Clinical characteristics and serum N-terminal pro-brain natriuretic peptide as a diagnostic marker of Kawasaki disease in infants younger than 3 months of age

PURPOSE: The incidence of Kawasaki disease (KD) is rare in young infants (less than 3 months of age), who present with only a few symptoms that fulfill the clinical diagnostic criteria. The diagnosis for KD can therefore be delayed, leading to a high risk of cardiac complications. We examined the clinical characteristics and measured the serum levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) levels of these patients for assessing its value in the early detection of KD. METHODS: We retrospectively reviewed the data of young infants diagnosed with KD from 2004 to 2012. The control group included 20 hospitalized febrile patients. Laboratory data, including NT-proBNP were obtained for each patient in both groups. RESULTS: Incomplete KD was observed in 21/24 patients (87.5%). The mean fever duration on admission was 1.36±1.0 days in the KD group. Common symptoms included erythema at the site of Bacille Calmette-Guerin inoculation (70.8%), skin rash (50.0%), changes of oropharyngeal mucosa (29.1%), and cervical lymphadenopathy (20.8%). The mean number of major diagnostic criteria fulfilled was 2.8±1.4. Five KD patients (20.8%) had only one symptom matching these criteria. The incidence of coronary artery complications was 12.5%. The mean serum NT-proBNP level in the acute phase, in the KD and control groups, were 4,159±3,714 pg/mL and 957±902 pg/mL, respectively, which decreased significantly in the convalescent phase. CONCLUSION: Incomplete KD was observed in 87.5% patients. Serum NT-proBNP might be a valuable biomarker for the early detection of KD in febrile infants aged <3 months.