Multisystem Inflammatory Syndrome In Children (MIS-C)

Updated 5/30/2023

MIS-C stands for multisystem inflammatory syndrome in children, a rare and serious inflammatory syndrome that affects children and young adults. It is associated with SARS-CoV-2, the virus that causes COVID-19 and usually occurs 2-6 weeks after infection with SARS-CoV-2.

It causes fever and inflammation and can affect different body parts, such as the heart, skin, eyes, and gastrointestinal organs. It can be very serious and children usually need to be treated in the hospital. However, almost all children get better with medical care.

MIS-C is very rare, and we do not know yet exactly what causes it. One possibility is that MIS-C is caused by an abnormal immune response to the SARS-CoV-2 virus, but we do not know yet why some children develop MIS-C after SARS-CoV-2 infection and some do not.

Signs and Symptoms

Because MIS-C can affect different body systems, there are many different symptoms that may occur.

The most commonly reported symptoms are:

• Fever
• Abdominal pain
• Vomiting
• Diarrhea
• Rash
• Bloodshot eyes

Patients with MIS-C have persistent fever, sometimes for 3 or 4 days. They may have dizziness or lightheadedness, which can be signs of low blood pressure. They may have excessive fatigue.

MIS-C shares some of the same features of Kawasaki’s disease, which usually affects children under 5 years of age and causes rashes, red eyes, and inflammation of the coronary arteries, along with swelling of the hands, feet and lymph nodes. It is not known whether these two conditions are related. Some findings in MIS-C are similar to a type of toxic shock syndrome seen with staph or strep bacteria.

Testing

There is no specific test to diagnosis MIS-C. The diagnosis is made using a combination of signs and symptoms along with blood tests. Some children need imaging tests such as echocardiograms (an ultrasound of the heart) to look for signs of inflammation. Many children with MIS-C test positive for SARS-CoV-2, the virus that causes COVID-19, with an antibody test and/or using a nasal swab, but not all.

Treatment

Children usually need supportive care in the hospital for their symptoms, such as intravenous fluids or medicines that increase blood pressure. Doctors may use various medicines to reduce inflammation, which generally includes steroids, intravenous immunoglobulin (IVIG), or both.

Some children will need to be treated in the pediatric intensive care unit (PICU). However, most children with MIS-C recover quickly with treatment. Children generally follow-up with a specialist and have repeat blood tests or echocardiograms to monitor them after leaving the hospital. Most children have a full recovery.

Prevention

The best way to prevent MIS-C is vaccination for COVID-19, including staying up-to-date with vaccine recommendations. Studies have shown that children who are vaccinated are much less likely to develop MIS-C. COVID-19 vaccination has also been associated with less severe illness with MIS-C, such as needing ICU-level care. COVID-19 vaccines can be given to a child with a history of MIS-C to protect them from getting COVID-19 again as long as they have fully recovered and it has been at least 90 days since their MIS-C diagnosis. Parents should talk to their healthcare provider about COVID-19 vaccination in these situations. Further information is available at CDC: Clinical Considerations for Use of COVID-19 Vaccines: COVID-19 and MIS-C.

Information for Parents

What to do if you think your child has MIS-C

• If your child is showing any of the symptoms of MIS-C, especially if they have been diagnosed with COVID-19 recently or been in contact with someone who has had COVID-19 recently, call your health care provider right away.
• If your child is having trouble breathing, pain or pressure in their chest, new confusion, bluish lips or face, severe abdominal pain, or you cannot wake them up, seek emergency care right away.

Information for Health Care Providers

The Council of State and Territorial Epidemiologists (CSTE) and CDC have developed a standardized surveillance case definition for multisystem inflammatory syndrome in children (MIS-C) associated with SARS-CoV-2 infection, effective January 1, 2023. This is not intended for use as a clinical case definition but is intended to be easier for public health surveillance staff to implement and reduce misclassification of cases. More information may be found at CDC: Information for Healthcare Providers about Multisystem Inflammatory Syndrome in Children (MIS-C).

Notify MDH

• Health care providers can report MIS-C cases to MDH at health.misc.casereport@state.mn.us.

Resources

• AskMayoExpert: COVID-19: Multisystem inflammatory syndrome in children (MIS-C)
  MIS-C triage, diagnosis, and clinical care flowchart algorithm from Mayo Clinic.
• American College of Rheumatology Clinical Guidance for Multisystem Inflammatory Syndrome in Children Associated with SARS-CoV-2 and Hyperinflammation in Pediatric COVID-19: Version 2. Henderson et al, Arthritis Rheumatol, April 2021.
• CDC: Clinical Considerations for Use of COVID-19 Vaccines: COVID-19 Vaccination and MIS-C and MIS-A
• CDC: MIS-C: Information for Healthcare Providers about Talking with Families and Caregivers
  Includes handouts on how to recognize MIS-C and what happens after a diagnosis of MIS-C in English and Spanish.

More about MIS-C

• CDC: Multisystem Inflammatory Syndrome