Incomplete Kawasaki Disease With Rapid Coronary Aneurysm Progression

Giant coronary artery aneurysms occur in 0.16% to 1% of children with Kawasaki disease; in incomplete disease, the incidence is unclear, but coronary lesion risk is similar or higher.

We report a case of incomplete Kawasaki disease in a 2-year-old boy that, despite early treatment, progressed to severe coronary involvement. Initial echocardiography was normal, but repeat imaging revealed diffuse giant coronary artery aneurysms (left anterior descending artery, right coronary artery, left circumflex artery). He required multiple anti-inflammatory therapies (intravenous immunoglobulin, infliximab) and lifelong antithrombotic management with aspirin and anticoagulation.

This case illustrates the challenges of diagnosing and managing incomplete Kawasaki disease, particularly when initial symptoms overlap with common viral infections and when early echocardiography is normal. Early risk stratification, guided by age and initial coronary z-scores, is critical for identifying high-risk patients who may benefit from adjunctive therapies. It demonstrates that severe coronary involvement can progress even after timely treatment and underscores the importance of close monitoring.

Incomplete Kawasaki disease can rapidly cause giant coronary aneurysms despite timely treatment, making serial echocardiography essential.