Multisystem inflammatory syndrome is an uncommon but serious condition where various body parts become inflamed. It is a post-infectious syndrome, representing a delayed and heightened immune system reaction that occurs after the body has fought off an infection. Even if the initial infection was mild, the subsequent inflammatory response can be significant, requiring hospital care. The condition was first identified in 2020, and understanding of it continues to evolve.
Symptoms and Bodily Impact
The signs of multisystem inflammatory syndrome can vary but often develop rapidly, beginning with a persistent fever lasting more than 24 hours. Many people also experience significant gastrointestinal issues, such as abdominal pain, vomiting, or diarrhea. A skin rash is another common indicator, along with red eyes (conjunctivitis).
Other observable signs include swelling in the hands and feet, swollen lymph nodes in the neck, red cracked lips, or a “strawberry tongue.” A profound sense of fatigue is a near-universal symptom, often accompanied by headaches or confusion. The condition affects numerous organ systems. The heart is frequently involved, with inflammation of the heart muscle (myocarditis) being a significant concern. The lungs can also be affected, leading to respiratory problems, as can the kidneys and brain.
Causation and Associated Triggers
The development of multisystem inflammatory syndrome is linked to a preceding viral infection, with SARS-CoV-2 being the most identified trigger. The condition is not caused by the virus directly, but by the body’s own immune response weeks after the initial infection has resolved. Researchers theorize that the immune system, after being primed by the virus, launches a widespread inflammatory attack on the body’s own tissues. This suggests some individuals may have a genetic predisposition to this type of immune overreaction.
This condition is categorized by age. In children and adolescents under 21, it is referred to as Multisystem Inflammatory Syndrome in Children (MIS-C). A similar condition observed in adults is called Multisystem Inflammatory Syndrome in Adults (MIS-A). While both stem from a similar post-infectious process, there can be differences in how they present.
The Diagnostic Journey
There is no single, definitive test to identify multisystem inflammatory syndrome. Physicians arrive at a diagnosis by evaluating symptoms, conducting various tests, and ruling out other conditions that can present similarly, like toxic shock syndrome or Kawasaki disease. The diagnostic process begins with a clinical assessment, looking for a prolonged fever and evidence of inflammation affecting multiple organ systems. A patient’s recent health history is also important, specifically a recent infection with SARS-CoV-2, confirmed through a diagnostic or antibody test.
To support a diagnosis, doctors rely on laboratory and imaging tests. Blood tests are used to detect high levels of inflammatory markers, such as C-reactive protein, and to assess the function of various organs, like the kidneys and liver. An echocardiogram, an ultrasound of the heart, is frequently performed to check for inflammation of the heart muscle and to assess overall heart function. Other imaging, such as chest X-rays or CT scans, may be used to examine the lungs and other affected areas.
Medical Interventions and Hospital Care
Treatment for multisystem inflammatory syndrome requires hospitalization, with many patients needing care in an intensive care unit (ICU). The primary objectives are to reduce the systemic inflammation and to provide support for any affected organs.
The main treatments administered to control the overactive immune response include intravenous immunoglobulin (IVIG) and corticosteroids. IVIG is a blood product containing antibodies that can help modulate the immune system, while corticosteroids are powerful anti-inflammatory medications. Supportive care is also a large part of managing the condition. This can include providing supplemental oxygen for patients with respiratory difficulties, administering intravenous fluids, and using medications to support blood pressure.
Recovery and Follow-Up
While the majority of individuals recover fully with medical treatment, ongoing follow-up care is important. After being discharged from the hospital, patients need continued monitoring to ensure there are no lasting effects from the widespread inflammation, particularly for organs that were significantly affected.
The heart is an area of special focus during recovery, as it is commonly involved. Regular appointments with a cardiologist are often recommended and may include repeat echocardiograms to monitor heart function and ensure that any inflammation has resolved completely. This post-hospital care ensures that potential long-term complications are identified and managed promptly.