Kawasaki disease is a childhood disease that causes inflammation of the blood vessels (vasculitis), including arteries, veins and capillaries. It can affect any part of your child’s body, and can cause damage to your child’s heart.
Kawasaki disease is the most common cause of acquired heart disease in children in the developed world and occurs mostly in children of Asian and Pacific Island descent. It usually affects children under five and is more common in boys than girls.
Most children make a full recovery from Kawasaki disease after several weeks. However, associated heart complications mean that some children are left with long-term health problems or, very rarely, die because of damage to their heart. A very small number of children may get the disease again.
The disease is named after the Japanese doctor, Dr Tomisaku Kawasaki, who first identified it in 1961.
The exact cause of Kawasaki disease is unknown despite much research.
Kawasaki disease doesn’t have a unique symptom, which is why it’s difficult to diagnose. However, the main symptom of Kawasaki disease is a sudden fever which is higher than 39°C (102.2°F) and lasts longer than five days. Your child may also be much more irritable than at other times when he or she previously had a fever. The other main symptoms your child may have are:
Not all the symptoms of Kawasaki disease may show, or they may not show all at the same time; it’s therefore very important that if your child has any of these symptoms, see your GP immediately.
You may also notice that your child has other symptoms, including:
Kawasaki disease can cause severe damage to your child's heart and blood vessels. Without treatment about one in four children go on to develop heart disease.
The arteries in your child's heart can become inflamed causing a coronary artery aneurysm. This is when a main blood vessel supplying blood to the heart muscle becomes damaged and swells because the artery wall is weakened by inflammation. This creates a balloon-like bulge in the artery which can burst and be fatal. Damage to the vessel can also increase the risk of a clot forming. A severe clot can stop blood flow to the heart muscle and cause a heart attack.
Further damage to the heart can occasionally develop in the later stages of the disease as your child's body tries to heal itself. Complications can include thrombosis (a blood clot within a blood vessel), stenosis (when a blood vessel narrows) or problems with your child’s heart beat. These reduce or stop blood flow to the heart altogether, which can cause reduced ability of the heart to contract properly, or a heart attack.
All these can lead to long-term health problems for your child, and in rare cases, can be fatal. Kawasaki disease can potentially cause problems in adult life too, including heart attack, heart disease, or a ruptured aneurysm. However, the risk of long-term complications isn't yet fully known.
Doctors still don't know what causes Kawasaki disease. However, it may be linked to how the body responds to a virus or infection. It may also be genetic – some children may be genetically more susceptible to the disease than others. The exact role of these factors, however, is unknown. Kawasaki disease itself isn’t contagious and can’t be passed from one child to another.
Kawasaki disease can be difficult to diagnose as many of the symptoms overlap with those of other common childhood diseases, such as scarlet fever and measles. There are currently no tests available that can confirm the condition.
Your GP may suspect your child has Kawasaki disease if he or she:
However, because it’s so important to diagnose Kawasaki disease early, your GP may diagnose what is known as incomplete Kawasaki disease. For example, if your child has had a fever for more than five days but only has two or three main symptoms or no other diagnoses seems likely. This is because the symptoms may not appear at the same time, or the disease hasn't yet fully developed. This diagnosis is more often made if your child is under the age of one.
If your GP suspects that your child has Kawasaki disease, he or she will urgently refer your child to a paediatrician, a doctor specialising in children's health.
The paediatrician will review your child and the diagnosis. He or she may arrange for your child to have an echocardiogram. This uses an ultrasound probe, which is run over your child's chest to get a moving picture of the heart. The echocardiogram will show whether your child has developed a coronary artery aneurysm and how well the heart muscle is working.
Your child may have other tests including blood tests, X-ray and electrocardiogram (ECG) to see if the disease has affected your child’s heart.
Your child will be given treatment as quickly as possible after diagnosis because of the potentially damaging complications to your child’s heart.
Treatment aims to reduce the inflammation in your child's body to relieve symptoms and to prevent a coronary artery aneurysm from forming. This is done using two medicines – immunoglobulin and aspirin.
Immunoglobulin (also known as gamma globulin) is a concentrate of antibodies from a number of blood donors. It has been shown to be extremely effective in treating Kawasaki disease, and to greatly reduce the likelihood of a coronary artery aneurysm if it's given within 10 days of the symptoms starting.
Immunoglobulin is given as a single dose over a few hours. A smaller dose over five successive days may occasionally be given if heart complications are suspected. The doctor will inject the immunoglobulin into your child's vein using a cannula (a small plastic tube) and an infusion pump.
You will often see some improvement in your child within 24 hours. If your child's fever doesn't go down after 36 hours, your child’s doctor may give another dose of immunoglobulin.
If your child's fever continues after two courses of immunoglobulin treatment, your child may be given steroids. However, more research is needed to confirm their effectiveness.
Aspirin shouldn’t be given to children under the age of 16 except under very specific circumstances. For the treatment of Kawasaki disease, doctors believe the benefits of aspirin outweigh the harms.
Your child will be given four doses of aspirin to take at regular intervals through the day. It's important that you follow your doctor's instructions precisely when giving your child medicines.
Once your child's fever has settled, the dose of aspirin can be reduced. However, he or she will need to continue taking regular doses for a minimum of a further six weeks. The length of time your child will need to continue taking aspirin depends on whether or not his or her coronary arteries have been damaged. If there is damage, your child may need to take aspirin for much longer.
Most children recover from Kawasaki disease if they receive early treatment and some children have heart problems that are only temporary. However, if your child does have lasting heart damage, he or she will need further long-term monitoring and treatment such as:
The duration of monitoring and ongoing treatment will depend on how severely your child’s heart has been affected. Very rarely, your child may need surgery such as:
Produced by Natalie Heaton, Bupa Health Information Team, September 2012.
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