Ever heard about this disease? though the name like Japanese motorcycle brand, but this disease is serious and could cause death. The disease probably has existed for a long time, but it was not recognized as a separate entity until Dr Tomisaku Kawasaki first described it in 1967. Kawasaki disease was later reported in the English-language literature in 1974. Kawasaki disease is an acute febrile illness associated with multiorgan vasculitis of unknown etiology that primarily affects infants and children.

Kawasaki syndrome is characterized by fever; rash; swelling of the feet and hands; irritation; redness of the whites of the eyes; swollen lymph glands in the neck; and irritation and inflammation of the mouth, lips, and throat. The histologic changes of Kawasaki disease are consistent with a systemic vasculitis affecting medium and small arteries (and the veins to a lesser extent), with inflammatory lesions in all organs.

The annual incidence in the US is approximately 6-11 cases per 100,000 in children younger than 5 years. The peak incidence is in those aged 18-24 months. About 80% of the cases of Kawasaki disease have been reported in patients younger than 5 years.

Kawasaki disease has been reported throughout the world and predominantly affects children younger than 5 years. A slightly increased prevalence is seen in late winter and spring.

Mortality/Morbidity
• The mortality rate was more than 1% in the 1970s and decreased to less than 0.4% in the 1990s.
• In Japan and the US, Kawasaki disease is a leading cause of acquired heart disease in children. The heart may be affected in as many as 20% of children who develop Kawasaki disease. Kawasaki disease damages the coronary arteries (resulting in aneurysms) and myocardial muscles.
• Most deaths from Kawasaki disease result from acute-phase coronary disease or cardiac complications.

Japanese surveys of Kawasaki disease have documented a total of 848 patients as of 1992, with a male-to-female ratio of 1.3-1.5:1. In the US, 80% of the cases of Kawasaki disease manifest by the time the patient is aged 5 years.

The etiology of Kawasaki disease is unknown. Kawasaki disease does not appear to be hereditary or contagious. Because the illness frequently occurs in outbreaks, an infectious agent is the likely cause. Standard laboratory studies have been unsuccessful in identifying a specific agent. Although the initiating agent has not been identified yet, immune-system activation has been documented in the acute stage. Various secreted cytokines may target the vascular endothelial cells, producing cell-surface neoantigens. Antibodies produced against these antigens may target the vascular endothelium, resulting in a cascade of events that result in vascular damage.

Kawasaki disease manifests as an acute febrile illness that can be delineated into acute, subacute, and convalescent phases. The acute phase lasts 7-14 days, the subacute phase extends from days 10-24, and the convalescent stage typically lasts 6-8 weeks.

The Japan Kawasaki Disease Research Committee and subsequently the American Heart Association have developed clinical criteria for this disease. The criteria for a diagnosis of Kawasaki disease are shown below.
• A fever that lasts for a minimum of 5 days
• The presence of 4 of the following 5 conditions:
1. Bilateral conjunctival injection
2. Changes of the mucosae of the oropharynx, including an injected pharynx, an injected and/or dry fissured lips, and a strawberry tongue
3. Changes of the peripheral extremities, such as edema and/or erythema of hands and/or feet, and desquamation (usually beginning periungually)
4. Rash (primarily truncal), which is polymorphous but nonvesicular
5. Cervical lymphadenopathy
• Illness not explained by other known disease processes

Additional findings not included in the major diagnostic criteria are often present in patients with Kawasaki disease. These are subdivided into cardiac, noncardiac, and laboratory findings.

Cardiovascular manifestations can be prominent in the acute phase of the illness and are the leading cause of morbidity and mortality. Pancarditis may occur. Coronary aneurysms are believed to occur in 20-25% of children with Kawasaki disease. Involvement of the left coronary artery is more common than involvement of the right coronary artery. Patients with giant aneurysms (internal diameter of at least 8 mm) have the worst prognosis and are at greatest risk of developing thrombosis, stenosis, and myocardial infarction. Long-term follow-up studies demonstrate the resolution of coronary aneurysms within 5-18 months in approximately 50% of patients. Other cardiac manifestations of Kawasaki disease include myocarditis, pericarditis with pericardial effusions, wall-motion abnormalities, valvulitis or papillary muscle dysfunction, and acute mitral regurgitation secondary to rupture of the cordae tendineae.

Regarding noncardiac findings, Kawasaki disease is a multiorgan disease. During the acute phase, children may develop aseptic meningitis, hyperemic tympanic membrane, or uveitis. Neurologic complications, which include facial nerve palsy, seizures, and ataxia cerebral infarctions, are rare. Other common features include diarrhea, vomiting, abdominal pain, and pneumonitis. Gallbladder hydrops (acute acalculous distention of the gallbladder) may occur in the first 2 weeks of illness, it may be the result of the extension of periportal inflammation to the cystic duct, and it is typically self-limited. Arthritis and arthralgia are common in the acute phase. Findings that include erythema and induration at the site of recent Bacille Calmette-Guérin vaccination, testicular swelling, and peripheral gangrene also have been reported in patients with this disease.

In terms of laboratory findings, leukocytosis with left shift is common in the acute phase. Marked hypercoagulability, an elevated erythrocyte sedimentation rate, elevated liver transaminase levels, and sterile pyuria are also seen.
The ECG is usually normal.
The number of reports of atypical Kawasaki disease is increasing. In these cases, the criteria are not fulfilled, and yet, children develop coronary artery abnormalities. Intravenous (IV) gamma globulin is often administered to patients in whom Kawasaki disease is strongly suspected on the basis of the clinical findings.

In the absence of a specific diagnostic test, Kawasaki disease is a clinical diagnosis based on characteristic features of the history and on physical findings.