Pediatric multi-system inflammatory syndrome, or multi-system inflammatory syndrome in children (MIS-C), is a serious illness thought to be related to COVID-19, usually seen in children 3 to 6 weeks after an infection. The cause is not yet fully understood. It has been proposed that COVID-19 viral particles might enter the bloodstream from the digestive system.
Early in the COVID-19 epidemic, children with the virus were thought to develop Kawasaki disease, which affects the coronary arteries. These are the arteries that carry oxygenated blood to the heart muscle. Children with MIS-C can have any of the following signs and symptoms of Kawasaki disease:
- High fever
- Rash
- Redness or swelling of the hands, with peeling skin on the fingers and toes
- Red eyes without drainage
- Red, swollen tongue described as resembling strawberry
- Bumps (enlarged lymph nodes) in neck
- Irritability
- Joint pain due to temporary arthritis
- Diarrhea
- Vomiting
- Abdominal pain
MIS-C has also been compared with toxic shock syndrome, having the following signs and symptoms:
- High fever
- Disseminated rash
- Fast heart beat
- Light-headedness from low blood pressure (shock)
In addition, the following may be present:
- Abdominal pain and swelling
- Nausea and vomiting
- Diarrhea
- Confusion
Typical COVID-19 cough and shortness of breath can be present, but are not necessary for the diagnosis. Frequently children either test positive for COVID-19 or have been exposed during the previous four weeks, but this, too, is not always seen.
When MIS-C is suspected, blood and urine tests are performed for blood clotting, kidney function, and inflammation. An echocardiogram shows how well the heart is functioning. Chest X-rays show the condition of the lungs and size of the heart. Abdominal ultrasounds or CT scans may be performed as indicated by signs and symptoms. These tests are repeated throughout the course of the illness to measure the patient’s progress.
Patients are treated in hospitals by general pediatricians and specialists in the fields of pediatric cardiology, kidney disease, pulmonology, infectious disease, and rheumatology (arthritis).
Patients may be treated with a variety of medications as the need arises:
- IV immunoglobulins for Kawasaki-like illness
- antiinflammatory agents such as corticosteroids (dexamethasone, methylprednisolone, etc)
- medications to increase blood pressure (vasopressors)
- aspirin or heparin to prevent or reduce internal clot formation in the blood
Patients who have difficulty breathing may be given oxygen or treated in the intensive care unit with a breathing machine (ventilator). Fortunately, most children generally make a full recovery.