KAWASAKI DISEASE

What is Kawasaki's disease?

Kawasaki's disease is an uncommon illness in children that is characterized by high fever of at least five days' duration together with at least four of the following five findings:

1. Inflammation with reddening of the whites of the eyes (conjunctivitis) without pus
2. Redness or swelling of the hands or feet, or generalized skin peeling
3. Rash
4. Lymph node swelling in the neck
5. Cracking inflamed lips or throat, or red "strawberry" tongue

The above criteria are used to make a diagnosis of Kawasaki's disease. The terminology "incomplete Kawasaki's disease" is sometimes used for patients with only some features of classical Kawasaki's disease.

What is mucocutaneous lymph node syndrome?

Mucocutaneous lymph node syndrome is the original name for Kawasaki's disease. The original name was quite descriptive because the disease is characterized by the typical changes in the mucous membranes that line the lips and mouth and by the enlarged and tender lymph nodes.

What are the usual symptoms and signs of Kawasaki's disease?

The usual symptoms and signs of Kawasaki's disease include

• fever,
• reddening of the eyes,
• cracked and inflamed lips and mucous membranes of the mouth with an inflamed "strawberry" tongue,
• ulcerative gum disease (gingivitis),
• swollen lymph nodes in the neck (cervical lymphadenopathy),
• and a rash that is raised and bright red.

The rash appears in a glove-and-sock fashion over the skin of the hands and feet. The rash becomes hard, swollen (edematous), and then peels off.

What are the less common findings?

Most of the common symptoms described above will resolve without complications, even if untreated. Less common findings include inflammation of the lining of the heart (pericarditis), joints (arthritis), or covering of the brain and spinal cord (meningitis), and the other heart complications listed below in the section on serious complications. The outlook (prognosis) for an individual affected is primarily determined by the seriousness of any heart complications.

What is the difference between Kawasaki's disease and Kawasaki's syndrome?

They are the same. Kawasaki's disease is also referred to as Kawasaki's syndrome. It was first described in the late 1960s in Japan by the pediatrician Tomisaku Kawasaki.

What causes Kawasaki's disease?

The cause is not known. Microorganisms and toxins have been suspected, but none has been identified to date. Kawasaki's disease is not felt to be a contagious illness. Genetic factors and the immune system seem to play roles in the disease, which is characterized by immune activation.

Who develops Kawasaki's disease?

Kawasaki disease typically affects children under 5 years of age. Only rarely does it affect children over 8 years of age, in which case it is sometimes referred to as atypical Kawasaki's disease.

How can Kawasaki's disease cause serious complications?

Children with Kawasaki's disease can develop inflammation of the arteries of various parts of the body. This inflammation of the arteries is called vasculitis. Arteries that can be affected include the arteries that supply blood to the heart muscle (the coronary arteries). Vasculitis can cause weakening of the blood vessels and lead to areas of vessel widening (aneurysms). Coronary aneurysms have been reported in up to 25% of those with Kawasaki's disease.

Because of the potential for heart injury and coronary aneurysms, special tests are performed to examine the heart. Children are typically evaluated with an electrocardiogram (EKG) and an ultrasound test of the heart (echocardiogram). Other arteries that can become inflamed include the arteries of the lungs, neck, and abdomen. These effects can lead to breathing problems, headaches, and pain in the belly, respectively.

What is the treatment for Kawasaki's disease?

Kawasaki's disease is treated with high doses of aspirin (salicylic acid) to reduce inflammation and to mildly thin the blood to prevent blood clot formation. Also used in treatment is gamma globulin administered through the vein (intravenous immunoglobulin or IVIG), together with fluids. This treatment has been shown to decrease the chance of developing aneurysms in the coronary arteries. Sometimes cortisone medications are given. Persisting joint pains are treated with anti-inflammatory drugs, such as ibuprofen (Advil) or naproxen (Aleve).

Plasma exchange (plasmapheresis) has been reported as effective in patients who were not responding to aspirin and gammaglobulin. Plasmapheresis is a procedure whereby the patient's plasma is removed from the blood and replaced with protein-containing fluids. By taking out portions of the patient's plasma, the procedure also removes antibodies and proteins that are felt to be part of the immune reaction that is causing the inflammation of the disease. Kawasaki's disease that is not responding to the traditional aspirin and gammaglobulin treatments can be deadly. Medications that block the effects of TNF (tumor necrosis factor), one of the messenger molecules in the inflammatory response, are being studied for use in these situations. Examples of TNF-blocking drugs are infliximab (Remicade) and etanercept (Enbrel). Further research is needed to design treatment programs for those who are failing conventional treatments. Pentoxifylline (Trental) is also being studied as a possible treatment for Kawasaki's disease.

What is the outlook (prognosis) for children with Kawasaki disease?

Kawasaki's disease generally resolves on its own after four to eight weeks.

However, the outcome is not so favorable in every case. Rarely, Kawasaki's disease can cause death from blood clots forming in abnormal areas of widening (aneurysms) of the heart arteries (coronary arteries). Those children with larger aneurysms have a worse prognosis because of this risk.

Researchers are searching for methods of detecting which children are at risk for the development of aneurysms of the coronary arteries. Further research is under way to investigate a variety of criteria for atypical variants of Kawasaki's disease that do not have classical presentations.

Kawasaki Disease At A Glance

• Kawasaki's disease is a syndrome of unknown cause that mainly strikes young children.
• Signs of the disease include fever and redness of the eyes, hands, feet, mouth, and tongue.
• The disease can be treated with high doses of aspirin (salicylic acid) and gammaglobulin.
• Kawasaki's disease usually resolves on its own within a month or two.
• Some children with Kawasaki's disease suffer damage to the coronary arteries.