HEALTHNET

Kawasaki Disease

Yee Ling's one-year-old youngest son was looked after by his grandmother during the daytime. One afternoon, he developed a high fever. His grandmother gave him some anti-pyretics and he seemed fine. However, the baby was still running a fever the next day. Yee Ling took her boy to the doctor and was told that the baby had the flu. The doctor reassured Yee Ling, prescribed some medication and advised Yee Ling to keep the baby well hydrated. Unfortunately, the fever did not respond to the medication. In addition, the baby had developed red eyes and lips and a rash on his palms. Realising that the baby had been having a high fever for five days, Yee Ling took him to the Accident and Emergency Department. The duty doctor told Yee Ling that her son might be suffering from Kawasaki disease and he was admitted to the Pediatric Ward immediately.

A fatal disease which can damage heart arteries
Low local incidence with 100 cases annually
Medical attention is needed if high fever and rashes are experienced
Medical treatments and ultrasound monitoring
Relapse is possible with no preventive measure at hand

Source: Dr Jeremy C. C. Hung, Specialist in paediatrics

A fatal disease which can damage heart arteries

Some parents may have heard of Kawasaki disease. However, without knowing much about the disease, they might be unduly worried about their children catching the disease. The name "Kawasaki" originates from Dr. Tomisaku Kawasaki, the Japanese pediatrician who discovered a new disease among children in 1961. The disease causes symptoms on skin, conjunctival and oral mucous membranes, lymph node, etc. Subsequent to his research report on 1967, the newly discovered disease officially became his namesake.

"Kawasaki Disease" can be categorised as an acquired heart disease with a grim possibility of cardiovascular complications. Currently, the actual cause of "Kawasaki Disease" is unknown. It is generally believed to be an abnormal reaction of the immune system against an infection (bacterial or viral). The immune system attacks the blood vessels and causes inflammation to the blood vessel walls (vasculitis). The damage will result in localised weakening and thinning of the blood vessel walls, which may balloon up, i.e. develop into arterial aneurysms, when sujected to prolonged pressure. On the other hand, injured blood vessel walls may cause scarring and narrowing of the blood vessels. The two vascular abnormalities can lead to blood clots forming inside the vessels and resulting in myocardial infarction (heart attack) and a risk of death. Another cause of death is the rupture of the coronary artery aneurysm and uncontrollable bleeding from the rupture site.

Low local incidence with 100 cases annually

"Kawasaki Disease" is uncommon in Hong Kong. Among the age group of 5 or under, about 39 children out of 100,000 suffer from the disease. There is on average 1 patient in every 2,500 children in Hong Kong with 100 new cases reported per year. Though the disease can affect all ages, Kawasaki Disease is predominantly a disease of younger children with a large proportion of patients less than one year of age. Statistic shows that the disease affects boys more than girls with a ratio of 1.7 to 1.

Medical attention is needed if high fever and rashes are experienced

Important symptoms of "Kawasaki Disease" include:

High fever of 39-40°C that lasts for 5 or more days
Red eyes
Red or peeling oral mucous membranes, including lips
Rashes on the body or limbs
Red, swollen or peeling skin, especially around the nails
Acute non-infective swollen lymph nodes

Since the cause of Kawasaki Disease is unknown its diagnosis is mainly through astute clinical observations. Once the above mentioned symptoms are observed, parents should seek medical attention right away. Kawasaki disease is confirmed if the patient has at least 5 of the above symptoms. Sometimes, the symptoms in the early course of disease may not be obvious. The doctors may need to carry out blood tests, electrocardiogram, echocardiogram, chest X-rays, and magnetic resonance angiography to investigate the illness.

Medical treatments and ultrasound monitoring

The standard treatments for Kawasaki disease are gamma-globulin infusion and oral aspirin. The gamma-globulin infusion may take up to 4 days. Its side effects include hypertension and allergic reactions. Oral aspirin may be taken for 6-12 weeks. Since influenza can trigger off severe compliations in children taking aspirin, it is recommeded that the child should be given influenza vaccination. Aspirin can aslo cause stomach ulcer.

A repeat echocardiogram will need to be done 1 month after the onset of fever, to monitor the presence or progress of coronary (heart) artery aneurysms. The child's activities may need to be restricted in the first three months. Further restriction of activities will depend on the degree of heart involvement.

Parents may ask the doctor, if my child's arteries are affected by the inflammation, will their function be impaired in the future? If the follow up ultrasound scans shows that there is no evidence of aneurysms, the child is expected to recover fully. However, if the aneurysms persist, further treatment may be required which may entail taking low dose aspirin for a long period of time. Surgery may be needed if the arteries are severely narrowed or blocked.

Relapse is possible with no preventive measure at hand

Most patients recover from the disease fully and no restriction of activities or special treatments are needed. However, parents should be aware that Kawasaki disease has a relapse rate of 1-4%. As mentioned before, Kawasaki disease can be lethal. Deaths usually result from heart attacks especially when treatment is delayed. Fortunately, the death rate is low at 0.1-2%.

At presence, there is no preventive measure one can adopt to prevent Kawasaki disease. In a nutshell, parents are advised to pay attention to the well beings of their children. The best outcome requires early medical attention should the above combination of symptoms are observed.

Source: Dr Jeremy C. C. Hung, Specialist in paediatrics