Kawasaki Disease (KD)

Kawasaki disease is a childhood illness that causes blood vessels to become inflamed (vasculitis) and swell. Kawasaki disease is a serious illness because it can cause life-threatening inflammation of blood vessels that supply oxygen and nutrients to the heart (the coronary arteries). This complication can usually be prevented by early diagnosis and treatment.

Kawasaki disease is most common in children younger than 5 years old; however, older children can be affected as well. KD occurs more often among boys and is more commonly seen in the winter and spring months. The exact cause of KD is unknown, but it is suspected that it may be triggered by an infection. It may also occur in children who have a genetic predisposition to the disease. Kawasaki disease is not contagious.

The most common symptoms of Kawasaki disease are:

• Fever (100.40 F or higher) that lasts for five or more days
• Rash
• Red bloodshot eyes without drainage
• Bright red, swollen, cracked lips and tongue
• Red, swollen hands and feet that may peel
• Swollen lymph nodes on one side of the neck (will feel like a lump on the side of the neck)

Children with Kawasaki disease may also have painful or swollen joints, extreme fussiness especially in younger children, and swelling of the gallbladder that can cause belly pain and vomiting.

There is no specific test to diagnose Kawasaki disease. Rather, doctors diagnose Kawasaki disease based on a child’s symptoms and physical exam. A prolonged fever (i.e., more than five days) is often the first symptom that alerts a doctor to consider Kawasaki disease.

Lab tests may help with diagnosis. This may include:

• Blood and urine tests
• ECG (electrocardiogram): looks at the electrical system of heart
• Echocardiogram (ultrasound of the heart) to look at the size of the blood vessels around the heart and how the heart is functioning.

These laboratory tests are helpful; however, the only way to make the diagnosis of Kawasaki disease is by meeting the clinical criteria for most of the signs and symptoms listed above, and making sure the child’s illness is not caused by something else, like an infection.

If a child is diagnosed with Kawasaki disease, they are also seen by a cardiologist. They will have an electrocardiogram (to assess the electrical system of the heart) and an echocardiogram (ultrasound of the heart). Even if these studies are normal, the child will receive treatment based on clinical symptoms and lab work.

There are two main treatments for Kawasaki Disease:

• Aspirin therapy
  Aspirin is given every 6 hours initially. Then the dose decreases to once a day. A child may have to continue taking aspirin for an extended period.
• Intravenous immunoglobulin
  Intravenous immunoglobulin (IVIG) is a medicine that reduces the swelling in the blood vessels. This is given through your child’s IV.

Parents are sometimes concerned about using aspirin in children due to the concern over the link between aspirin use and Reye syndrome. Reye syndrome is an inflammatory process that affects the brain and liver and has occurred in patients taking aspirin who are infected with chicken pox or influenza. Most doctors suggest that if your child is taking aspirin for a long period for any reason, they should have a flu shot to avoid influenza infection. If your child is on aspirin and they have been exposed to or have chicken pox, you should contact your doctor immediately for advice.

What is the long-term outcome of KD?

Long-term outcomes depend on how much the coronary arteries were affected by the disease. Follow-up care is very important because, often, damage to the coronary arteries does not show up until several weeks later. Fortunately, with appropriate treatment, most children do not have any long-term sequelae from KD.

Children that do have coronary artery involvement will need regular cardiology evaluations. The frequency of these visits can depend on the extent of coronary changes. With the right medical care, these patients also generally have a good outcome.

Long-term outcomes depend on how much the coronary arteries were affected by the disease. Follow-up care is very important because, often, damage to the coronary arteries does not show up until several weeks later. Fortunately, with appropriate treatment, most children do not have any long-term sequelae from KD.

Children that do have coronary artery involvement will need regular cardiology evaluations. The frequency of these visits can depend on the extent of coronary changes. With the right medical care, these patients also generally have a good outcome.

Since there is no specific test to diagnose Kawasaki, rheumatologists often help decide if a child’s illness is caused by Kawasaki disease or another condition.

Rheumatologists may also help to treat children with Kawasaki disease who do not respond to the usual treatments discussed above. In these children, doctors may use other medicines that rheumatologists commonly used to treat other diseases such as arthritis.