Kawasaki Syndrome

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  • 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 and is the most prominent cause of acquired coronary artery disease in pediatric populations.
    • Vasculitis of coronary arteries resulting in aneurysms/ectasia, further 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 of age
  • 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
    • 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 > African Americans > Hispanics > Caucasians
  • Seasonal variation: increased in winter and early spring in temperate places, summer in Asia, and outbreaks at 2- to 3-year intervals

Etiology and Pathophysiology

  • Acute KS causes a necrotizing arteritis in the smooth muscle layer of medium extraparenchymal arteries that destroys arterial walls into the adventitia, especially in coronary arteries.
  • Inflammatory cells in the media secrete cytokines (TNF-α), interleukins 1 and 6, and matrix metalloproteases that cause fragmentation of the internal elastic lamina.
  • A prominence of IgA plasma cells and IgA deposits are characteristic features and may be found in the lungs.
  • 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.
  • Unknown; believed to be an exaggerated immune response to infectious agent due to the acute, self-limited nature; community-wide outbreaks; age distribution; seasonality; and laboratory features indicating respiratory route of entry

  • 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
  • Populations at higher risk and family link suggest a genetic predisposition.
  • 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 aneurisms are associated with variants in TGF-β signaling pathways.

General Prevention

No preventive measures available

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