A Clinical Study of Atypical Kawasaki Syndrome: A Comparison with Typical Kawasaki Syndrome

Abstract

The diagnosis of Kawasaki syndrome (KS) is based on the clinical features. Not all KS patients fulfill the classic diagnostic criteria and diagnosis is often based on the finding of coronary aneurysm by echocardiography. Children with KS manifested by fever and fewer than four other criteria, so called atypical KS, are known to be at high risk for coronary aneurysms. This study was performed to evaluate clinical and laboratory features including coronary artery involvement in atypical KS in comparison with typical KS. Data were reviewed retrospectively in 72 patients with KS. According to the diagnostic criteria, these patients were divided into 30 of atypical KS and 42 of typical KS. The mean duration of fever was 5.8±·4.3 days in atypical KS(6.7±4.8 days in typical KS, p0.05). The incidence of each diagnostic criteria in atypical KS were as follows: conjunctival injection 80%, changes of oral mucosa 73.3%, rash 43.3%, changes of hands and feet 36.6%, and cervical lymphadenopathy 23.3%. Erythema at the site of BCG was observed in 7 of 13 patients with atypical KS who were less than 25 months old. There was no significant difference in the incidence of other clinical features such as aseptic meningitis, gallbladder hydrops, arthralgia and arthritis. Echocardiographic abnormalities were observed in 20% of atypical KS (aneurysm 6.7% and ectasia 13.3%) and 47.7% of typical KS (aneurysm 14.3% and ectasia 33.4%) during the subacute phase. Follow-up echocardiographic studies during convalescent phase revealed regression of coronary artery abnormalities: 7.7% of atypical KS (aneurysm 0%, ectasia 7.7%) and 14.7% of typical KS (aneurysm 2.9% and ectasia 11.8%). Statistical analysis determined no significant difference in the incidence of coronary artery involvement between atypical and typical KS. In conclusion, atypical KS emphasize the index of suspicion of KS with respect to the coronary artery involvement.