Kawasaki disease is an inflammatory illness in children that involves the body's blood vessels. The hallmarks of the disease are high fever, swollen glands, and a rash, and it may lead to complications affecting the heart.
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What Is Kawasaki Disease?
For children in the United States, Kawasaki disease is the leading cause of acquired heart disease, that is, heart disease that is not present at birth but develops later in life. In 1967, the Japanese pediatrician Tomisaku Kawasaki first described the illness. He called it mucocutaneous (myoo-ko-kyoo-TAY-nee-us) lymph node syndrome, but today, it is better known as Kawasaki disease. Even after many years of research, the cause of this disease remains unknown, but doctors suspect that an infectious microorganism * may trigger the onset of inflammation in the body. Kawasaki disease sometimes occurs in outbreaks, often in late winter or spring, and can resemble diseases like measles or scarlet fever * , which suggests a possible link to an infectious organism.
Kawasaki disease can cause inflammation of blood vessels, mucous membranes (moist linings of the mouth, nose, eyes, and throat), lymph nodes * , and the heart. Although it eventually clears up on its own, if left untreated it can damage the blood vessels that supply the heart muscle. Kawasaki disease is associated with a 1 in 5 risk of coronary aneurysms * . This blood vessel damage can lead to a heart attack, especially in very young children.
How Common Is It?
As many as 3,500 children are hospitalized with Kawasaki disease each year in the United States. Four out of five children who get the disease are less than 5 years old, and it is extremely rare in children older than 15. Kawasaki disease develops in boys about twice as often as in girls. It is more common in children of Asian descent, though it occurs in all races.
* microorganism is a tiny organism that can be seen only using a microscope. Types of microorganisms include fungi, bacteria, and viruses.
* scarlet fever is an infection that causes a sore throat and a rash.
* lymph (LIMF) nodes are small, bean-shaped masses of tissue that contain immune system cells that fight harmful microorganisms. Lymph nodes may swell during infections.
* coronary aneurysm (KOR-uh-nair-e AN-yuh-rih-zum) is an abnormal stretching and weakening of a blood vessel that supplies blood to the heart. If it breaks open, it may cause serious damage to the heart, sometimes leading to death.
Is It Contagious?
The disease itself has not been proved to be contagious. Doctors suspect, however, that an infectious microorganism may trigger it and that the organism might be contagious. Nonetheless, it is rare for more than one child in a family to have Kawasaki disease.
What Are the Signs and Symptoms
of the Disease?
Kawasaki disease has distinctive features. A high fever, often more than 104 degrees Fahrenheit, usually appears first and lasts for at least 5 days. Afterward, signs of Kawasaki disease show up in stages and may include a red rash over the entire body, cracked lips, inflamed lining of the mouth, and a red, swollen tongue. Infected children also may have reddened and swollen hands, feet, fingers, and toes, with peeling skin; conjunctivitis in both eyes; sore, stiff joints; and swollen lymph nodes in the neck. Some children experience abdominal pain and diarrhea as well. The earliest phase of the disease, including fever and rash, usually lasts 10 to 14 days. The later phase, with peeling skin and slowly easing joint pain, can persist up to 2 months. Heart problems, if they occur, are more likely to show up during this time.
Making the Diagnosis
No single laboratory test can identify Kawasaki disease, so doctors make the diagnosis based on the child's symptoms and a physical examination: 5 days of high fever, accompanied by most of the associated telltale signs mentioned earlier. Blood tests help support the diagnosis and include tests to determine the numbers of white blood cells (cells that respond to infection) and platelets * and tests that detect inflammation in the body. Echocardiograms * and chest X rays are done to look for evidence of damage to the heart and coronary arteries * .
How Do Doctors Treat Kawasaki Disease?
Kawasaki disease is treated in the hospital. Children typically are given high doses of aspirin to decrease inflammation, prevent blood clots * in the heart's blood vessels, and lessen fever and joint pain. A one-time dose of intravenous gamma globulin * also is given to lower the risk of heart problems, particularly coronary aneurysms. (Even though aspirin is an important part of the treatment for Kawasaki disease, children normally are not given aspirin for minor fever or pain, because Reye syndrome * , a dangerous condition, has been linked to aspirin use in children.)
Much of the treatment for Kawasaki disease focuses on keeping the patient comfortable while the illness runs its course. After the disease clears up, children still need follow-up testing to make sure it has not caused heart disease. They may have additional echocardiograms or angiograms * to examine the heart for damage and sometimes a stress test * to check the heart's function.
* platelets (PLATE-lets) are tiny disk-shaped particles within the blood that play an important role in clotting (the body's way of thickening blood to stop bleeding).
* echocardiogram (eh-ko-KAR-dee-uh-gram) is a diagnostic test that uses sound waves to produce images of the heart's chambers and valves and blood flow through the heart.
* coronary arteries (KOR-uh-nair-e AR-tuh-reez) are the blood vessels that directly supply blood to the heart.
* blood clots are thickenings of the blood into a jelly-like substance that helps stop bleeding. Clotting of the blood within a blood vessel can lead to blockage of blood flow.
* gamma globulin (GAH-muh GLAH-byoo-lin) is a type of protein in the blood that contains the antibodies produced by the cells of the body's immune system that help defend the body against infection-causing germs, such as bacteria and viruses.
* Reye syndrome (RYE SIN-drome) is a rare condition that involves inflammation of the liver and brain, and sometimes appears after illnesses such as chicken pox or influenza. It has also been associated with taking aspirin during certain viral infections.
* angiogrom (AN-jee-o-gram) is a test in which X rays are taken as dye is injected into the body. showing the flow of blood through the heart and blood vessels.
* stress test measures the health of a person's heart while the heart is intentionally stressed by exercise or medication.
What Are the Possible Complications
of Kawasaki Disease?
Up to 25 percent of children with untreated Kawasaki disease may experience complications that involve the heart and coronary arteries. With treatment, that risk goes down to less than 5 percent. Babies younger than 1 year and children older than 9 years have the greatest risk of heart problems. By far the most serious complication of Kawasaki disease is coronary aneurysm. If an aneurysm clots or, more rarely, bursts in a blood vessel supplying the heart muscle, it can cause a heart attack or even death. Kawasaki disease can affect the heart in other ways as well, leading to myocarditis * or an irregular heartbeat.
Can Kawasaki Disease Be Prevented?
Because little is known about its cause, there are no proven ways to prevent Kawasaki disease.
* myocarditis (my-oh-kar-DYE-tis) is an inflammation of the muscular walls of the heart.
American Heart Association, National Center, 7272 Greenville Avenue,
Dallas, TX 75231. The American Heart Association provides information
about Kawasaki disease and related heart problems at its website.
U.S. National Library of Medicine, 8600 Rockville Pike, Bethesda, MD
20894. The National Library of Medicine's website provides
general information for the public on a variety of health topics,
including Kawasaki disease.