Kawasaki Disease

Kawasaki disease (KD) is an acute, self-limited vasculitis of medium-sized arteries, predominantly affecting children under 5 years, characterized by fever, mucocutaneous inflammation, and risk of coronary artery aneurysms.

Definition

Epidemiology

Primarily affects children under 5 years, peak incidence at 18–24 months
Higher incidence in boys than girls (male:female ratio ~1.5:1)
Most common in East Asian populations, especially Japan and Korea
Seasonal variation: more cases in winter and early spring
Leading cause of acquired heart disease in children in developed countries

Etiology

Exact cause unknown; likely triggered by infectious agents in genetically predisposed children
Immune system dysregulation leading to systemic vasculitis
Possible involvement of viral or bacterial superantigens
Genetic susceptibility: variations in ITPKC, CASP3, and other immune-related genes
Environmental factors may contribute to outbreak patterns

Pathophysiology

Systemic inflammation of medium-sized arteries, especially coronary arteries
Endothelial cell activation leads to vascular damage and aneurysm formation
Inflammatory cytokines (IL-1, IL-6, TNF-alpha) mediate tissue injury
Immune cell infiltration in vessel walls (neutrophils, lymphocytes) leads to vasculitis
Prolonged inflammation may result in coronary artery aneurysms, thrombosis, or myocardial ischemia
Systemic manifestations due to widespread vascular involvement