This information was accurate at the time of publication. Due to the changing nature of the COVID-19 pandemic, some information may have changed since the original publication date.
Multisystem Inflammatory Syndrome in children (MIS-C) is a new type of health condition associated with COVID-19 that's being diagnosed among a small number of children across the world. MIS-C is a condition that causes different parts of the body to become inflamed, including the heart, lungs, kidneys, brain, skin, eyes, or gastrointestinal organs. It is unknown at this time what causes MIS-C, but children that have been diagnosed either had the virus that causes COVID-19 or had been around someone with COVID-19.
As health experts continue to learn about this new development, a panel of University of Utah Health and Primary Children's Hospital experts answered questions about what is known about MIS-C so far.
How was MIS-C discovered?
Andy Pavia, MD: Reports about MIS-C first came from the United Kingdom and London in April of 2020 of what appeared to be children who had Kawasaki Disease following infection of COVID-19. At the same time, similar cases were being reported in New York City and Italy. In both the UK and the U.S., the cases appeared to peak about a month after the peak of infection of COVID-19.
What are MIS-C symptoms?
- Fever
- Abdominal pain
- Vomiting
- Diarrhea
- Neck pain
- Rash
- Bloodshot eyes
- Feeling extra tired
Pavia: The illness is characterized with children who come in with prolonged fever. They often have severe abdominal pain and rash, then go on to develop inflammation of many organs, hence the name Multisystem Inflammatory Syndrome. The most common symptoms are rash and fever. Less common symptoms include red eyes, swelling of the hands and feet, or swollen lymph nodes.
What is the cardiovascular element to MIS-C?
Dongnan Truong, MD: This seems to be one of the most striking features. One of the most common heart findings we are seeing is that the muscle of the heart or squeeze of the heart is being affected. In some of these reports out of Europe and the UK, somewhere up to 50% of patients had decreased squeeze of the heart.
What conditions of MIS-C relate to Rheumatology?
Erin Treemarcki, MD: We take care of children with high levels of inflammation - specifically we see something that's called macrophage activation syndrome (MAS). MAS happens in a group of children who have a certain type of arthritis, though we did see it in other conditions as well. What happens is the immune system reacts to a trigger and either overreacts becoming very active or is unable to turn itself off and keeps producing levels of inflammation or in some degrees, both. We are seeing similar features in MAS and other types of significant inflammation in MIS-C patients.
How is MIS-C diagnosed?
A patient may undergo certain tests to look for inflammation or other symptoms. These tests might include:
- Nose swab
- Blood tests
- Chest x-ray
- Heart ultrasound
- Abdominal ultrasound
Pavia: A PCR test looks for the virus that indicates an active infection. In these children, it's present about a third of the time. The other two-thirds generally have antibodies but no virus, although some have both. The presence of antibodies indicates an infection in the past.
How is MIS-C being treated?
Pavia: Most children who become ill with MIS-C need treatment in the hospital. Some will need to be treated in the pediatric intensive care unit (ICU). The type of treatment currently being used for MIS-C patients is the treatment we use for Kawasaki Disease due to inflammation of the heart. Treatment has been effective. There have been a few deaths around the world so far and the majority of children have recovered well.
Truong: In terms of trial for MIS-C, we are still in the infancy of what we know. We don't know what works best at this point, but so far there has been promising evidence that IVIG has helped children with fever and inflammation.
MIS-C Cases
Pavia: One patient has been diagnosed with MIS-C in Utah. Earlier patients who presented with Kawasaki Disease will undergo testing to see if they actually had MIS-C. Worldwide, there are roughly 200 MIS-C cases.
Cases range to under one year up to 20 years of age. The average age is 7 to 8-years-old. This is different from Kawasaki Disease which usually affects preschool children, 2 to 3 years of age.
Of the Utah cases, how many have been severe?
Jill Sweney, MD: Of the handful of Utah patients, one required admission to the intensive care unit (ICU) and needed medication to support blood pressure. These patients usually turn around in 3-5 days, but some reported cases that we have been hearing about presented much sicker and required mechanical ventilation and ECMO support.
Pavia: Many of the patients that have been described so far have developed severe disease and have often ended up in the intensive care unit because of the heart muscle and the shock of low blood pressure.
What is the fatality rate?
Pavia: The threat is going to depend on how many children become infected with coronavirus. There's a lot we can do about that and can do to protect children such as social distancing, practicing good hand hygiene, and wearing masks. If we don't control the spread of infection, then eventually we will see more cases.
Why does MIS-C affect children and not adults?
Pavia: We don't know yet. There are a lot of things in the immune system in children that are quite different. The initial COVID-19 infection in children tends to be much milder - only 1-2% of cases in the US and around the world have been in children - and a very small percentage of children with the infection get sick enough to be hospitalized or receive intensive care. That's very different even from young adults.
What should parents know about MIS-C?
Pavia: MIS-C appears to be rare, but parents should be attuned to sickness in their children. If a child has prolonged fever, severe abdominal pain, a rash, and/or red eyes - contact your health care provider.
What we don't know about MIS-C
Pavia: MIS-C seems to follow at a substantial time after COVID-19 infection, but we don't know the spectrum of the disease. We also don't know what the long-term consequences, if any, are going to be.
What are doctors at U of U Health doing?
Pavia: We are trying to see if we can understand the immune system, how the virus triggers MIS-C weeks after the illness, what the best treatmenrs are, and if we can intervene early.
Andrew Pavia, MD, Chief of the Division of Pediatric Infectious Diseases
University of Utah Health and Primary Children's Hospital
Dongngan Truong, MD, Pediatric Cardiologist
University of Utah Health and Primary Children's Hospital
Jill Sweney, MD, Pediatric Critical Care Physician
University of Utah Health and Primary Children's Hospital
Erin Treemarcki, DO, Pediatric Rheumatologist
University of Utah Health and Primary Children's Hospital