NG Yin Ming

Kawasaki disease (KD) has become one of the most common acquired heart disease in children in Hong Kong. Hong Kong pediatricians started to be more aware of Kawasaki disease since 1982 and they reported Kawasaki disease in the local journals as early as 1985. Initial series showed high coronary artery aneurysm (CAA) rate because more severely affected patients were admitted in the hospitals. Recent reports from various workers in Hong Kong has demonstrated that the disease has similar clinical features like other world series and it is quite common in Hong Kong Chinese. The incidence was reported to be about 25 per 100,000 children below 5 years.

Kawasaki disease is an acute febrile exanthematous disease of unknown aetiology affecting predominantly children between 2 month and 5 years of age. Diagnosis of Kawasaki disease is by clinical assessment and it needs to have five out of the above six criteria to make a firm diagnosis. The disease is typically presented with the following principle symptoms:

(1) high swinging fever of more than 5 days,
(2) non-purulent conjunctivitis,
(3) mouth changes,
(4) limb changes,
(5) skin rash and
(6) lymphadenopathy.

Besides the diagnostic criteria, diarrhoea is the most common presenting symptom. Some patients have atypical clinical features and they do not have sufficient (five) diagnostic criteria, and in this juncture, echocardiographic finding is an important adjunct in making diagnosis -- the group we often called "atypical Kawasaki disease". The younger the infants, the more atypical would be the clinical presentations and the higher chance of coronary arteries involvement.

Laboratory investigations are important adjuncts to the management (not diagnosis) of patients with KD. Most common laboratory abnormalities include: low haemogoblin count, leucocytosis, thrombocytosis and raised ESR.

Aspirin and intravenous gammaglobulin (IVGG) are the main-stay of treatment. We have found that the incidence of CAA decreases with the judicious use of IVGG.

KD patients < 6m are at a particularly increased risk for development of Coronary Artery Aneurysms (CAA) and Giant CAA. IVGG therapy by illness day 10 is associated with substantial reduction in the frequency of CAA and GCAA in this high risk population. There is no specific clinical or laboratory features was able to predict the development of CAA.

The most important and fearful complication is cardiac involvement, especially coronary artery aneursyms (CAA) and its sequalae like thrombosis, stenosis, and myocardial infarction. CAA can be diagnosed with echocardiography. It is necessary to perform selective coronary angiograms on those with large CAA and persistent abnormalities. We followed 18 patients with CAA from 2 to 14 years with angiograms and we were able to show the course and fate of the CAA very similar to Dr. H. Kato's series. Of the 18 patients who had angiograms performed, 2 have persistent stenosis of the RCA, one with LCA stenosis and multiple CAA, 4 others have persistent CAA which ranged from 4 mm to 10 mm. 2 patients with residual stenosis have Thallium nuclear scan performed which showed myocardial ischemia in one patient. The three patients who have coronary artery stenosis could only be demonstrated by angiography and not by routine 2-dimensional echocardiography.

A territory-wide registry of KD in Hong Kong would help to determine the actual incidence in this SAR and to obtain accurate data as regards clinical and laboratory features of KD in Hong Kong.