Kawasaki Disease

Diagnosis

No laboratory test can diagnose Kawasaki disease with 100 percent certainty. Instead, a set of criteria described by the Centers for Disease Control is used. Occasionally the diagnosis of Kawasaki disease is uncertain, and a spinal tap may be necessary since it can show mild inflammation of the spinal fluid (aseptic meningitis). Some children develop coronary artery changes without meeting all the diagnostic criteria, referred to as "atypical Kawasaki disease." This is more common in infants, who often have more subtle or incomplete symptoms.

The symptoms of Kawasaki disease can go away without treatment. However it may take 6-8 weeks for the symptoms to resolve and the child's laboratory results to return to normal. The effects on the coronary arteries can last a lifetime. The illness can be divided into three phases: acute, subacute, and convalescent.

The Acute Phase

The acute phase starts with a fever that lasts for at least five days (the average is 11 days without treatment). Symptoms appear in the first week, but often one symptom appears as another disappears, making the diagnosis challenging, especially in children who see different physicians during the early days of their illness. An ultrasound of the heart (echocardiography or ECHO) is done upon diagnosis to get baseline measurements of the coronary arteries. Some children may have mild or moderately decreased heart output due to poor contraction of inflamed heart muscle, and some may have a small amount of fluid around the heart (pericardial effusion). Very rarely, cardiac rhythm (electrical) disturbances may occur.

The Subacute Phase

The subacute phase begins when the fever stops. During this stage one of the most characteristic symptoms of the disease may be seen — peeling of the skin of the palms and soles beginning under the fingertips and toes. The child's joints may also be inflamed, especially larger weight-bearing joints.

The Convalescent Phase

In this phase, the child continues to recover and laboratory tests results return to normal. Although the child is usually feeling better, coronary aneurysms may continue to enlarge, becoming largest four to six weeks from the first day of fever.