Kawasaki Disease

Kawasaki Disease (KD) is also termed “muco-cutaneous lymph node syndrome.” The cause of Kawasaki Disease has not been identified. Kawasaki Disease is considered a self-limited disease — after a period of time and even without medical consultation, the symptoms often resolve and the patient recovers. Without medical consultation, however, potential serious complications may develop and may not be recognized.

Kawasaki Disease most often affects children less than 4 years old with the majority being less than 2 years; although cases in older children have also been reported. The incidence of patients who have a sibling who has had Kawasaki Disease  is 1 percent.

Due to the findings of high fever and enlarged lymph glands, Kawasaki Disease is thought to be an inflammatory process. Because the inflammation often involves the blood vessels of the body, Kawasaki Disease is felt to be a vasculitis (an inflammation of a blood vessel). The cause of this inflammatory response is not known.

There are no specific tests to diagnose Kawasaki Disease. A prolonged fever is often the first symptom that alerts the physician to consider Kawasaki Disease. Features that make the diagnosis include:

  • Prolonged high fever (lasting longer than 5 days)
  • A non-specific rash that often involves the groin area
  • Painful joints
  • Red eyes, or conjunctivitis without discharge
  • Very red lips and tongue
  • Enlarged neck lymph gland(s)
  • Puffy” hands and feet occasionally followed by peeling of their superficial skin
  • Irritability in younger patients. In some children, enlargement of the gall bladder can cause abdominal pain and vomiting.

These symptoms are nonspecific and mimic other diseases such as Scarlet Fever.

To find supporting data or to eliminate other conditions that resemble Kawasaki Disease, a physician might request blood tests. These may include tests to assess:

  • For recent Streptococcal or viral infection
  • The body’s inflammatory / immune response, e.g. a complete blood count (CBC) and an ESR or “sedimentation rate”.

Sometimes a sample of urine is obtained to test for increased white cells, another marker of inflammation. These tests are helpful; however, the only way to make the diagnosis of Kawasaki Disease is by meeting the clinical criteria listed above.

Kawasaki Disease can affect the heart by causing the following complications:

  • Coronary artery aneurysms
  • Leakage of valves (often mitral valve regurgitation)
  • Accumulation of fluid around the heart (pericardial effusion)

Coronary artery aneurysms are the most important complication of Kawasaki Disease. An aneurysm is severe dilation of the wall of a blood vessel.

In Kawasaki Disease, this dilation involves the coronary arteries (the blood vessels that supply oxygen and nutrients to the heart itself). In patients with Kawasaki Disease that is not treated, the risk of developing these coronary changes is about 20 percent.

Patients diagnosed with Kawasaki Disease undergo an echocardiogram to assess the coronary arteries. The echocardiogram is repeated 6-8 weeks after the onset of Kawasaki Disease because the development of aneurysms may be delayed.  In general, if coronary artery changes have not occurred by 6 months after the onset of the illness, the risk of developing the changes is very low.

Depending on the size of the aneurysm, the coronary changes can resolve, remain unchanged, or progress. Patients with large aneurysms are at risk for developing coronary artery stenoses or narrowing as the aneurysms heal.  It has been reported that in 50 percent of the patients with small coronary aneurysms, the changes resolve during the first year after the illness. Unfortunately, physicians cannot predict which course a patient will take.

Since we do not know what causes Kawasaki Disease, there is no specific therapy for it. Based upon the thought that Kawasaki Disease is due to an inflammatory process, the therapy has centered on using anti-inflammatory medications, and this approach has helped decrease the complications of Kawasaki Disease. Currently, high dose aspirin and an intravenous infusion of gamma globulin (body’s natural product formed to counter an infectious agent) are used as a treatment.

The medical literature indicates that an infusion of gamma globulin (IVIG) can decrease, but NOT eliminate, the risk of developing coronary aneurysms. The infusion is most effective if given within the first 10 days of the illness. The risk of developing coronary changes decreases to less than five percent when treated in the first 10 days.

If your child meets the criteria for the diagnosis of Kawasaki Disease, a cardiologist will be consulted. The cardiologist will obtain an electrocardiogram and an echocardiogram.

Even if these studies are normal, your child should receive IVIG and high dose aspirin because these medications are used in an attempt to prevent the complications of Kawasaki Disease by minimizing the degree of inflammation. Usually your child will be admitted to the hospital for at least 1-2 days.

After discharge, they will continue to take aspirin until the signs of inflammation have resolved (usually 2 weeks or more).
Parents are often concerned about using aspirin in children due to the concern over the association of aspirin use and Reye syndrome. Reye syndrome is an inflammatory process that occurs in the brain and has been associated with patients using aspirin chronically and who also have chicken pox or influenza.

If your child is on aspirin and he or she has been exposed to or has chicken pox, you should contact your physician immediately for further advice.

Some physicians will recommend that if your child is taking aspirin chronically for any reason, he or she should have a flu shot to avoid influenza infection.
Outpatient echocardiograms are performed 6-8 weeks, 6 months, and 1 year after the onset of illness. If by 6 months there is no evidence of cardiac involvement, your child’s cardiac risks are extremely low. If your child does have cardiac involvement, they will need regular cardiology visits.

If your child has coronary artery changes, they will require continued cardiology follow-up. Due to the vessel wall irregularity, a coronary artery aneurysm can become a site of blood clot formation. If a large enough blood clot forms, it can cause obstruction to blood flow, and the heart tissue becomes deprived of needed nutrients.

Depending upon the size and number of the coronary aneurysms, your child may need to be on medication to prevent blood clotting. If the aneurysms are small and few, the medication is aspirin taken once a day. If the aneurysms are large (termed “giant aneurysms”), a “blood thinner” such as Coumadin (warfarin) is used.

Children with giant coronary aneurysms will need periodic cardiac catheterization to assess the size of the vessels. Periodic stress/exercise tests are used to assess the heart’s ability to obtain adequate nutrients during exertion.

Children with larger coronary artery aneurysms or abnormal stress / exercise tests may require restriction from certain physical activities.
If after one year from the diagnosis of Kawasaki Disease there is no heart involvement, the patient is often discharged from further cardiology evaluations. The majority of the patients fall in this category, and they have an excellent prognosis.

Patients that have coronary aneurysms will require periodic cardiology evaluations. The frequency of these visits varies depending on the extent of coronary changes. Often these visits are scheduled once every six to twelve months. With appropriate medical care, these patients also often have an excellent prognosis.

Victoria & Tasmania