Background: Most common complications of Kawasaki disease (KD) are coronary artery abnormalities. The incidence of coronary artery aneurysms for the treatment beyond day 10 of illness are three times greater than the treatment within 10 days. The efficacy of treating patients with KD by using IVIG after 10 days of illness is unknown.
Objectives: We analyzed delayed-diagnosis KD patients' clinical manifestations and outcomes after treatment with IVIG.

Methods: A retrospective review was made of the medical records of KD patients at King Chulalongkorn hospital between 1996 and 2007. Delayed diagnosis of KD was defined as the diagnosis that was made 10 days after the onset of the fever.

Results: Twenty-seven (20 males and 7 females) of a total of 170 KD children were delayed diagnosed. Of which 11 cases were incomplete KD, eight cases were complete, and eight cases were atypical KD. Twenty cases (74.1%) had the age of over one year. There were 16 cases (59.3%) with coronary artery abnormalities at the time of diagnosis. Mean durations of fever were 14.07 + 3 days. Seventeen patients were treated with IVIG. There was no statistical difference between IVIG group and non-IVIG group in terms of coronary arteries regression. However, the patients receiving IVIG treatment had significantly relieved the clinical symptoms.

Conclusions: Patients with delayed diagnosis of KD had high incidence of coronary abnormalities. There was no statistical difference in terms of coronary arteries regression between IVIG group and non-IVIG group.