What is Kawasaki Disease

Kawasaki (KAH'wah-SAH'ke) disease is a children's illness. It's also known as Kawasaki syndrome or mucocutaneous (mu"ko-ku-TA'ne-us) lymph node syndrome. It and acute rheumatic (roo-MAT'ik) fever are the two leading causes of acquired heart disease in children in the United States.

Kawasaki disease is an acute, self-limited vasculitis of unknown etiology that occurs predominantly in infants and young children. First described in Japan in l967 by Tomisaku Kawasaki, the disease is now known to occur in both endemic and community-wide epidemic forms in the Americas, Europe, and Asia in children of all races.¹ Kawasaki disease is characterized by fever, bilateral nonexudative conjunctivitis, erythema of the lips and oral mucosa, changes in the extremities, rash, and cervical lymphadenopathy. Coronary artery aneurysms or ectasia develop in 15% to 25% of untreated children with the disease and may lead to myocardial infarction (MI), sudden death, or ischemic heart disease.^2,3 In the United States, Kawasaki disease has surpassed acute rheumatic fever as the leading cause of acquired heart disease in children.⁴ Treatment of Kawasaki disease in the acute phase is directed at reducing inflammation in the coronary artery wall and preventing coronary thrombosis, whereas long-term therapy in individuals who develop coronary aneurysms is aimed at preventing myocardial ischemia or infarction.

A new feature of these recommendations is an algorithm for the evaluation and treatment of patients in whom incomplete or atypical Kawasaki disease is suspected (refer to Criteria for Treatment of Kawasaki Disease later in this statement and Figure 1). We attempt to summarize the current state of knowledge of the management of patients with Kawasaki disease. The recommendations are evidence based and derived from published data wherever possible. The levels of evidence on which recommendations are based are classified as follows: level A (highest), multiple randomized clinical trials; level B (intermediate), limited number of randomized trials, nonrandomized studies, and observational registries; and level C (lowest), primarily expert consensus.

What Happens to those that get Kawasaki Disease (KD for short)

The symptoms of Kawasaki disease include...

• fever
• rash
• swollen hands and feet
• irritation and redness of the whites of the eyes
• swollen lymph glands in the neck
• irritation and inflammation of the mouth, lips and throat

Doctors don't know what causes Kawasaki disease, but it doesn't seem to be hereditary or contagious. Scientists who've studied it think the evidence strongly suggests it's caused by an infectious agent such as a virus. It's very rare for more than one child in a family to develop Kawasaki disease. Less than 2 percent of children have another attack of Kawasaki disease.

In as many as 15 to 25 percent of the children with Kawasaki disease, the heart is affected. The coronary arteries or the heart muscle itself can be damaged.

How does Kawasaki disease affect the heart?

The coronary arteries are most often affected. Part of a coronary wall can be weakened and balloon (bulge out) in an aneurysm. A blood clot can form in this weakened area and block the artery, sometimes leading to a heart attack. The aneurysm can also burst, but this rarely happens.

Other changes include inflammation of the heart muscle (myocarditis) or the sac surrounding the heart (pericarditis). Arrhythmias (abnormal heart rhythms) or abnormal functioning of some heart valves also can occur.

Usually all the heart problems go away in five or six weeks, and there's no lasting damage. Sometimes coronary artery damage persists, however.

An arrhythmia or damaged heart muscle can be detected using an electrocardiogram (EKG). An echocardiogram (or "echo") is used to look for possible damage to the heart or coronary arteries.

How is Kawasaki disease treated?

Even though the cause of Kawasaki disease is unknown, certain medicines are known to help. Aspirin is often used to reduce fever, rash, joint inflammation and pain, and to help prevent blood clots from forming. Another medicine, intravenous gamma globulin,(also know as IVIG) can decrease the risk of developing coronary artery abnormalities when given early in the illness.

Figure 1. Evaluation of suspected incomplete Kawasaki disease. (1) In the absence of gold standard for diagnosis, this algorithm cannot be evidence based but rather represents the informed opinion of the expert committee. Consultation with an expert should be sought anytime assistance is needed. (2) Infants 6 months old on day 7 of fever without other explanation should undergo laboratory testing and, if evidence of systemic inflammation is found, an echocardiogram, even if the infants have no clinical criteria. (3) Patient characteristics suggesting Kawasaki disease are listed in Table 1. Characteristics suggesting disease other than Kawasaki disease include exudative conjunctivitis, exudative pharyngitis, discrete intraoral lesions, bullous or vesicular rash, or generalized adenopathy. Consider alternative diagnoses (see Table 2). (4) Supplemental laboratory criteria include albumin 3.0 g/dL, anemia for age, elevation of alanine aminotransferase, platelets after 7 d 450 000/mm3, white blood cell count 15 000/mm3, and urine 10 white blood cells/high-power field. (5) Can treat before performing echocardiogram. (6) Echocardiogram is considered positive for purposes of this algorithm if any of 3 conditions are met: z score of LAD or RCA 2.5, coronary arteries meet Japanese Ministry of Health criteria for aneurysms, or 3 other suggestive features exist, including perivascular brightness, lack of tapering, decreased LV function, mitral regurgitation, pericardial effusion, or z scores in LAD or RCA of 2–2.5. (7) If the echocardiogram is positive, treatment should be given to children within 10 d of fever onset and those beyond day 10 with clinical and laboratory signs (CRP, ESR) of ongoing inflammation. (8) Typical peeling begins under nail bed of fingers and then toes.

Recommendations for initial evaluation, treatment in the acute phase, and long-term management of patients with Kawasaki disease are intended to assist physicians in understanding the range of acceptable approaches for caring for patients with Kawasaki disease. Where published data do not define well the best medical practices, our report provides practical interim recommendations. Ultimately, management decisions must be individualized to a patient’s specific circumstances.