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Kawasaki Disease

Though it is rare, Kawasaki disease is one of the leading causes of acquired heart disease in children. Kawasaki disease is a very serious disease that causes inflammation in the blood vessels throughout the body, including the coronary arteries. The good news is, recognizing and treating the disease early can greatly reduce the risk of long-term effects on your child's heart.

In the United States, after congenital heart defects, Kawasaki disease is the leading cause of heart disease in children. Most of these patients are younger than age 5. The disease occurs more often in boys than in girls.

What is Kawasaki disease?

Kawasaki disease is a poorly understood illness; the cause has not been determined. It may be an autoimmune disorder. The disorder affects the mucus membranes, lymph nodes, walls of the blood vessels and the heart.

The immediate effects of Kawasaki disease are rarely serious; however, long-term heart complications result in some cases and can be seen as early as two weeks after onset of the disease.

Children who receive treatment within the first 10 days of illness have a less than four percent risk of developing damage to the heart. Children who go untreated have as much as a 20 percent chance of developing damage and even aneurysms in the coronary arteries.

Owing to limited knowledge, the disease often goes undetected in many children. Instead, damage to the heart is allowed to perpetuate and harm the child.

If your child has Kawasaki disease, the expert pediatric team at Cook Children's Heart Center will evaluate the stage and extent of the disease and, where possible, prevent damage to the cardiovascular system. Should there be damage, our team of pediatric heart specialists works closely with other specialty teams across the Cook Children's system, including those in infectious disease and rheumatology, among others.

Kawasaki disease can also cause problems with the heart, including:

  • Inflammation of a child's blood vessels (vasculitis), especially their coronary arteries. The coronary arteries supply the heart with blood and inflammation can lead to enlargement of these arteries. This can cause a scar to form, narrowing the arteries. In the worst case, a clot can form in the arteries and block blood flow to the heart
  • Swelling of their heart muscle (myocarditis) or the sac around their heart (pericarditis)
  • Arrhythmia

The most serious problems from Kawasaki disease are the effects it may have on the heart and its arteries. In rare cases Kawasaki disease can result in heart failure, heart attack and even death. This is why treating Kawasaki disease is so critical. According to the American Heart Association, Kawasaki disease affects the hearts of one in five children with the disease.

What causes Kawasaki disease?

The cause of Kawasaki disease is unknown, although a virus-like agent is suspected. However, it is not contagious. Kawasaki disease occurs in 19 out of every 100,000 kids in the United States. It is most common among children of Japanese and Korean descent, but can affect all ethnic groups.

While the cause is unknown, the damage caused by this disease is well known. Kawasaki disease causes inflammation in the blood vessels. This means it can travel all through the body and affect the skin, eyes, mouth, breathing passages and lymph nodes. This disease can also cause serious damage to the heart, inflaming the coronary arteries and causing myocarditis.

Who gets Kawasaki disease?

Each year, more than 4,200 children in the U.S. are diagnosed with Kawasaki disease. Nearly 80 percent of all cases of Kawasaki disease are children under the age of five. More cases are diagnosed in winter and early spring. The following may be considered to be possible risk factors for Kawasaki disease:

  • Age – children aged between two to five years are at greater risk of developing the disease compared with other age groups. Older children and teenagers may also develop Kawasaki disease, but this is rare.
  • Gender – Boys are more likely to develop the disease than girls
  • Race – Although children of Asian and Pacific Island descent are more often diagnosed with Kawasaki disease, it affects all children of all racial and ethnic groups.
  • Children with Asian ancestry, particularly Chinese and Japanese, are more likely to develop the disease than kids of other ethnic backgrounds. But there is no correlation to socio-economics.

Signs and symptoms

Kawasaki disease usually has telltale symptoms and signs that appear in phases.

The first phase, which can last for up to two weeks, often begins with a high and persistent fever greater than 102 degrees Fahrenheit, sometimes as high as 104 degrees Fahrenheit. A persistent fever lasting at least five days is considered a classic sign. The fever may last for up to two weeks and does not usually go away with normal doses of acetaminophen (Tylenol) or ibuprofen. Other symptoms in this phase may include:

  • Extremely bloodshot or red eyes (without pus or drainage)
  • Bright red, chapped or cracked lips
  • Red mucous membranes in the mouth
  • Strawberry tongue, white coating on the tongue or prominent red bumps on the back of the tongue
  • Red palms of the hands and the soles of the feet
  • Swollen hands and feet
  • Skin rashes on the middle of the body (these are not blister-like but are usually red)
  • Peeling skin in the genital area, hands and feet (especially around the nails, palms and soles)
  • Swollen lymph nodes (frequently only one lymph node is swollen), particularly in the neck area
  • Joint pain and swelling, frequently on both sides of the body

Additional symptoms may include:

  • Irritability
  • Diarrhea, vomiting and abdominal pain
  • Cough and runny nose
  • Conjunctivitis
  • Gingivitis

During the second phase, which usually begins within two weeks of when the fever started, the skin on the hands and feet may begin to peel in large pieces. The child also may experience joint pain, diarrhea, vomiting or abdominal pain. If your child shows any of these symptoms, call your doctor.

