Kawasaki and Covid-19 disease: symptoms, case in France

At the end of April 2020, doctors alerted the authorities to cases of pediatric multisystem inflammatory syndromes (PIMS) observed in young children with symptoms similar to Kawasaki disease and most of them with Covid-19 infection. 19 recent. In Italy, the United Kingdom, Belgium, but also in France, learned pediatric societies and health authorities have set up active surveillance of these atypical clinical pictures. Between March 1, 2020 and May 23, 2021, 563 cases of pediatric multi-system inflammatory syndromes (or PIMS) were reported, indicates Public Health France on May 27. What are the symptoms ? The sequelae and the treatments? Explanations.

Definition: what is Kawasaki disease?

Kawasaki disease or "lympho-cutaneous-mucosal syndrome" was described by Tomisaku Kawasaki in 1967. It is a vasculitis that is to say a disease characterized by an inflammation of the blood vessels which, in the absence of treatment, can be complicated by coronary aneurysms which can be fatal. Although this disease has been reported worldwide, it is much more common in Asian populations, especially in Japan. It affects in the vast majority of cases, infants and young children before puberty. This disease is rare in adolescents and adults.

How many cases in France and at what age?

The alert in France was given in April by the Necker hospital which reported the cases of 25 children hospitalized in intensive care in the Paris region with an inflammatory syndrome. "This inflammatory syndrome involves the heart, the lungs or the digestive system, explained doctor Damien Bonnet, coordinator of the M3C Necker network in Paris to the daily Midi Libre. The clinical condition of some patients is reminiscent of the Kawasaki disease."Some children had had a recent Covid-19 infection. In order to better identify these atypical clinical pictures, hospital pediatricians have been invited, since April 30, to report each new case possibly linked to Covid-19 to Public Health France, as well as retrospectively since March 1, 2020. .

► Between March 1, 2020 and May 23, 2021, 563 cases of pediatric multi-system inflammatory syndromes (or PIMS) were reported, reports Public Health France on May 27. The cumulative incidence of PIMS related to COVID-19 (491 cases) has been estimated at 33.8 cases per million inhabitants in the population under 18 (i.e. 14,511,544 inhabitants, Insee 2019 data).

What is the link with Covid-19?

The alert first came from the United Kingdom where the National Health Service (NHS, the country's health agency) reported in April the cases of a dozen children hospitalized in serious condition with fever, inflammation of the arteries (associated with "pediatric multi-system inflammatory syndromes" (PIMS) close to Kawasaki disease) and mostly positive for Covid-19. According to a study carried out at Robert-Debré Hospital (Paris), the incidence of cases similar to Kawasaki disease increased by 500% in April 2020 in the establishment, compared to the last 15 years.

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For Professor Albert Faye, head of the pediatrics department at Robert-Debré hospital interviewed by Francetvinfo, the link between Covid-19 and Kawasaki disease in children "appears quite clearly" since at this time , SARS-Cov-2 was “the only” respiratory virus circulating. “An average time to onset of PIMS cases of 4 to 5 weeks after infection with SARS-CoV-2 was observed during the first wave, reports Santé Publique France. “The data collected confirm the existence of a rare pluri-systemic inflammatory syndrome in children with frequent cardiac involvement, linked to the Covid-19 epidemic, also observed in other countries.

What are the symptoms?

Children with Kawasaki disease are in poor general condition. Symptoms suggestive of Kawasaki disease:

In Covid-positive children with PIMS: this is a "more marked" form of Kawasaki disease, with "digestive damage, abdominal pain", describes Professor Albert Faye . The inflammation is "a little more important than in the classic disease", with damage to the heart, inflammation of the heart muscle and inflammation in the pericardium, inflammations "more frequent than in Kawasaki disease" classic.

Risks: fatal consequences?

The seriousness of this disease is defined by the cardiac risks it can cause, in the absence of treatment. "Cardiac complications occur in 25 to 30% of untreated patients, reports La Revue du Praticien. The most important complication is represented by coronary aneurysms, which usually occur between 10 and 30 days after the onset of the disease." of the 196 patients for whom the link with Covid-19 was possible, probable or confirmed, PIMS was associated with myocarditis for 141 cases (72%), indicates Public Health France on November 19. Among the 58 patients with no established link, myocarditis was only found for 5 of them. A stay in intensive care was necessary for 118 children (46%) and in a critical care unit for 44 children (17%). Only one child, aged 9, died, in a picture of systemic inflammation with myocarditis

How is the diagnosis made?

The diagnosis of Kawasaki disease is difficult to make at first, because many childhood illnesses have similar symptoms. It is before the association of the aforementioned signs, typically five of the six signs mentioned above, that the diagnosis is confirmed. A blood test is sometimes carried out showing inflammation at its level, but in the event of confirmation of Kawasaki disease, a cardiac ultrasound must be performed in search of a coronary aneurysm, that is to say a malformation of a artery of the heart which makes all the seriousness of this infantile disease. Thrombosis, blood clots obliterating a blood vessel, can also complicate this disease.

What are the treatments?

Kawasaki disease requires hospitalization. Pathology is treated with the help of a drug combination. Aspirin is used to prevent the formation of thrombosis, associated with a course of immunoglobulins passed through the veins. "There may be a little more resistance to immunoglobulins, notes Professor Faye. But quickly, we manages to improve things, if necessary, by combining corticosteroids". In addition, cardiac ultrasound should be repeated to monitor the occurrence of a possible aneurysm. "Kawasaki disease has become exceptionally serious since it was treated early and effectively with immunoglobulins" explains Dr Fanny Bajolle of the "M3C-Congenital Congenital Heart Malformations" Reference Center at the Necker Enfants Malades Hospital. . Relapses are possible but rare.

Sources:

COVID-19: epidemiological update of November 19, 2020, Public Health France, November 19, 2020.

Kawasaki disease in four pictures. Dr. Fanny Bajolle. "Complex Congenital Cardiac Malformations-M3C" Reference Center at the Necker Enfants Malades hospital. 2011.

Kawasaki disease; R. Cimaz*, J.-C. Lega; Hospice Civils de Lyon, Claude-Bernard University, Lyon-1; 2007.