The reading WAidid recommends this week is a recent article published on Pediatric Infectious Disease Journal 2016 Nov 30, "Twelve Years of Kawasaki Disease in Portugal: Epidemiology in Hospitalized Children".

SUMMARY:
Kawasaki disease (KD) is an acute febrile illness with multisystemic vasculitis that predominantly occurs in children under 5 years of age with a male predominance.  It has now been reported worldwide in all ethnic and racial groups, but with significant different incidence rates. KD is the leading cause of acquired heart disease in developed countries.
The etiology of the disease remains unknown, despite 4 decades of research. The leading hypothesis is that KD reflects an abnormal inflammatory response to one or more infectious triggers and environment factors in genetically susceptible individuals.
The first case of KD in Portugal was reported in 1981. In 2001 the Portuguese Pediatric Society started a Pediatric surveillance unit for KD, whose adherence was considered suboptimal. For this reason, the authors started an extended study protocol for KD patients follow up, specially focused on long term cardiovascular sequelae, endothelial function and precursors of atherosclerosis evaluation. In this study the authors analyzed data from the national database of hospital discharge diagnostic codes regarding hospitalized children classified with KD code for a period of 12 years (2000 - 2011). Using these data, they estimated the number of the KD hospitalizations, the number of patients with the disease and the mean annual incidences of KD among children in Portugal.
A total of 533 hospitalizations were registered among 470 individuals aged less than 20 years in Portugal: 393 patients were grouped <5 years of age (85%) and 109 in the subgroup less than 1 year old (23%). The mean age at admission of all patients was 2.8 years and 61% of patients were male; 58,9% patients were hospitalized in the Lisbon region. The mean length of hospital stay was 9 days. The incidence peaked in the spring months (35%) and the vast majority during spring/winter (63% of cases) months. During the studied period there was an average of 39 new patients of KD per year, and four peaks of total hospitalized patients, years 2000, 2004, 2008 and 2011.
Cardiac involvement was reported in 12.9% of patients, predominately in male (P= 0.001). The most frequent cardiac lesion was the development of coronary artery aneurysms (CAA), followed by pericarditis, mitral valvulitis, and supraventricular tachycardia. The vast majority of cases with CAA occurred in children younger than 5 years of age and in the subgroup of children aged 1-4 years. There were two deaths (0.4%), attributed to myocardial infarction.
The general population incidence of KD was 1.9 per 100,000 individuals, with the highest incidence in children under 5 years old (6.48 per 100,000 children), followed by older children (1.1 per 100,000 children), and almost null for patients older than 9 years old.
The incidence of KD was significantly higher in boys, with the highest rate occurring in male infants under 1 year of age (11.4 per 100,000).
The incidence of KD was higher in the regions with a higher density of population.
Although the authors themselves highlighted some limitations, this was the first large scale epidemiological study of KD in Portugal, which provides a national estimate of hospitalizations associated with physician-diagnosed KD among Portuguese children.

AUTHORS: Fátima F. Pinto, Sérgio Laranjo, Miguel Mota Carmo, Maria João Brito, Rui Cruz Ferreira