This disease was first described in 1967 by a Japanese pediatrician named Tomisaku Kawasaki. He described a number of children with fever, rash, conjunctivitis (inflammation of the eye), a red throat, red oral mucosa, swelling of the hands and feet, and enlarged lymph nodes in the neck. This condition was initially called mucocutaneous (muco = mucous membrane and cutaneous = skin) lymph node syndrome. A few years later, cardiac complications, such as coronary aneurysms (severe dilation of blood vessels), were reported in some of these children.WHAT DOES THE DISEASE ENtail?Kawasaki disease is an acute systemic vasculitis. This means that the blood vessel wall is inflamed, which can lead to aneurysms. It primarily affects the coronary arteries (the blood vessels that supply the heart). Not all children with this disease develop aneurysms. The vast majority do exhibit the aforementioned acute symptoms, without cardiac complications.HOW COMMON IS THE DISEASE?Although Kawasaki disease is rare, it is one of the most common vasculitides in childhood, along with Henoch-Schönlein. It occurs almost exclusively in young children. Approximately 80 out of 100 patients are under the age of 5. Slightly more than half of the cases involve boys. Kawasaki disease is diagnosed year-round, although some seasonal variation does exist. The disease occurs more frequently in late winter and early spring. The disease is more common in Japanese children, but cases have been reported worldwide
.WHAT ARE THE CAUSES OF THE DISEASE?Although an infection could be a possible cause of Kawasaki disease, the exact cause remains unknown. Hypersensitivity, an abnormal immune response, or an infection (viral or bacterial) can trigger an inflammatory process. This can lead to inflammation and damage to the blood vessels. Genetic susceptibility may play a role.IS IT HEREDITARY? WHY DOES MY CHILD HAVE THE DISEASE? CAN IT BE PREVENT? IS IT CONTAGIOUS?Kawasaki disease is not hereditary, although there appears to be a genetic susceptibility. It is very rare for the disease to affect more than one family member. Kawasaki disease is not contagious and cannot be prevented. It is possible, but very rare, for a child to develop the disease twice.WHAT ARE THE MAIN SYMPTOMS?The illness begins with a fever (ECI) lasting at least 5 days. The child is often irritable. The fever may be accompanied by conjunctival inflammation (redness of the eye) without pus or discharge. This redness may accompany the fever, but can also appear later.
Various types of rash may occur with Kawasaki disease, resembling measles, scarlet fever, papules, urticaria (hives), etc. The rash usually affects the trunk and extremities, and sometimes the diaper area.
Various oral abnormalities may be observed, including red, cracked lips, a red tongue (commonly called strawberry tongue), and a red throat.
The hands and feet may also be affected, with swelling and redness of the palms and soles. These symptoms are usually followed (around the second or third week) by characteristic peeling of the fingertips and toes.
More than half of patients have enlarged lymph nodes in the neck, usually one solitary lymph node measuring at least 1.5 cm.
Sometimes there are additional symptoms, such as joint pain and/or swollen joints, abdominal pain, diarrhea, irritability, headaches, etc.
Cardiac involvement is the most serious manifestation of Kawasaki disease due to the risk of long-term complications. Heart murmurs, arrhythmias, and abnormalities on cardiac ultrasound may be found. All different parts of the heart can become mildly inflamed. This means that pericarditis (inflammation of the sac surrounding the heart), myocarditis (inflammation of the heart muscle), and inflammation of the valves can occur. However, the most common symptom of Kawasaki disease is the development of coronary aneurysms.IS THE DISEASE THE SAME IN EVERY CHILD?The severity of the disease varies from child to child. Not every patient has all the clinical manifestations, and many patients will not show any cardiac involvement. Aneurysms occur in only 2 out of 100 children treated for Kawasaki disease.
Some very young children (before the age of 1) often exhibit incomplete forms of the disease, meaning they do not have all the characteristic clinical manifestations. This makes diagnosis difficult. Some of these young children may develop aneurysms.
Is the disease different in children than in adults?
Kawasaki disease is a childhood disease. Similar forms of this vasculitis can occur in adulthood, but with different clinical symptoms.HOW IS THE DIAGNOSIS MADE?A definitive diagnosis can be made if there is an unexplained fever lasting at least five days. Four of the following symptoms must be present:
- bilateral conjunctivitis (inflammation of the eye).
- enlarged lymph nodes.
- skin rash.
- mouth and tongue involvement.