Doctors can manage the symptoms of Kawasaki disease if they catch it early. Symptoms often disappear within just 2 days of the start of treatment. If Kawasaki disease is treated within 10 days of the onset of symptoms, heart problems usually do not develop.

Cases that go untreated can lead to more serious complications, such as vasculitis, an inflammation of the blood vessels. This can be particularly dangerous because it can affect the coronary arteries, which supply blood to the heart.

In addition to the coronary arteries, the heart muscle, lining, valves, and the outer membrane that surrounds the heart can become inflamed. Arrhythmias (changes in the normal pattern of the heartbeat) or abnormal functioning of some heart valves also can occur.

Testing and diagnosis

Because symptoms often resemble those of other childhood diseases and there's no definitive test available, the diagnosis of Kawasaki disease cannot be made by a single laboratory test or combination of tests. Physicians make the diagnosis after carefully examining a child, observing signs and symptoms and eliminating the possibility of other, similar diseases. Blood tests are used to detect mild anemia, an elevated white blood cell count and an elevated sedimentation rate, indicating inflammation. A sharp increase in the number of platelets, a major clotting element in blood, also may be found. Urine tests may reveal the presence of protein (albumin) and white blood cells. An echocardiogram (or echo) is used to look for possible damage to the heart or to the coronary arteries that supply blood to the heart muscle. Other blood tests or diagnostic studies may be requested by the physician.

Depending on the symptoms your child has, the following tests may be performed:

  • Chest x-ray
  • Complete blood count
  • C-reactive protein (CRP)
  • Echocardiography
  • Electrocardiogram
  • ESR
  • Serum albumin
  • Serum transaminase
  • Urinalysis – may show pus in the urine or protein in the urine
  • Procedures such as ECG and echocardiography may reveal signs of myocarditis, pericarditis, arthritis, aseptic meningitis and inflammation of the coronary arteries

Diagnosis

No single test can detect Kawasaki disease, so doctors usually diagnose it by evaluating the symptoms and ruling out other conditions.

Most kids diagnosed with Kawasaki disease will have a fever lasting five or more days and at least four of these symptoms:

  • Redness in both eyes
  • Red, peeling lips or strawberry tongue
  • Swelling, discoloration or peeling of the fingers and toes
  • Rash in the trunk or genital area
  • Large swollen lymph nodes in the neck
  • Red, swollen palms of hands and soles of feet

If Kawasaki disease is suspected, the doctor may order tests to monitor heart function (such as an echocardiogram) and might take blood and urine samples to rule out other conditions, such as scarlet fever, measles, Rocky Mountain spotted fever, juvenile rheumatoid arthritis or an allergic drug reaction.

Treatment

Treatment should begin as soon as possible, ideally within 10 days of when the fever begins. Usually, a child is treated with intravenous doses of gamma globulin (purified antibodies), an ingredient of blood that helps the body fight infection. The child also might be given a high dose of aspirin to reduce the risk of heart problems.

Children with Kawasaki disease are admitted to the hospital. Treatment must be started as soon as the diagnosis is made to prevent damage to the coronary arteries and heart.

Intravenous gamma globulin is the standard treatment. It is given in high doses. The child's condition usually greatly improves within 24 hours of treatment with IV gamma globulin. High-dose aspirin is often given along with IV gamma globulin. Even when they're treated with aspirin and IV gamma globulin, up to 25% of children may still develop problems in their coronary arteries. Some research has suggested that adding steroids to the usual treatment routine may improve a child's outcome, but more research is needed.

The possibility of heart and coronary artery involvement makes Kawasaki disease unpredictable, but these problems usually are not serious and disappear with time. However, on occasion aneurysm of coronary or other arteries of the body can occur, and some may require medical or surgical treatment. Very rarely, complications may include heart attacks, which can be fatal.

Kawasaki disease is frequently treated in the hospital, with a stay from a few days to a few weeks. Some children may receive care at home without hospitalization.

Even though the cause of Kawasaki disease is unknown, specific medications are known to be beneficial. Aspirin is used to reduce fever, rash, joint inflammation, and pain, and to prevent formation of blood clots. Recent studies from Japan, the United States, and other countries indicate that another medication, intravenous gamma globulin, decreases the risk of developing heart disease when given early in the illness. A major goal of treatment both in the hospital and at home is to make a child as comfortable as possible while the illness runs its course.

If tests reveal an aneurysm or other heart or blood vessel abnormality, repeated echocardiograms or other tests may be necessary for several years following recovery from Kawasaki disease. Almost all children return to completely normal activity after the acute phase of the illness. Even if there is no evidence of a heart abnormality when your child recovers from the acute phase of Kawasaki disease, it is important to bring your child in for a follow-up visit with your doctor to be sure that there aren't heart problems that did not show up right away.

Prevention

There is no known prevention for Kawasaki disease. Approximately one child in a hundred may develop the disease a second time. Parents should know that nothing they could have done would have prevented the disease.

We're here to help.

If your child has been diagnosed, you probably have lots of questions. We can help. If you would like to schedule an appointment, refer a patient or speak to our staff, please call our offices at 682-885-2140.