KAWASAKI DISEASE

Symptoms, Causes, Tests and diagnosis & Coping and Support

Definition

Kawasaki disease is a condition that causes inflammation in the walls of small- and medium-sized arteries throughout the body, including the coronary arteries. It mostly affects children from ages 2 to 5. Identified by a Japanese doctor, Tomisaku Kawasaki, in 1967, Kawasaki disease is also called mucocutaneous lymph node syndrome because it also affects lymph nodes, skin and the mucous membranes inside the mouth, nose and throat.

Kawasaki disease occurs more often in boys than girls, and most commonly in children of Japanese or Korean descent, although any child can get it. It can cause serious complications of the heart and the blood vessels that supply the heart. Some of the complications of Kawasaki disease may be life-threatening.

The condition is not preventable, but it's treatable in most cases. Most children recover from Kawasaki disease without serious problems.

Symptoms

The signs and symptoms of Kawasaki disease appear in phases.

First phase

The first phase begins with a fever, which often is higher than 104 F (40 C), spikes and remits, and lasts one to two weeks. Your doctor may suspect Kawasaki disease if the fever lasts for five or more days, and your child has developed four or more of these signs and symptoms:

• Extremely red eyes (conjunctivitis) without thick discharge
  
• A rash on the main part of the body (trunk) and in the genital area
  
• Red, dry, cracked lips and an extremely red, swollen tongue ("raspberry" tongue)
  
• Swollen, red skin on the palms of the hands and the soles of the feet
  
• Sore throat
  
• Swollen lymph nodes in the neck and perhaps elsewhere

Second phase

In the second phase of the disease, your child may develop:

• Peeling of the skin on the hands and feet, especially the tips of the fingers and toes, often in large sheets
  
• Joint pain
  
• Diarrhea
  
• Vomiting
  
• Abdominal pain

Third phase

In the third phase of the disease, signs and symptoms slowly go away unless complications develop.

Causes

No one knows what causes Kawasaki disease. A number of theories link the disease to bacteria, viruses, or environmental chemicals or pollutants, but none has been proved. Kawasaki disease doesn't appear to be hereditary.

When to seek medical advice

Most children with Kawasaki disease recover with no problems, with or without treatment. However, the disease can cause serious heart problems and joint damage. Treating Kawasaki disease within 10 days of its onset may greatly reduce the chances of lasting damage. It's important to contact your child's doctor if your child has signs or symptoms of this disease.

Tests and diagnosis

There's no specific test available to diagnose Kawasaki disease. Diagnosis largely is a process of ruling out diseases that cause similar signs and symptoms, including:

• Scarlet fever, which is caused by streptococcal bacteria and results in fever, rash, chills and sore throat
  
• Juvenile rheumatoid arthritis
  
• Stevens-Johnson syndrome, a disorder of the mucous membranes
  
• Toxic shock syndrome
  
• Measles
  
• Cytomegalovirus or Epstein-Barr virus infection

Your doctor may conduct a physical examination and have your child undergo other tests to aid in the diagnosis. These tests may include:

• Urine tests. These tests help rule out other diseases.
  
• Blood tests. Besides helping to rule out other diseases, blood tests look at white blood cell count, which is likely to be elevated, and the presence of anemia and inflammation, indications of Kawasaki disease.
  
• Electrocardiogram. This test uses electrodes attached to the skin to measure the electrical impulses of your child's heartbeat. Kawasaki disease can cause serious complications of the heart.
  
• Echocardiogram. This test uses ultrasound images to show how well the heart is functioning and provides indirect evidence on how the coronary arteries are functioning.

Complications

Kawasaki disease is the leading cause of acquired heart disease in children. About one in five children with the disease develops heart problems, but fewer than half of them will have permanent damage.

Heart complications include:

• Inflammation of the heart muscle (myocarditis)
  
• Enlargement of the heart (cardiomegaly)
  
• Abnormal heart rhythm (arrhythmia)
  
• Inflammation of blood vessels (vasculitis) , usually the coronary arteries, which supply blood to the heart

Any of these complications can cause your child's heart to malfunction. Inflammation of the coronary arteries can lead to aneurysms (weakening and bulging of the artery wall). Aneurysms increase the risk of blood clots forming and blocking the artery, which could lead to a heart attack or cause life-threatening internal bleeding.

For a small percentage of children who develop coronary artery problems, Kawasaki disease is fatal, even with treatment.

Treatments and drugs

Your doctor will want to begin initial treatment for Kawasaki disease as soon as possible after the appearance of signs and symptoms, preferably while your child still has a fever. The goals of initial treatment are to lower fever and inflammation and prevent heart damage.

To accomplish those goals, your child's doctor may recommend:

• Aspirin. High doses of aspirin can reduce the fever, rash, joint inflammation and pain and help prevent blood clots from forming.
  
• Gamma globulin. Infusion of gamma globulin (an immune protein) through a vein (intravenously) can lower the risk of coronary artery abnormalities.

Because of the risk of serious complications, initial treatment for Kawasaki disease usually is given in a hospital.

After the initial treatment

Once the fever subsides, your child may need to take low-dose aspirin for at least six to eight weeks, and longer if he or she develops a coronary artery aneurysm. Aspirin helps prevent clotting.

However, if your child develops flu or chickenpox during treatment, he or she will need to stop taking aspirin. Taking aspirin has been linked to Reye's syndrome, a rare but serious illness that can affect the blood, liver and brain of children and teenagers after a viral infection. (This is another reason to immunize your child on schedule against chickenpox.)

Without treatment, Kawasaki disease can last from two to 12 weeks. With treatment, your child may start to improve within 24 hours.

Monitoring heart problems

If your child has any indication of heart problems, your doctor may recommend follow-up tests to monitor heart health at regular intervals. If your child develops continuing heart abnormalities, your doctor may refer you to a doctor who specializes in treating heart disease in children (pediatric cardiologist) . In some cases, a child with a coronary artery aneurysm may require:

• Anticoagulant drugs. These medications, such as aspirin, warfarin and heparin, help prevent clots from forming.
  
• Coronary artery angioplasty. This procedure opens arteries that have narrowed to the point that they impede blood flow to the heart.
  
• Stent placement. This procedure involves implanting a device in the clogged artery to help prop it open and decrease the chance of re-blockage. Stent placement often accompanies angioplasty.
  
• Coronary artery bypass graft. This operation involves rerouting the blood around a diseased coronary artery by grafting a section of blood vessel from the leg, chest or arm to use as the alternate route.

Coping and support

Find out all you can about Kawasaki disease so that you can make informed choices with your child's health care team about treatment options. Keep in mind that most children with Kawasaki disease recover completely within the first six months after they begin treatment.