Kawasaki disease

Kawasaki disease is an acute, necrotizing vasculitis of unknown etiology. The condition primarily affects children under the age of five and is more common among those of Asian descent. The disease is characterized by a high fever, desquamative rash, conjunctivitis, mucositis (e.g., “strawberry tongue”), cervical lymphadenopathy, as well as erythema and edema of the distal extremities. However, coronary artery aneurysms are the most concerning possible manifestation as they can lead to myocardial infarction or arrhythmias. Kawasaki disease is a clinical diagnosis, further supported by findings such as elevated ESR or evidence of cardiac involvement on echocardiography. Treatment with IV immunoglobulins and high-dose aspirin is essential and should be initiated immediately after diagnosis.

• Sex: ♂ > ♀ (1.5:1) ^[1]
• Age: : primarily children < 5 years (most common cause of acquired coronary artery disease in children) ^[2][3]
• Peak incidence: occurs mostly in late winter and spring
• Prevalence ^[2]
  • Approx. 20 per 100,000 children
  • Highest rate in children of Asian and Pacific-Islander descent
• Mortality: < 0.5% ^[4]

Epidemiological data refers to the US, unless otherwise specified.

• The exact cause of Kawasaki disease remains uncertain.
• However, it is associated with infectious and genetic factors (the prevalence is higher in patients of Asian descent and in siblings of affected children). ^[5]

• Clinical diagnosis requires fever for at least 5 days and one of the following: ^[6]
  • ≥ 4 other specific symptoms
  • < 4 specific symptoms and involvement of the coronary arteries
• Specific symptoms include:
  • Erythema and edema of hands and feet, including the palms and soles (the first week)
  • Possible desquamation of fingertips and toes after 2–3 weeks
  • Polymorphous rash, originating on the trunk
  • Painless bilateral “injected” conjunctivitis without exudate
  • Oropharyngeal mucositis
    • Erythema and swelling of the tongue (strawberry tongue)
    • Cracked and red lips
  • Cervical lymphadenopathy (mostly unilateral)
• Nonspecific symptoms may precede the onset of Kawasaki disease (e.g., diarrhea, fatigue, abdominal pain, arthritis, hoarseness, breathing difficulties) ^[7]

Always consider Kawasaki disease in small children with a rash and high fever unresponsive to antibiotics.

“CRASH and BURN”: Conjunctivitis, Rash, Adenopathy, Strawberry tongue, Hands and feet, and BURN (fever ≥ 5 days) are the most common features of Kawasaki disease.

Kawasaki disease is a clinical diagnosis (see “Clinical features” above) which is supported by the following diagnostic findings:

• Laboratory findings
  • ↑ ESR and CRP
  • Leukocytosis
  • Thrombocytosis
  • ↑ AST, ALT
• Echocardiography
  • For evaluating coronary artery aneurysms
  • Minimal evaluation: should be performed at diagnosis, at 2 weeks, and at 6–8 weeks after onset ^[8]

• IV immunoglobulin (IVIG)
  • High single-dose to reduce the risk of coronary artery aneurysms
  • Most effective if given within the first 10 days following disease onset ^[9]
• High-dose oral aspirin ^[10][11]
• IV glucocorticoids: may be considered in addition to standard treatment, esp. in cases of treatment-refractory disease, as they lower the risk of coronary involvement

To avoid the risk of Reye syndrome, children should not be treated with aspirin, especially if a viral infection is suspected. Kawasaki disease is an exception to this rule.

• Coronary artery aneurysm ; ^[8]
  • The risk of aneurysms is highest during the second and third weeks following symptom onset. ^[8]
  • Rupture or thrombosis of the aneurysm can be lethal.
• Myocardial infarction
• Myocarditis
• Ventricular dysfunction
  • Most commonly occurs within the first 2 weeks of onset of Kawasaki disease ^[12]
  • Often seen in infants with untreated Kawasaki disease ^[13]
  • Most commonly associated with lymphocytic myocarditis ^[12][14]
  • Manifests with symptoms (e.g., tachypnea or diaphoresis with feeding, exertional dyspnea; ) and physical examination findings of congestive heart failure (e.g., hepatomegaly, S₃ gallop, rales or crackles on lung auscultation) ^[15]
  • Increased risk of sudden death ^[13]
• Arrhythmias

We list the most important complications. The selection is not exhaustive.