What is multi-system inflammatory syndrome in children?

Multi-system inflammatory syndrome in children (MIS-C), also known as pediatric multisystem inflammatory syndrome, is an extremely rare condition in which different parts of the body —including eyes, skin and some internal organs — become inflamed. MIS-C is a serious condition requiring hospital care.

Causes of multi-system inflammatory syndrome in children

Almost all children diagnosed with multi-system inflammatory syndrome have also tested positive for antibodies to SARS-CoV2, the virus that causes COVID-19.

Most children with COVID-19 experience mild symptoms and need no advanced medical care. For a very small number of children, however, COVID-19 seems to set off an excessive immune response resulting in inflammation throughout the body, or MIS-C. Symptoms of MIS-C typically appear 4 weeks after initial infection with COVID-19, but generally appear anytime between 3 to 6 weeks after infection.

Scientists and researchers across Children’s Hospital of Philadelphia (CHOP) are working hard to learn more about the potential causes of MIS-C. There is currently no evidence suggesting that people can contract MIS-C from others.

Symptoms of multi-system inflammatory syndrome in children

The symptoms of MIS-C generally appear between 3 to 6 weeks after initial infection with COVID-19, and may include:

• High fever that lasts for several days
• Diarrhea
• Abdominal pain (sometimes severe)
• Rash
• Changes in hands and feet
• Swollen lymph nodes
• Cracked lips
• Conjunctivitis
• Extreme fatigue and/or irritability

Some children with MIS-C also experience shock, which affects blood pressure and heart function. These children require critical care in the Intensive Care Unit (ICU).

Although many of the symptoms of MIS-C are similar to those of Kawasaki disease and toxic shock syndrome, MIS-C appears to be a distinct condition. However, medications used to treat Kawasaki disease have also been successfully used to treat MIS-C.

Testing and diagnosis of multi-system inflammatory syndrome in children

MIS-C is a newly discovered syndrome, and there is no one test to diagnosis a patient with the condition. For patients with symptoms of MIS-C, clinicians perform a thorough evaluation, which may include bloodwork and other tests. Patients are also tested for the presence of antibodies to SARS-CoV2, the virus that causes COVID-19.

Treatment for multi-system inflammatory syndrome in children

Children diagnosed with MIS-C are treated with medications often used to treat Kawasaki disease, including steroids and intravenous immunoglobin (IVIG). These medications reduce the body’s excessive immune response, lowering fever and inflammation and allowing heart function to return to normal.

Prognosis of multi-system inflammatory syndrome in children

Most patients diagnosed with MIS-C recover quickly with treatment. Because this is a newly discovered syndrome, however, the long-term outlook of this condition is still unknown. If your child has been treated for MIS-C, they may need follow-up clinical care. CHOP’s Division of Infectious Diseases cares for children with severe or unusual infectious diseases. To make an appointment, contact 267-425-3377.