Neonatal Kawasaki disease with multiple arterial aneurysms: a case report

Background Kawasaki disease (KD) is a medium vessel vasculitis that typically occurs in children aged between 6 months and 5 years. It is extraordinarily rare in the neonatal period. KD-related systemic artery aneurysms (SAAs) have never been reported in neonates. Case presentation A male infant was transferred to our institution for persistent high-grade fever lasting 16 days. Symptoms started at day 14 of life, and he was admitted to a children's hospital on the second day of fever. Physical examination at the time found no signs suggestive of KD. The only laboratory parameters which were of significance were values suggestive of systemic inflammation. However, his fever persisted and inflammatory markers continued to rise despite 2 weeks of antibiotic therapy. KD as a noninfectious cause of fever was considered when he came to our institution, and echocardiographic findings of left and right medium coronary artery aneurysms (CAAs) confirmed our suspicions. Full-body magnetic resonance angiography also revealed bilateral axillary artery aneurysms. Administration of intravenous gamma globulin resulted in rapid improvement. His fever resolved on the next day and CAAs and SAAs regressed to normal at 6 months and 3 months after diagnosis, respectively. Conclusion This unique case of incomplete KD highlights the importance of considering KD in neonates with unexplained prolonged fever and reinforces the need to remain vigilant for SAAs in KD.