Which of the following is the most serious systemic complication associated with Kawasaki disease?

• A. Renal
• B. Cardiac
• C. Pulmonary
• D. Hepatic

Answer: (B)

Kawasaki disease is a pediatric medium‑vessel vasculitis, and while it can involve multiple organ systems, the heart is the most concerning site because of the risk to the coronary arteries. The inflammation can damage the coronary arteries, leading to aneurysm formation. These aneurysms can then thrombose or progress to stenosis, causing myocardial ischemia or infarction, which can occur during the acute illness or later in childhood or adolescence. Because of this high risk, cardiac involvement defines the seriousness of the condition and drives urgent treatment. Prompt IVIG administration markedly lowers the likelihood of coronary aneurysm formation, and aspirin is used for its anti-inflammatory and antiplatelet effects. Regular echocardiographic monitoring tracks coronary artery status over time. While renal, hepatic, or pulmonary abnormalities can occur, they do not carry the same potential for sudden, life-threatening cardiac events as coronary artery disease does.