Kawasaki disease, also known as Kawasaki syndrome, is a vasculitis that occurs mainly in children under 5 years of age and primarily affects medium-sized arteries, especially the coronary arteries.
It is a nonspecific disease that can affect mucous membranes (oral, nasal, conjunctival), lymph nodes, the lining of blood vessels, and the heart.
More than 30% of children with Kawasaki disease show signs of coronary artery vasculitis.
Coronary artery vasculitis (inflammation of blood vessels) can lead to aneurysms, which may cause myocardial infarction even in young children.
The cause of Kawasaki disease has not yet been determined.
Although it is not contagious, more than 40% of diagnosed children present with concurrent viral respiratory infections.
It is believed that one or more as-yet-unidentified infectious agents may trigger an intense inflammatory response in genetically susceptible individuals.
The disease is considered to have an autoimmune component that develops due to external factors affecting the mucous membranes, lymph nodes, blood vessels, and heart.
Kawasaki disease occurs most frequently in young children, with 80% of patients being under 5 years of age and 50% under 2 years.
It has an approximate incidence of 100 to 150 cases per 100,000 children under 5 years old. Its prevalence is low outside East Asian countries (especially Japan), although it is more common in children of Asian descent in other regions (particularly Japanese).
It is more frequent in boys than in girls (1.5:1).
Kawasaki disease is characterized by a persistent high fever (lasting more than two weeks) that does not respond to normal doses of paracetamol or ibuprofen.
The disease evolves through three phases:
Less common symptoms include irritability, abdominal pain, hepatitis, joint pain, aseptic meningitis, myocarditis, valvular insufficiency, epididymitis, and aortic aneurysms.
In infants under 6 months, incomplete forms without all the classic criteria may occur.
The diagnosis of Kawasaki disease is primarily clinical. A history of prolonged high fever, rash with joint pain, and intensely red mucous membranes suggests the diagnosis.
According to the American Heart Association (AHA), the patient must have fever for 5 or more days plus at least 4 of the following findings:
When not all criteria are met—especially in children under 6 months—additional tests are performed to detect vasculitis, such as an electrocardiogram or echocardiogram.
Common complementary studies include:
Children suspected of having Kawasaki disease should be hospitalized, and treatment should be coordinated between pediatric cardiologists and infectious disease specialists.
Early diagnosis and prompt treatment determine the extent of damage to the coronary arteries and heart.
The standard treatment is high-dose intravenous immunoglobulin (IVIG), with effects typically observed within the first 24 hours.
Aspirin is used as adjunctive therapy, while IVIG remains the most effective treatment.
In difficult cases, corticosteroids, tumor necrosis factor inhibitors (e.g., infliximab), interleukin-1 inhibitors (e.g., anakinra), or cyclosporine may be used.
In addition to aspirin as an antiplatelet agent, anticoagulants are administered to prevent thrombosis and myocardial infarction. The most commonly used drugs are warfarin and low-molecular-weight heparins (LMWH).
With early and appropriate treatment, full recovery is the norm. However, about 2% of patients die from complications of coronary vasculitis.
The most frequent complication is coronary vasculitis with aneurysm formation, which may lead to acute myocardial infarction, arrhythmias, or sudden death, particularly during the thrombocytosis phase.
Small aneurysms tend to resolve spontaneously, but larger ones can persist and require lifelong monitoring.
Therefore, all affected patients should undergo regular cardiac evaluations, including an electrocardiogram every one to two years. Cardiac follow-up includes serial echocardiograms to monitor aneurysm formation and cardiac function.
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