Brief overview
- Treatment: Vascular inflammation can be controlled with antibodies and glucocorticoids by medication, and administration of acetylsalicylic acid (ASA) inhibits blood clotting and reduces the risk of heart attack.
- Symptoms: Persistent high fever with no clear cause, highly red lips, tongue and oral mucosa, skin rash, bilateral nonlateral conjunctivitis, lymph node swelling.
- Causes: Causes are unknown; genetic factors and excessive activity of the immune system probably play a role.
- Diagnosis: Important clues are provided by the characteristic symptoms and elevated inflammation levels in the blood. In addition, an examination of the heart by ECG and ultrasound is advisable.
- Course and prognosis: If diagnosed and treated early, the prognosis is usually good, although late complications, especially of the heart, are possible.
- Prevention: Kawasaki syndrome cannot be prevented because the cause is unknown.
Kawasaki syndrome is an acute inflammatory disease of the small and medium-sized blood vessels. In most cases, it is young children who experience Kawasaki syndrome; the condition is very rare in adults. It is not known exactly why the inflammation occurs. Doctors suspect that it is an overreaction of the immune system, possibly resulting from previous infections.
In contrast, the vascular inflammation of Kawasaki syndrome itself does not involve pathogens. The disease affects the entire body and all organs, but the heart and coronary arteries are particularly at risk.
Pediatricians consider Kawasaki syndrome to be a rheumatic disease in the broader sense. More precisely, it belongs to the vascular inflammations (vasculitides). Another name for Kawasaki syndrome is “mucocutaneous lymph node syndrome.”
In Germany, nine out of 10,000 children contract Kawasaki syndrome every year. In Japan, the rate of the disease is more than 20 times higher. The cause is not known. Four out of five sufferers are children between the ages of two and five. Boys are more often affected by Kawasaki syndrome than girls.
What to do about Kawasaki syndrome in children?
Standard treatment for Kawasaki syndrome is therapy with antibodies (immunoglobulins). These are artificially produced proteins that curb the inflammatory reaction and bring the immune system back on track. If administered in time, vascular damage to the heart can be largely avoided, and complications are therefore much less frequent.
To reduce fever and inhibit blood clotting, the doctor usually prescribes additional acetylsalicylic acid (ASA). Experts believe that this will further reduce the number of heart attacks – the most common cause of death in Kawasaki syndrome.
If the disease does not respond adequately to these drugs, other anti-inflammatory agents are available to control Kawasaki syndrome, such as tumor necrosis factor-alpha and interleukin-1 inhibitors.
If coronary arteries have already ruptured or occluded, it may be necessary to use a catheter or surgery to restore blood supply to the heart. However, this is rarely the case. In such an intervention, the physician inserts the patient’s own healthy vessel sections or artificially manufactured vascular prostheses. In addition, so-called stents can be used. These are small braided tubes that support the affected artery from the inside.
What are the symptoms of Kawasaki syndrome?
Kawasaki syndrome hides a variety of symptoms, because the disease may affect almost every organ. Nevertheless, there are five main symptoms, which in their combination are very typical for the disease. They often do not occur at the same time, but offset in time to each other.
- In all cases, there is a fever above 39 °C for more than five days. What is special about this fever is that no cause can be determined. Often bacteria or viruses are the cause of fever, but in Kawasaki syndrome there is no causative pathogen. Therefore, even antibiotic therapy does not reduce the fever.
- The mucous membranes of the mouth, tongue and lips are bright red in 90 percent of affected children. Doctors refer to these symptoms as patent lips and a strawberry or raspberry tongue.
- Very often, bilateral conjunctivitis occurs. Both eyes are reddened and small red vessels can be seen in the white of the eye. In Kawasaki syndrome, there is no pus formation because no bacteria are involved in the inflammation. Therefore, purulent conjunctivitis would argue against Kawasaki syndrome.
- In about two-thirds of affected children, the lymph nodes in the neck are swollen. This is a sign that an inflammatory reaction is taking place in the body and the immune system is activated.
- There may be other symptoms of Kawasaki syndrome, such as joint pain, diarrhea, vomiting, headache, pain when urinating, or chest pain.
Causes and risk factors
The causes of Kawasaki syndrome are largely unknown. Researchers suspect that an overreaction of the body’s defense system is behind it. In this case, unknown factors trigger an inflammatory reaction in the blood vessels that damages the vessel wall. Some experts assume that the cells of the blood vessels themselves overreact and in this way an inflammation develops.
A genetic component is also thought to play a role. The possible genetic component was discovered because siblings of a child with Kawasaki syndrome are more likely to develop Kawasaki syndrome themselves.
Investigations and diagnosis
The diagnosis of Kawasaki syndrome is based primarily on clinical symptoms. There are no specific tests for the disease. If five of the following six major symptoms are present, there is a high probability of having Kawasaki syndrome:
- High fever for more than five days
- Skin rash
- Redness of the oral mucosa
- Mostly bilateral conjunctivitis
- Lymph node swelling
If Kawasaki syndrome is suspected, it is important to examine the heart closely. In particular, an electrocardiogram (ECG) and cardiac ultrasound are necessary to detect possible damage to the heart muscle and valves early. In some cases, the doctor also performs a coronary angiography, in which he visualizes the coronary vessels with a contrast medium and examines them for damage, especially bulges (aneurysms).
There are also some signs in the blood that help the attending physician make a diagnosis. For example, the so-called inflammation values (leukocytes, C-reactive protein and the erythrocyte sedimentation rate) are elevated and indicate an inflammatory process. Bacteria or viruses, on the other hand, are not detectable in the blood. Otherwise, blood poisoning (sepsis) would be more likely to be suspected.
Course of the disease and prognosis
Since vascular inflammation in Kawasaki syndrome sometimes affects all organs, the course of the disease varies greatly from child to child. However, with early diagnosis and rapid initiation of therapy, the prognosis of Kawasaki syndrome is favorable: the smaller the damage to the vessels, the lower the likelihood of long-term consequences due to the disease. With timely therapy, about 99 percent survive Kawasaki syndrome, even if the long-term consequences cannot yet be estimated.
Particularly dangerous are the possible complications to the heart. These include, above all:
- Inflammation of the heart muscle (acute myocarditis)
- Constriction of the coronary arteries (stenosis)
- Death of parts of the heart muscle (myocardial infarction)
- Inflammation of the pericardium (pericarditis)
- Cardiac arrhythmias
- Formation of aneurysms
- Rupture of an aneurysm
Myocarditis, which may cause long-term damage to the heart and heart muscle, usually develops during the acute phase of the disease. In contrast, infarctions and bulging of the vessel walls (aneurysms) usually occur only a few weeks after the onset of the fever. The most common cause of death in Kawasaki syndrome is myocardial infarction.
To assess long-term damage, the physician looks for irregularities inside the coronary arteries after the disease has been overcome. This examination shows if and where aneurysms may be forming in the vessel wall.
About half of all aneurysms regress on their own. Other bulges remain for life and pose a life-threatening risk because there is an increased risk of rupture and severe bleeding at the dilated vessel walls. Adults who suffered from Kawasaki syndrome as a child are therefore still at risk from the late effects on the heart years after the disease.
