Neonatal Kawasaki Disease with Progressive Coronary Artery Aneurysms Requiring Infliximab Therapy: A Case Report

Kawasaki disease (KD) presents with medium vessel vasculitis. The condition is rare in newborns. We present a previously healthy 4-week-old baby with fever and evolving mucocutaneous involvement. Infectious workup was negative, but inflammatory markers (C-reactive protein, leucocytosis and thrombocytosis) progressively worsened. Serial echocardiography (initially normal) showed a small right coronary artery aneurysm (1.89 mm, z-score +2.77). Treatment was initiated with intravenous immunoglobulin (IVIG), aspirin and corticosteroids. Though clinical improvement was noted, repeat echocardiography demonstrated involvement of the left anterior descending artery (1.69 mm, z-score +2.65) and left circumflex artery (1.62 mm, z-score +2.72). Coronary artery disease progression occurred despite fever resolution with IVIG and steroids, prompting escalation to infliximab due to serial echocardiographic worsening. Subsequent follow-up showed regression and resolution of coronary dilation. This report emphasises the need for consideration of an alternative diagnosis if workup for sepsis-like illness does not reveal a clear pathogenic aetiology. Rapid and optimal escalation of therapy with immunomodulators plays a crucial role in halting progression and facilitating resolution of coronary artery disease.