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Multisystem Inflammatory Syndrome in Children (MIS-C)

Multisystem Inflammatory Syndrome in Children (MIS-C) is a rare but serious condition that sometimes develops in children who have or recently had COVID-19. Typically, COVID-19 affects the lungs and causes coughing and difficulty breathing. Unlike COVID-19, MIS-C can cause the heart and blood vessels to be weak.

At Children’s Health, we’ve cared for more than 100 children with MIS-C. Our experts from multiple medical specialties have streamlined our care so our teams can quickly recognize, diagnose and treat MIS-C. We also participate in national research to improve understanding of this new condition so that all children can get the right diagnosis and treatment.

What is Multisystem Inflammatory Syndrome in Children (MIS-C)?

MIS-C is thought to be related to the virus that causes COVID-19. In some children, the body’s immune system responds to a recent or current infection by developing high levels of inflammation. The inflammation can be an overreaction and can lead to organ damage. MIS-C can affect many organs including the heart, lungs, gut, kidneys, liver, skin, brain and eyes. When the body’s inflammation affects the heart and lungs, the organs in the body may not get the blood and oxygen they need to work well, which can be dangerous to your child’s health.

Most children diagnosed with MIS-C were previously healthy or had mild conditions like mild asthma or allergies. Many children did not show signs of COVID-19 at the time of infection, but later developed MIS-C. MIS-C can occur 2-6 weeks after infection.

What are the signs and symptoms of MIS-C?

MIS-C signs and symptoms can include:

  • Fever of 102° F or higher for longer than 24 hours
  • Abdominal pain
  • Diarrhea or vomiting
  • Dizziness or lightheadedness
  • Fatigue
  • Loss of appetite
  • Rash
  • Bloodshot eyes
  • Pale appearance
  • Fast or labored breathing

How is MIS-C diagnosed?

The CDC has created guidelines to help doctors diagnose MIS-C. Your child must meet all these criteria for a confirmed diagnosis of MIS-C:

  • Younger than age 21
  • Fever of at least 100.4° F for at least one day
  • Illness severe enough to need hospitalization
  • Signs of inflammation in blood test results
  • Signs of problems in multiple organs, including the kidneys, heart or liver
  • Evidence of recent or current COVID-19 infection, even if your child didn’t initially show symptoms of COVID-19
  • No other illnesses that could explain their signs and symptoms

Your doctor will perform tests to find out if your child meets these criteria. Tests may include:

  • Physical exam to look for a rash and general appearance
  • Blood tests to check for inflammation and see how well your child’s organs are working
  • Rapid antigen testing or PCR testing (from the nose or mouth) to check for current COVID-19 infection or antibody testing (from the blood) to check for prior COVID-19 infection
  • Chest X-ray to look for lung infections or lung damage
  • Echocardiogram to examine the structure of your child’s heart with an ultrasound
  • Electrocardiogram to check your child’s heart rate and rhythm

What causes MIS-C?

It’s not yet clear what causes MIS-C. However, evidence suggests that MIS-C occurs when a child’s immune system has an extreme response to the coronavirus SARS-CoV-2 (the virus that causes COVID-19). The immune system creates the inflammation that affects your child’s organs.

How is MIS-C treated?

There is no cure for MIS-C, but the experts at Children’s Health have developed a comprehensive approach to treating it. Multiple specialists collaborate to provide all the care your child needs. Your child will receive care that helps support the damaged organs. Usually, children need to be in the intensive care unit (ICU). Without this care, MIS-C can be life-threatening.

Most children with MIS-C need supportive care to help their damaged organs function while their body heals. This might include:

  • Extra fluids to support blood pressure
  • Medicines to raise low blood pressure and help the heart pump more strongly
  • Extra oxygen to ensure oxygen gets to all organs

Your child’s doctor might also use medicines that can calm an overactive immune system and reduce inflammation. These medicines have been used in other conditions with overactive immune system in children, like Kawasaki disease. They include:

  • Steroids
  • IV immunoglobulin
  • Anakinra (Kineret®)

Some children with MIS-C will need blood thinners because COVID-19 and related-illnesses like MIS-C can cause blood clots. Blood thinners help prevent blood clots, which can cause strokes or blockages in the lungs.

Most children with MIS-C spend 7-10 days in the hospital, including 3-4 days in the ICU, but some severe cases need more time to improve. Fortunately, most children bounce back quickly after treatment. However, they may need to limit physical activity until a heart doctor clears them.

Frequently Asked Questions

  • My child hasn’t had COVID. How did they get MIS-C?

    Most kids who get MIS-C show no symptoms or mild symptoms of COVID-19. They may not be tested for COVID-19 until they develop MIS-C, which can occur a few weeks after infection.

  • Does MIS-C cause long-term health effects in children?

    Since MIS-C is a new condition, we don’t yet know what the long-term effects of this condition are. It is encouraging that many children recover, but we do not know if the inflammation or organ damage increases risk for other conditions later in life.

  • Do all children who get COVID-19 get MIS-C?

    No. MIS-C is still rare but serious and can be life-threatening without care.

  • Is MIS-C contagious like COVID-19?

    No, MIS-C is not contagious. It is the result of an immune system reaction to the virus that causes COVID-19. However, if the virus is still in the body at the time of MIS-C diagnosis, then the virus is contagious.

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