Objective: To examine cognitive, academic and behavioural functioning following Kawasaki Syndrome(KS) with and without intravenous gammaglobulin (IVIG) treatment.

Design: Sibling matched, case-control study.

Subjects: Age 6-18 years meeting CDC KS criteria, >1 year after diagnosis, and pair-matched with sibling controls.

Methods: A psychometrist blinded to subject status assessed cognitive ability by the appropriate Wechsler scale and academic achievement by the Weschsler Individual Achievement Test. Behaviour rating scales including the Child Behaviour Checklist and the Teacher Report Form or the Youth Self Report were completed.

Results: 70 subjects (38 KS; 32 controls) with similar age (KS 11.4yrs; controls 12.2 yrs), gender, and socioeconomic status were assessed. 19 of 38 KS subjects had received IVIG and no differences were found in cognitive, academic or behavioural measures when compared to those that had not received IVIG. For KS and controls no differences were found in cognitive or academic measures; the mean scores were comparable and corresponded closely to national norms. Parents rated their KS children as having significantly more internalizing (p<0.03) and attentional (p<0.02) behaviour problems than their siblings and 34.2% felt the illness had a lasting effect on their child.

Implication: An acute episode of KS appears to have little objective effect on cognitive development and academic performance but may increase the risk of behavioural difficulties, specifically internalizing and attentional problems. This may be secondary to the disease process itself or heightened parental concern/anxiety. Further confirmation is required.