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Kawasaki Syndrome

Michael A. Davis, MD

Kawasaki syndrome (KS) is an acute, febrile, self-limited, infectious, multisystem vasculitis, which occurs in young children. Fever is often prolonged and coronary aneurysms may lead to myocardial infarction and death.

Epidemiology

KS has a peak incidence between 1 and 2 years of age. The disease is rare in children older than 8 years old, and it is uncommon before 3 months of age.

Boys are affected more often than girls by a ratio of 1.5 to 1. Japanese and Korean children are at greatest risk (145 per 100,000).

The rate for European children is 9 per 100,000, and the rate for African children is 20 per 100,000.

Pathophysiology

KS is a multisystem vasculitis with a predilection for the coronary arteries. KS is probably caused by an infectious agent, based on the acute febrile exanthematous character of the disorder and the occurrence of epidemics.

During the first 10 days of illness, an inflammatory infiltrate appears in the coronary arteries, with pancarditis and pericarditis. Death during this phase is usually caused by an arrhythmia, although fatal heart failure may sometimes occur.

Ten to 40 days from the onset of fever, the most common cause of death in untreated children is myocardial infarction caused by coronary aneurysms.

After 40 days, healing and stenosis of the post-aneurysmal coronary artery develops.

Clinical Manifestations

Abrupt onset of high but remittent fever between 38 and 41 degrees C is characteristic of KS.

Within 2 to 5 days, the child develops other diagnostic signs of KS: Conjunctival injection, mouth changes, an erythematous rash, changes in the hands and feet, and unilateral cervical lymphadenopathy.

Eye involvement consists of conjunctival injection and, often, photophobia.

The lips are initially bright red, progressing over 3 days to swelling, cracking, and bleeding. Prominent papillae on the tongue create a strawberry appearance, and the oral cavity and pharynx is diffusely erythematous.

The skin rash is deeply erythematous with slightly raised margins, varying in size from 2 to 3 mm papules to large plaques covering several centimeters. The rash often is urticarial and may be intensely pruritic. The rash frequently affects the face, often forming a mask-like area around the eyes, nose, and mouth. It may be distributed more prominently on the trunk or on the extremities.

Firm, indurative edema of the hands and feet and diffuse red-purple discoloration of palms and soles develop. The edema is sharply demarcated at the wrists and around the sides of the hands and feet.

Ten to 20 days after the onset of fever, in early convalescence, desquamation starts just under the fingernails and toenails and proceeds to involve the entire palm and sole.

Cervical lymph node involvement occurs in 50% of patients, manifesting as sudden onset of a firm swelling on one side of the neck.

Kawasaki Disease: Diagnostic Criteria

I. Fever for >5 days (usually >102EF)

II. At least four of five features

A. Bilateral conjunctival injection (bulbar. non-purulent)

B. Cervical adenitis (unilateral >1.5 cm diameter, non-fluctuant)

C. Rash (truncal. perineal accentuation, polymorphous but non-vesicular)

D. Inflamed oral mucosae (fissured lips, strawberry tongue)

E. Hands and feet inflammation (periungual peeling around 14-21 days)

III. No alternate diagnosis

IV. Fever plus 3/5 criteria are diagnostic when coronary abnormalities are present

Laboratory Findings

Aspirin

Cardiac Evaluation and Monitoring

 

Prognosis

KS usually is self-limited; however, cardiac damage may be serious. Twenty percent of all patients not treated with IVIG develop coronary artery aneurysms, appearing 7 days to 4 weeks after the onset of KS.

The risk of coronary aneurysms is reduced to 3% when IVIG is given. Patients who have coronary artery abnormalities are at risk for myocardial infarction, sudden death, and myocardial ischemia for at least 5 years; however, regression of aneurysms is usual.