- Kawasaki syndrome (KS) is a self-limited acute, febrile, systemic vasculitis of small- and medium-sized arteries that predominantly affects patients age 6 months to 5 years.
- The most prominent cause of acquired coronary artery disease in children in developed countries (1).
- Vasculitis of coronary arteries results in aneurysms/ectasia, leading to myocardial infarction (MI)/ischemia or sudden death
- System(s) affected: cardiovascular, gastrointestinal, hematologic/lymphatic/immunologic, musculoskeletal, nervous, pulmonary, renal/urologic, skin/exocrine
- Synonym(s): mucocutaneous lymph node syndrome (MCLS), infantile polyarteritis, Kawasaki disease
KS should be considered in any child with extended high fever unresponsive to antibiotics or antipyretics, rash, and nonexudative conjunctivitis.
- Worldwide: affects all races but most prevalent in Asia; Japan annual incidence rate 265/100,000 in children <5 years old
- In the United States, the annual incidence in children <5 years is 19/100,000. In comparison to Caucasians, African Americans have a 1.5 times risk, and Asian Americans have a 2.5 times increased risk. Highest state incidence is in Hawaii.
- Leading cause of acquired heart disease in children in developed countries
- Predominant age: 1 to 5 years, median age of diagnosis is 1.5 years of age.
- 85% of cases are children <5 years of age and 50% <2 years of age.
- Male-to-female ratio = 1.5:1
- Highest to lowest prevalence: Asians > Black Americans > Hispanics > Caucasians
- Seasonal variation: peaks in winter and early spring (January to March) in temperate places; peaks in summer in Asia
- Outbreaks at 2- to 3-year intervals
Etiology and Pathophysiology
- Infectious agent triggers abnormal inflammatory reaction in children with genetic predisposition.
- Acute KS causes a necrotizing arteritis in the smooth muscle layer of medium extraparenchymal arteries, destroying arterial walls into the adventitia, especially in coronary arteries.
- Inflammatory cells secrete cytokines (TNF-α), interleukins 1 and 6, and matrix metalloproteases that cause fragmentation of the internal elastic lamina.
- As the acute process resolves, active neutrophilic inflammatory cells are succeeded by a subacute/chronic, lymphocytic vasculitis; fibroblasts and monocytes cause tissue repair/remodeling that may cause vascular fibrosis and stenosis.
- Populations at higher risk and family link suggest a genetic predisposition.
- Siblings of patients in Japan have a 10- to 30-fold increased risk, and >50% develop KS within 10 days of first case; increased occurrence of KS in children whose parents also had illness in childhood
- Single-nucleotide polymorphisms in six different genes have been implicated in KS (Fcγ receptor 2A, CASP3, HLA class II, B-cell lymphoid kinase, IPTKC, CD40).
- Coronary aneurysms are associated with variants in TGF-β signaling pathways.
- Male to female prevalence 1.5:1 in United States
- Black Americans at 1.5 times risk; Asian Americans at 2.5 times risk
- Sibling with Kawasaki
No preventive measures available
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