Kawasaki Syndrome

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Basics

Description

  • 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

ALERT
KS should be considered in any child with extended high fever unresponsive to antibiotics or antipyretics, rash, and nonexudative conjunctivitis.

Epidemiology

Incidence
  • 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
    • 85% of cases are children <5 years of age and 50% <2 years of age.
    • Male-to-female ratio = 1.5:1

Prevalence
  • Highest to lowest prevalence: Asians > Black Americans > Hispanics > Caucasians
  • Seasonal variation: peaks in winter and early spring (January-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.

Genetics
  • 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 aneurisms are associated with variants in TGF-β signaling pathways.

Risk Factors

  • 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

General Prevention

No preventive measures available

-- To view the remaining sections of this topic, please or --

Basics

Description

  • 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

ALERT
KS should be considered in any child with extended high fever unresponsive to antibiotics or antipyretics, rash, and nonexudative conjunctivitis.

Epidemiology

Incidence
  • 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
    • 85% of cases are children <5 years of age and 50% <2 years of age.
    • Male-to-female ratio = 1.5:1

Prevalence
  • Highest to lowest prevalence: Asians > Black Americans > Hispanics > Caucasians
  • Seasonal variation: peaks in winter and early spring (January-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.

Genetics
  • 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 aneurisms are associated with variants in TGF-β signaling pathways.

Risk Factors

  • 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

General Prevention

No preventive measures available

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