- changes in the extremities.
Other causes that could cause such symptoms must be ruled out.
A definitive diagnosis is not possible; incomplete forms of this disease should also be considered if such symptoms are present.WHAT IS THE IMPORTANCE OF DIAGNOSTICS?Blood test findings are not specific for Kawasaki disease but indicate the severity of the inflammation. Signs of inflammation include:
- Elevated erythrocyte sedimentation rate (usually higher than in similar diseases).
- Leukocytosis (increased white blood cell count).
- Anemia.
Platelet counts (cells involved in clotting) are usually normal in the first week of the illness, but increase in the second week, after which they reach high levels. Patients should have frequent blood tests until the blood values have normalized.
An electrocardiogram (ECG) and echocardiogram should be performed at the onset of the illness. The echocardiogram can detect aneurysms by determining the shape and size of the coronary vessels. If a child is diagnosed with coronary vessel abnormalities, frequent follow-up examinations will be necessary, with additional tests as needed.CAN THE DISEASE BE TREATED/CURED?The majority of children with Kawasaki disease recover; however, some patients develop heart complications despite adequate treatment. The disease cannot be prevented, but the best way to reduce coronary complications is to diagnose the disease early and initiate treatment promptly.HOW IS IT TREATED?A child with a definite Kawasaki disease or a strong suspicion of this disease should be admitted to a hospital for observation and investigation for possible cardiac involvement. To minimize cardiac complications, the child should begin treatment immediately after the diagnosis. Treatment consists of aspirin and intravenous (IV) gamma globulin, both in high doses. Both medications will reduce inflammation in the body, thus alleviating the acute symptoms. High doses of gamma globulin are an essential part of the treatment, as it has been shown that coronary artery abnormalities occur in a large proportion of patients. Corticosteroids may sometimes be indicated, but less frequently.WHAT ARE THE SIDE EFFECTS OF THE TREATMENT?IV gamma globulins are generally well tolerated. Aspirin can cause stomach upset and a temporary increase in liver enzymes.
How long should treatment be continued?
High-dose IV gamma globulins are administered once in most patients; sometimes a second dose is necessary.
High-dose aspirin is administered initially, as long as fever persists. The dose is then reduced. This low dose has an anticoagulant effect on the platelets. This means the platelets do not stick together. Therefore, it is effective in preventing thrombi (blood clots) within aneurysms. Thrombi within aneurysms can lead to a heart attack, the most dangerous complication of Kawasaki disease. A child without coronary artery disease will take low-dose aspirin for a few weeks, but children with aneurysms must take aspirin for a longer period.WHAT DO THE FOLLOW-UP CHECKS LOOK LIKE?In children with Kawasaki disease, frequent blood tests are necessary until the erythrocyte sedimentation rate (ESR) and other values return to normal.
Frequent echocardiograms are necessary to detect any coronary aneurysms and monitor their progression. The frequency of these echocardiograms depends on the presence and size of the aneurysms. Most aneurysms resolve.
The general pediatrician, pediatric cardiologist, and pediatric rheumatologist will be responsible for patient follow-up. In hospitals without a pediatric rheumatologist, general pediatricians, along with cardiologists, will monitor patients, especially those with cardiac involvement.HOW LONG DOES THE DISEASE LAST?Kawasaki disease has three phases:
1. The acute phase, which encompasses the first two weeks during which fever and the aforementioned symptoms are present.
2. The subacute phase, from the second to the fourth week. This is the period in which platelet counts begin to increase and aneurysms may develop.
3. The recovery phase, from the first to the third month, during which altered blood counts normalize and some blood vessel abnormalities (coronary aneurysms) disappear or decrease in size.WHAT IS THE LONG-TERM PROGNOSIS OF THE DISEASE?The majority of patients have an excellent prognosis. They will lead normal lives and experience normal growth and development. The prognosis for patients with persistent coronary artery disease depends primarily on the development of stenosis and occlusion (narrowing of the blood vessels due to the formation of blood clots within them).
SOME RULES REGARDING SPORTS AND VACCINATIONS.
It is recommended that children with Kawasaki disease not be vaccinated until at least 3 to 6 months after the illness, as the disease and IV gamma globulins affect the immune system. This effect can last up to 6 months.
For children without heart defects, there are no restrictions on participating in sports or other daily activities. Children with coronary aneurysms should consult a pediatric cardiologist regarding participation in strenuous activities during adolescence.
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