Covid-19 and children: What is Kawasaki disease that has been linked to the coronavirus?
Covid-19 in children has been linked to this disease for its similar symptoms. But what is Kawasaki disease? It is a rare inflammatory disease that occurs mainly in children under the age of 5 and can cause heart damage or even death.
Kawasaki disease, or Kawasaki syndrome, is vasculitis, an inflammatory condition that affects the walls of blood vessels, especially those of the coronary arteries. This disease was first identified in 1967 by Japanese pediatrician Tomisaku Kawasaki. Very rare in adolescents and adults, it is the leading cause of heart disease in children in industrialized countries. If left untreated, it can cause coronary aneurysms and lead to serious heart damage and even death.
What are the causes of Kawasaki disease?
New cases are reported throughout the year worldwide, most commonly in the spring or winter. However, the origin of this childhood disease is still unknown. The strongest hypothesis is that of an infectious agent that produces hypersensitivity or an abnormal response of the immune system, causing inflammation and damage to blood vessels. Another, more controversial hypothesis, indicates that Kawasaki disease could be related to an infection by microorganisms that secrete toxins called "superantigenic".
The researchers seem unanimous on one point: genetics plays an important role in triggering the disease, which is much more common in Asian populations. It is not hereditary or infectious (it will not pass from one child to another).
What are the symptoms of Kawasaki disease?
Children affected by Kawasaki disease have a poor general condition. Symptoms progress in stages. First, patients trigger a high fever (over 39 ° C) that lasts for at least 5 days and does not respond to treatment with antipyretics or antibiotics. It can be associated with irritability, headache, occasional lethargy, abdominal pain, or diarrhea. Then the following symptoms appear:
a rash that causes redness and peeling mainly on the trunk and extremities, often accentuated in the perineal region;
abnormal swelling of the neck glands (cervical lymphadenopathy);
eye irritation and redness (conjunctivitis);
inflammation of the throat, mouth and tongue (raspberry tongue), accompanied by red, dry and / or chapped lips;
damage to the feet and hands (swelling of the fingers and toes, followed by peeling and / or redness on the palms of the hands and soles of the feet)
In most cases, Kawasaki disease is considered atypical or incomplete, as patients do not have all the clinical signs of the disease or have unusual symptoms.
How is Kawasaki disease diagnosed?
The diagnosis of Kawasaki disease is based on clinical observation. It is difficult to ask because the symptoms can be confused with those of many childhood diseases (scarlet fever, measles, etc.) but also with reactions to medications.
What are the risks of complications from Kawasaki disease?
Cardiac complications occur in 25-30% of untreated patients. Cardiovascular disorders involving the pericardium, myocardium, endocardium, and coronary arteries may manifest early in the disease by disturbances of the heart rhythm (tachycardia, for example).
The most important complication is the risk of coronary artery aneurysm (CAA), which generally occurs 10 to 30 days after the onset of the disease. Most children will experience acute symptoms, without cardiac complications. In the absence of these coronary complications, the course of Kawasaki disease is usually favorable. Relapses are possible, but rare.
Almost 85% of children with Kawasaki disease are under 5 years old and the peak incidence is between 18 and 24 months. Cases of patients younger than 3 months or older than 5 years are rarer, but are associated with an increased risk of coronary artery aneurysm.
How to treat Kawasaki disease?
In the presence of suggestive symptoms, it is essential to consult a doctor or pediatric emergency. In the case of a confirmed or even suspected diagnosis, the child should be hospitalized for a possible heart attack. Cardiac ultrasounds should be performed regularly to monitor the development of a possible aneurysm.
Treatment for the condition involves infusing intravenous immunoglobulins and aspirin to prevent inflammation of the wall of the coronary artery. If initial treatment fails, corticosteroids can be administered to patients with high risk factors. If given early enoughOr, it can significantly reduce the risk of heart damage.
What is the link between Kawasaki disease and the new coronavirus?
In recent weeks, cases of Kawasaki disease have been reported in several European countries, including France. Several pediatric services have alerted Public Health France to the increase in young patients with inflammatory symptoms identical to those of Kawasaki syndrome. Similar cases have been observed in the United Kingdom, Italy and Spain.
Since March 1, 2020, 152 children have been hospitalized as a result of an inflammatory syndrome close to Kawasaki disease. On Tuesday, May 19, during a press conference, the Director General of Health clarified that for 98 of them, there was a possible link with Covid-19 disease. On Friday May 15 we learned of the death of a 9-year-old boy in the hospital in Timone (Marseille), after an inflammatory disease that reached his heart. According to Public Health France, he presented "a neurodevelopmental comorbidity". Investigations are ongoing.