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MAY 08, 2020 -- FRANCE — An unusually high number of children have been admitted to intensive care in France since April 15 with an inflammatory syndrome very similar to Kawasaki disease.
What do we know about this rare disease? How does the clinical picture of the children currently hospitalized differ from the classic symptomatology? How should they be managed?
Medscape French Edition asked Léa Cacoub, MD, a cardiologist at Lariboisière Hospital, Paris, to take stock.
What is the normal prevalence of Kawasaki syndrome? Are these new cases surprising?
This disease, which is the leading cause of childhood acquired heart disease in industrialized nations, is very rare. It affects around one child in 6000 in France and the United States, and one in 12,000 in the UK. It is more common in Japan, with an incidence of 1 in 1000.
The incidence is 2.5 times higher in patients of Asian origin than in those of Caucasian origin, which suggests a genetic predisposition. It is also surprising that there was no increase in cases of Kawasaki disease since the start of the Asian epidemic in December; at least, this was not reported in the Chinese or Japanese series.
There is an annual seasonal gradient, with winter and spring surges of the disease. But it has become clear over the past 3 weeks that an unusual number of children of all ages have been hospitalized with multisystem inflammation frequently associated with circulatory failure, with elements suggestive of myocarditis.
We are concerned about the epidemic nature of these cases of Kawasaki-like disease in our intensive care units in Île-de-France [the region around Paris], with at least 25 in 3 weeks and 9 in Necker hospital over the past 2 days (as of April 30).
On the other hand, contact with our British, Spanish, Italian, and Belgian colleagues confirms this as an emerging problem.
What is the link between Kawasaki disease and COVID-19?
The pathology of Kawasaki disease is still unknown, and several theories have been proposed, including the possibility of an infection by a microorganism that secretes toxins, and of a process linked to superantigens.
The involvement of the immune system is therefore very strongly suspected, probably mediated by a bacterial or viral agent, and as such the involvement of members of the coronavirus family has already long been suggested (as well as adenoviruses, the herpes virus, Epstein-Barr virus, and others).
Have you been asked to carry out special monitoring in your cardiology departments?
Within the medical community, memos are currently being disseminated in order to look out for the occurrence of this clinical picture in children, as it is predominantly a pediatric pathology. But in can also occur in adults, and cardiac damage linked to COVID-19 has already been widely described in Asian and, more recently, European cohorts.
Professor Damien Bonnet, MD, from Necker Hospital in Paris, sent us a note to be vigilant over the clinical presentation of our patients admitted to cardiology with COVID-19, and called for communication between doctors of suspicious cases, so as to collate national data and make progress over the association between COVID-19 and vascular diseases, including Kawasaki.
Does the syndrome currently seen in intensive care differ from the classical picture of Kawasaki disease?
The clinical forms are fairly similar to 'classic' Kawasaki disease. But the clinical presentation of recently treated pediatric cases is pleomorphic and may be an incomplete form of Kawasaki disease, especially as some patients have coronary dilatation.
The 20 or so cases identified in the cardiology and intensive care services at Necker Hospital have certain characteristics:
• In the few cases described, the manifestations suggestive of Kawasaki disease are seen between the second and fourth day of fever.
• They initially have a respiratory, hemodynamic, septic, or digestive presentation.
• They have an initial phase that can evoke a cytokine storm, possibly with signs of macrophage activation.
• Collapse is common, while systolic dysfunction of the left ventricle is variable but sometimes profound.
• Moderate troponin elevation.
• Faint changes on ECG.
• Documented coinfection with COVID-19.
Is the treatment the same?
It is. The treatment should be as early as possible. It is based on the the prescription of acetylsalicylic acid (aspirin), at 50 to 80 mg/kg/d during the acute phase, then 3 to 5 mg/kg/d, and on the administration of intravenous immunoglobulins, at 2 g/kg in a single dose.
The response to treatment is usually very good, with apyrexia achieved within a few hours. It has been shown that the prevalence of coronary artery abnormalities depends on the dose of immunoglobulins and not the dose of aspirin, as intravenous immunoglobulin therapy reduces the frequency of coronary aneurysms to less than 5%.
The administration of immunoglobulins should be early, ideally during the first week of the disease; however, if there are persistent signs of inflammation, treatment can continue even after the first week.
In the event of failure after immunoglobulin infusion, defined as the persistence or recurrence of fever 36 hours after the end of the infusion, a second or even a third therapeutic cycle can be performed.
Corticosteroids have long been contraindicated in Kawasaki disease, but recent data shows that corticosteroid therapy can now be recommended in the event of initial failure with immunoglobulins.
Acetylsalicylic acid is given at an anti-inflammatory dose during the acute phase and an anti-platelet dose in the subacute phase. In the absence of cardiac complications, a low dose is maintained until normalization of the sedimentation rate and platelet count.
In children with coronary artery anomalies, treatment is continued until complete regression of the coronary aneurysms, or for life if the aneurysms persist. In the case of giant aneurysm, there is sometimes a need for anticoagulation with vitamin K or heparin and, in selected cases, surgical intervention (bypass surgery, transplantation).