The signs of Kawasaki syndrome are similar to those of scarlet fever. But what symptoms indicate Kawasaki syndrome? Typically, there are three phases with different symptoms, although the duration may vary depending on the start of treatment and individual course.
Kawasaki: symptoms in the acute phase (up to ten days).
Five main criteria (as signs of acute inflammation) are distinguished in addition to the typical fever; if at least four of these are fulfilled, the diagnosis of Kawasaki syndrome is considered certain. However, especially in young children, fewer symptoms may be present; in that case, high fever that persists for more than five days despite treatment is a particularly important clue:
- The disease begins with a fever above 39 °C that lasts longer than five days and does not respond to antibiotics. In most cases, the fever rises and falls alternately over a period of one to three weeks.
- Redness and non-purulent conjunctivitis of both eyes, respectively, set in after about two days.
- Within about five days, dry, highly red lips (lacquer lips) and a red tongue (strawberry tongue or raspberry tongue) appear. A diffusely reddened oral mucosa without purulent coatings may also appear.
- Other signs are redness or blue discoloration and swelling of palms and soles, later scaling and peeling of the skin on the fingertips and toes (after about two to three weeks).
- It shows temporary, multiform, often patchy rash (exanthema), especially on the trunk and In the diaper and genital area, which resembles measles or scarlet fever.
- There may be swelling of the cervical lymph nodes and redness of the neck.
In addition, there may be signs of inflammation in other organs, for example, the gastrointestinal tract (vomiting, diarrhea, abdominal pain), joints (pain), urinary tract (discomfort during urination), meninges (neck stiffness, headache) or nerves (paralysis, hearing problems), heart or liver.
Subacute phase of Kawasaki syndrome (approximately two to four weeks).
In this phase, fever, rash, and lymph node swelling decrease; conjunctivitis, loss of appetite, and irritability may still persist. New possible symptoms in this phase are a – typical – crescent-shaped scaling of the tips of the fingers and toes and joint pain. On examination, enlargement of the gallbladder due to congestion of bile (hydrops) and bulging of large vessels may now be palpable.
Convalescent phase (up to 70 days after onset of illness).
During this time, at best, all symptoms resolve and the erythrocyte sedimentation rate normalizes. Fatigue and poor performance may occasionally occur during this time.
What are the complications?
The later the disease is detected and treated, the greater the risk for complications. Ultimately, any organ can be affected by the inflammation – so the list of possible complications is long. However, the most common and also the most feared are the bulging of the aorta (aortic aneurysm) and other, possibly life-threatening disorders of the heart. However, the pancreas or kidneys can also be affected. Although Kawasaki syndrome is comparatively rare, it is now the most common cause of acquired heart disease in childhood in industrialized countries. These include:
- Bulging and calcification of the coronary arteries and aorta, which can burst, leading to a heart attack or hemorrhage (even months to years later)
- Inflammation of the heart muscle or pericardium, pericardial effusion.
- Cardiac arrhythmia
- Heart valve problems
- Heart failure
If Kawasaki syndrome is left untreated, about a quarter of children develop heart problems. Other possible complications include inflammation of the brain (meningitis), liver, ears, eyes urethra or gall bladder. Usually, these symptoms resolve without consequences.
Kawasaki syndrome: how is it diagnosed?
Because Kawasaki syndrome can have life-threatening consequences in children, timely diagnosis and early initiation of treatment are critical. If Kawasaki syndrome is suspected, the child is hospitalized. Since laboratory findings are overall quite nonspecific, the diagnosis is made predominantly on the basis of symptoms, especially in the acute phase.Nevertheless, there are a number of different examinations that are performed, also to rule out other causes and complications and to monitor the course of the disease. These include, above all, blood tests (blood count, inflammatory signs, antibodies, blood sedimentation rate and others), the taking of blood cultures, an electrocardiography (ECG) and an ultrasound examination of the heart. A throat swab may also be taken.
What treatment is available for Kawasaki disease?
The goal of treatment is to reduce the inflammatory processes and thus the rate of complications. It is crucial to start therapy before the tenth day of illness – studies have shown that the incidence of changes in the heart is then reduced by a factor of 10. To stimulate the immune system, an infusion of immunoglobulins is given once (rarely twice) over six to twelve hours. In addition, treatment is carried out with acetylsalicylic acid, which is administered in high doses for about two weeks, followed by a lower dose for six to eight weeks or – if there are outpouchings – for several months, after which it may be replaced by anticoagulants. Sometimes anti-inflammatory steroids (cortisone) are also used. Long-term treatment is required for coronary artery problems. Acetylsalicylic acid (in aspirin) should not normally be given to children because it can lead to what is known as Reye’s syndrome, especially when combined with viral infections such as chickenpox or influenza. Therefore, children with Kawasaki syndrome should be vaccinated against influenza and chickenpox to prevent Reye syndrome as a sequelae.
What is the course and prognosis?
The prognosis depends primarily on the extent to which the heart is affected. In most cases, the disease heals without sequelae. Since therapy with immunoglobulins was introduced, the prognosis has improved many times over, even with organ involvement. Even pre-existing changes in the coronary arteries can regress as a result. The original mortality rate of one to two percent has been reduced to the current 0.4 percent. It is still unclear to what extent coronary vessels whose changes have regressed (or were not visible at all) are more susceptible to disease and whether the risk of arteriosclerosis is increased in adulthood. Therefore, affected individuals undergo long-term cardiological follow-up. In the rare case of a fatal course, death usually occurs within the first six months but may occur many years later.
