What Is Kawasaki Disease?
Kawasaki disease is a rare but serious illness that causes heart problems in children. It is a form of a condition called vasculitis (inflammation of the blood vessels). The blood vessels include arteries, veins, and capillaries.
Sometimes, the disease affects the coronary arteries that supply oxygenated blood to the heart. If the disease affects the coronary arteries, it can lead to severe heart problems including myocarditis (inflammation of the heart muscle), dysrhythmia (abnormal heart rhythm), and aneurysm (weakening and bulging of the artery wall).
The disease can also affect the lymph nodes, the skin, and the mucous membranes found inside the nose, throat, and mouth.
Kawasaki disease was described by and named after Japanese pediatrician Tomisaku Kawasaki in 1967. It is also called mucocutaneous lymph node syndrome or Kawasaki syndrome.
Although Kawasaki disease was first described in Japan, the disease is found all over the world. It is more common in boys than in girls. The Kawasaki Disease Foundation (KDF) estimates that Kawasaki disease affects more than 4,200 children in the United States each year (KDF). According to a 1999 review published in American Family Physician, it is one of the primary causes of acquired heart disease in children in the United States and other developed countries (Taubert & Shulman, 1999).
Kawasaki disease can be alarming, but children will usually recover in a few weeks without developing serious heart problems if they are treated early. Relapses are uncommon. However, if the disease is not treated, it may lead to problems with the arteries of the heart and death due to a heart attack.
What Causes Kawasaki Disease?
The exact cause of Kawasaki disease is still unknown. Some studies suggest that it may be caused by the immune system’s reaction to an infectious agent, such as a virus. The condition itself is not contagious.
Who Is at Risk for Kawasaki Disease?
Kawasaki disease affects all ethnicities but is most common in children of Asian descent. Most patients are children under the age of 5.
What Are the Symptoms of Kawasaki Disease?
Kawasaki disease occurs in stages.
Early symptoms may include:
- high fever (often greater than 102 degrees and even as high as 104 degrees Fahrenheit) that persists for five or more days
- bloodshot eyes (also known as “conjunctivitis without discharge”)
- swollen, bright red tongue (referred to as a strawberry tongue)
- swollen lymph nodes
- swollen hands and feet
- red palms and soles of the feet
Later symptoms may include:
- peeling skin on the hands and feet (the skin may come off in sheets)
- pain in the joints
How Is Kawasaki Disease Diagnosed?
There are no specific tests for Kawasaki disease. A pediatrician will take into account the child’s symptoms and rule out illnesses with similar symptoms, such as:
- scarlet fever, a bacterial infection that causes fever, chills, and sore throat
- juvenile rheumatoid arthritis, a chronic disease that causes joint pain and inflammation
- Rocky Mountain spotted fever, a tick-borne illness
Kawasaki disease should be considered a possibility in any infant or child who has a fever lasting more than five days or the other classic symptoms of the disease.
A pediatrician might order additional tests to check how the disease has affected the heart. These may include:
An echocardiograph is a painless procedure that uses sound waves to create pictures of the heart and its arteries. This test may need to be repeated to show how Kawasaki disease has affected the heart over time.
Blood tests may be ordered to rule out other illnesses, to look at white blood cell count (which is likely to be elevated in Kawasaki disease), and to check for anemia (too few red blood cells) and inflammation (indicated by increases in C-reactive protein and erythrocyte sedimentation rate), which are indications of Kawasaki disease.
A chest X-ray creates black and white images of the heart and lungs. A doctor may order this test to look for signs of heart failure and inflammation.
An electrocardiogram, or ECG, records the electrical activity of the heart. Irregularities in the ECG may indicate that the heart has been affected by Kawasaki.
What Are the Possible Complications of Kawasaki Disease?
Kawasaki disease leads to serious heart problems in 20 to 25 percent of untreated children according to a review published in American Family Physician (Taubert, et al., 1999).
Inflammation of the arteries may lead to a condition called an aneurysm. An aneurysm is abnormal swelling of a blood vessel, which can lead to blood vessel rupture. Rarely, the vessel will rupture and cause a heart attack, which can be fatal.
How Is Kawasaki Disease Treated?
Children showing symptoms of Kawasaki should be admitted to the hospital, and treatment should begin immediately to prevent damage to the arteries and heart.
The usual treatment includes high doses of aspirin to decrease inflammation and reduce pain, and a high dose of gamma globulin (an immune protein) given intravenously. Usually, a child will improve within a day.
The child may need to continue to take lower doses of aspirin for six to eight weeks after the fever goes away to prevent the formation of blood clots.
At present, there is no known way to prevent Kawasaki disease.
What Can Be Expected in the Long Term?
Early diagnosis and treatment typically results in a full recovery. Most children get better within a few weeks. About one percent of patients in the United States will die from complications (Sheinfeld, et al.).
Children who have had Kawasaki disease should receive an echocardiogram every one or two years to screen for heart problems.