Kawasaki syndrome is a potentially fatal inflammatory disease that affects several organ systems in the body, including the heart, circulatory system, mucous membranes, skin, and immune system. Infants and children are at highest risk (80% are children under 4), but adults have also been diagnosed with the condition. Its cause is unknown.
Nearly twice as common among men, the disease affects Asians more often thaneither blacks or whites, but it doesn't seem to be found in any one particular part of the world. Although the disease usually occurs in single cases, itsometimes affects several members of the same family and occasionally occursin small epidemics.
The specific cause of Kawasaki syndrome is unknown, although the disease resembles infections in many ways. Kawasaki syndrome may represent an allergic reaction or another unusual response to certain infections. Some researchers think that the syndrome may be caused by the interaction of an immune cell (called the T cell) with certain poisons produced by bacteria.
The symptoms of Kawasaki disease include a fever and a rash that spreads over the patient's chest and genital area. The fever is followed by peeling of the skin beginning at the fingertips and toenails. In addition to the body rash, the patient's lips become very red and the tongue takes on a "strawberry" appearance. The palms, soles, and mucous membranes that line the eyelids and cover the exposed portion of the eyeball become purplish-red and swollen. The lymph nodes in the patient's neck may also become swollen. These symptoms may last from two weeks to three months, with relapses in some patients.
In addition to the major symptoms, about 30% of patients develop joint painsor arthritis, usually in the large joints of the body. Others develop pneumonia, diarrhea, dry or cracked lips, jaundice, or an inflammation of the membranes covering the brain and spinal cord (meningitis). A few patients develop symptoms of inflammation in the liver, gallbladder, lungs, or tonsils. About 20% of patients with Kawasaki syndrome develop complications of the cardiovascular system. These complications include inflammation of the heart tissue (myocarditis), disturbances in heartbeat rhythm (arrhythmias), and areasof blood vessel dilation (aneurysms). Other patients may develop inflammation of an artery in their arms or legs. Complications of the heart or arteries begin to develop around the tenth day after infection. The specific causes of these complications are not yet known.
Because Kawasaki syndrome is primarily a disease of infants and young children, the disease is most likely to be diagnosed by a pediatrician. The doctor will first rule out other diseases that cause fever and skin rashes, includingscarlet fever, measles, Rocky Mountain spotted fever, toxoplasmosis (a disease carried by cats), juvenile rheumatoid arthritis, and a blistering and inflammation of the skin caused by reactions to certain medications.
Chest x ray may show enlargement of the heart (cardiomegaly). Urine may showthe presence of pus or an abnormally high level of protein. An electrocardiogram may show changes in the heartbeat rhythm. In addition to these tests, itis important to take a series of echocardiograms during the course of the illness because 20% of Kawasaki patients will develop coronary aneurysms or arteritis that will not appear during the first examination.
Kawasaki syndrome is usually treated with a combination of aspirin to controlthe patient's fever and skin inflammation, and high doses of intravenous immune globulin to reduce the possibility of coronary artery complications. Somepatients with heart complications may be treated with drugs that reduce blood clotting or may receive corrective surgery. Follow-up care includes two tothree months of monitoring with chest x rays, electrocardiography, and echocardiography. Treatment with aspirin is often continued for several months.
Most patients with Kawasaki syndrome will recover completely, but about 1-2%will die as a result of blood clots forming in the coronary arteries or as aresult of a heart attack. Deaths are sudden and unpredictable. Almost 95% offatalities occur within six months of infection, but some have been reportedas long as 10 years after.