New findings report that the incidence of Kawasaki disease (KD) is increasing in the United Kingdom and Ireland, and the rate of cardiac sequelae is higher in the United Kingdom and Irish patients than in other countries, despite most patients receiving intravenous immunoglobulin (IVIG) therapy.
The prospective British Paediatric Surveillance Unit survey received 601 reports of KD between 1 January 2013 and 28 February 2015, of which 38 were duplicates, 9 were other diagnoses and 1 had no clinical information. Of the remaining 553, there were 389 cases of complete KD; 46 atypical cases with fewer than 4 clinical features but with abnormal echocardiograms; and 116 cases of incomplete KD.
The age-specific annual incidence of KD in children under 5 years of age was 4.55/100,000 in the latest survey, which demonstrates a significant increase compared to the incidence of 3.4/100,000 that was reported in 1990. The latest data suggest the incidence of KD among 5-9 year olds stands at 1.26/100,000 and 0.08/100,000 in 10-14 year olds. Mortality from KD was 0.36%.
Although 94% of cases received IVIG, the rate of coronary artery aneurysms (CAAs) was 19%, and all-cardiac complications affected 28%. Those with CAA received IVIG later than in those without CAA (median 10 vs 7 days). Those under 1 year of age had the highest CAA rate (39%) and 5% of aged less than a year developed giant CAA.
Presenting the findings in Archives of Disease in Childhood, the authors say treatment delay is likely to have contributed to the high CAA rates. They advise that general practitioners and paediatricians should be aware that treatment to completely ablate systemic inflammation as early as possible is required to prevent lifelong cardiac sequelae, and that the historic KD therapeutic adage of ‘treatment within 10 days’ is no longer fit for purpose.