, hospitals started seeing kids like Morgan, who had recovered from COVID-19 only to experience dangerous inflammation weeks later. The condition is called Multi-System Inflammatory Syndrome (MIS-C), and as of Jan, 3, 2023, it affected more than 9,333 children in the U.S., according to the Centers for Disease Control and Prevention (CDC), and less than one percent (0.8%) of those children died from the illness. It has become less common over the course of the pandemic but remains one of the most serious risks of COVID-19 for children.
Black children have had more severe outcomes from MIS-C than white children, according to a January 2023 study in JAMA. The same study showed that when only one or two organs were affected, 5% of children experienced adverse effects from medications, such as corticosteroids and immunoglobulin, the two main treatments for MIS-C, given in the hospital.
But when the inflammation attacked six or more organs, 18% of children experienced side effects of medications such as high blood sugar, muscle weakness, and changes in mood from steroids, as well as headaches, nausea, and vomiting from immunoglobulin.
Black children made up about a quarter of MIS-C hospitalization, but a third of the most severe cases (in which more than six organs had been affected.)
Like Morgan, many children with MIS-C need to be monitored for months after they leave the hospital and must return gradually to regular physical activities.
MedShadow reached out to pediatric cardiologist at KIDZ Medical Services, Carlo Zeidenweber, MD, to explain what MIS-C is, how it is typically treated, and along with what you need to know.
The following is a Q&A with the doctor. It has been lightly edited for brevity and clarity.
MedShadow: What is MIS-C?
Zeidenweber: SARS-CoV-2 (the virus that causes COVID-19) was a new virus that the human body wasn’t really aware existed. I think what ended up happening is that the virus came in, and the immune system didn’t really know how to respond. Some children’s immune systems over reacted, and that ended up causing inflammation in multiple organs.
This usually happened, not during COVID, but a couple of weeks after. Children would have COVID, sometimes mild, sometimes asymptomatic, and sometimes with more severe symptoms. And then we started seeing, two to six weeks after that, they would come to the hospital with very high fevers, rashes, or abdominal pain. And then we started noticing that the inflammatory markers were very elevated.
People should be aware that patients may get sick several weeks after [COVID-19]. Sometimes the MIS-C is more serious than the actual virus and it is the most common thing that we watch for in children.
MedShadow: Is MIS-C exclusive to COVID?
Zeidenweber: I’ve been practicing medicine for over 20 years. I did not see any cases of MIS-C prior to COVID. Whether we just didn’t recognize it, is a different story. MIS-C presents in a very similar way to a disease that we were frequently seeing specially as pediatric cardiologists called Kawasaki disease. It’s not exactly the same, but it’s similar.
MedShadow: What signs should parents look for in their children?
Zeidenweber: A lot of parents do not understand what MIS-C is, and that’s completely understandable. They should be aware that if their kid had COVID, regardless of how symptomatic they were, that several weeks after, there can be a bad rebound.
If they see their kid is sick, two to six weeks after COVID for any reason, MIS-C should definitely be in the back of their mind, especially if the child has fever, especially if they have a rash, and especially if they have severe abdominal pain.
MedShadow: Is the inflammation from MIS-C more likely to attack certain organs? Which symptoms are most common?
Zeidenweber: The most common symptoms would either be the fever, the skin rash, or abdominal pain. But the most concerning one is the heart. In the vast majority of the patients who get MIS-C, the heart was okay, but obviously, that’s the most concerning one, and that’s the one that you look for first.
MedShadow: What is MIS-C treatment like?
Zeidenweber: There were some cases of MIS-C in which we admitted the kids to the hospital, and we didn’t give any type of treatment. We just watched and made sure that they weren’t getting worse. If they were getting better, we didn’t treat them at all.
The vast majority that we ended up treating, we treated with IVIG which is immunoglobulin that decreases the cytokines. [Editor’s note IVIG is an antibody that’s given through your veins. Cytokines are a type of protein involved in your immune response.] We also use steroids. Sometimes we use a combination of IVIG and steroids.
And if the patient was very sick, then we had to do things to keep the patient alive, like give medications to support the heart, to increase the heart rate, increase the blood pressure, and so forth.
MedShadow: What is recovery like?
Zeidenweber: It’s like anything in medicine, you know, with anything in medicine, there is a big spectrum. I’m sure there were cases in which parents never took them to the hospital. There are cases that are mild, that resolve spontaneously. There are cases that are moderate that require medications. There are cases that are severe, for which we would give intensive treatment, and few cases in which patients really do die.
But, I would say that the vast majority of them are mild and they self-resolve. The problem is like you don’t know which kid is going to get really, really sick.
