- Multisystem inflammatory syndrome is a new disease that affects children with Covid-19
- Fever, vomiting and diarrhoea are some of the common symptoms – separate from the coronavirus
- Almost half of sufferers have abnormal heart ultrasounds
While children get off quite lightly from Covid-19, with a low mortality rate, doctors and researchers have noticed that the virus might have sparked a rare new disease.
A hyperinflammatory condition linked to the coronavirus has been identified and is being studied by researchers. It is called multisystem inflammatory syndrome in children (MIS-C). The disease is quite dangerous and could even be lethal.
"The definition of [MIS-C] across the organisations is based on six principle elements: paediatric age, persistence of fever, presence of laboratory markers of inflammation, manifestation of signs or symptoms of organ dysfunction, lacking an alternative diagnosis, and a temporal relation to Covid-19 infection or exposure," write the authors of a review of studies dealing with the mysterious disease.
Different from Kawasaki's and toxic shock
The new disease was first reported in April among UK patients, and other countries have since then also observed MIS-C in young Covid-19 patients. It's quite difficult to differentiate it from Kawasaki's Disease (KD) and toxic shock syndrome (TSS) due to similar symptoms, but it remains a separate disease.
"While MIS-C has overlapping features with KD and TSS, the inflammatory storm observed in MIS-C is much more intense.
"Another important difference to highlight between KD and MIS-C is that approximately 5% of children with Kawasaki's disease presented with cardiovascular collapse. Conversely, 60.2% of children with MIS-C presented with shock."
What to look out for
The researchers collated 39 observational studies involving 662 patients to better understand this new disease, publishing their findings in EClinicalMedicine. The cases – mostly from the US – had an average age of about nine and stayed around eight days in hospital.
Those with KD are normally younger, under the age of five.
About 71% of them were admitted to ICU, while only 1.7% died. This is higher than the child mortality rate for Covid-19.
The most popular symptoms were fever, which was present in all cases, while 73.7% suffered from abdominal pain or diarrhoea, and 68.3% from vomiting. Conjunctivitis and a rash were also frequently observed.
Abnormal heart scans
Less than a fifth was placed on a ventilator, but the biggest finding came from their echocardiographs, an ultrasound of the heart.
Just more than half of the scans were abnormal, most of them showing a depressed ejection fraction. This means that the percentage of blood being pumped out of a filled heart ventricle is below 50%.
"Although children were critically ill and had extraordinary inflammation, most responded to prompt administration of anti-inflammatory agents, namely intravenous immunoglobulin and corticosteroids.
"Among the more concerning findings was that children could still develop MIS-C despite an asymptomatic course of coronavirus 2019 disease. The literature reports that MIS-C typically manifests three to four weeks after SARS-CoV-2 infection."
Other worries are that just more than half of the patients had no other underlying health conditions – although half were obese – and the disease is disproportionately affecting African-descendant communities.
While the study offers valuable insight into the disease for clinicians, they caution that the studies have a low level of evidence and are mainly descriptive as the disease is still rare.
"Accordingly, children undergoing evaluation for MIS-C should have a baseline echocardiogram, electrocardiogram, and repeat imaging to follow cardiac function and artery change."
The long-term effects of Covid-19 – and MIS-C – are still unknown, and only time will tell what impact it could have on the health of younger generations.
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