(Acta Paediatr Jpn 1990; 32: 188

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191)

Bronchial Asthma in Singapore Children 0.M. Chay Department of Paediatrics, Tan Tock Seng Hospital, Singapore

The incidence of bronchial asthma admissions to Singapore’s major Paediatric Units has increased over the years. The diagnosis of asthma was usually simple but patients with atypical presentations required the demonstration of bronchial lability to confirm the diagnosis. National statistics revealed a small but constant number of deaths from asthma in childhood. Underestimation of severity and delay in treatment were important contributing factors to deaths from asthma. Key Words Bronchial asthma, Children

Introduction Bronchial asthma is a major chronic disorder in Singapore. The aims of this study were (1) to establish the trend of asthma admissions in the two major Paediatric Departments in Singapore, (2) to review the outpatient management of bronchial asthma and (3) to examine the mortality from asthma in Singapore.

Method This paper reviews the following:(1) Data on hospital admissions from the two major Paediatric Departments in Singapore, Tan Tock Seng (TTSH) and Singapore General Hospital (SGH). Monthly admission statistics were available at TTSH only.

Received June 30, 1989 Correspondence address: Dr. O.M. Chay, Department of Paediatrics, Tan Tock Seng Hospital, Moulmein Road, Singapore 11 3 0

(2) Management at the Specialist Asthma Clinic in the hospitals. A study on the clinical features, laboratory tests and therapeutic trial of bronchodilators was made on 15 patients with chronic cough as the main manifestation of asthma. (3) National statistics on asthma mortality. This was based on data from the National Registration of Births and Deaths Bureau, Republic of Singapore, 1976-1986. Computerized records were only available for the period from 1984- 1986. Results

Inpatient Data There was an upward trend in the incidence of asthma admission from 8.9% to 13.2% in TTSH and 5 6% to 14.6%in SGH. The admissions in TTSH showed a bimodal pattern with peaks at the beginning and end of the year. The average admission was highest in February (2.9 per day) and lowest in June (1 per day). Complications were uncommon among inpatients. Status asthmaticus was not frequently seen and respiratory failure requir-

Bronchial asthma in Singapore children (73) 189 ing ventilatory support was even rarer. Minor complications recorded included lung collapse from mucus plugging, pneumothorax, pneumediastineum and subcutaneous emphysema. Deaths in hospitals were very rare.

Specialist Asthma Clinic Between 1985 and 1987, 122 patients were seen at the Specialist Asthma Clinic. The treatment of these 122 patients is shown in Tables 1-3. A large number of these patients had accepted the use of metered aerosol inhalers of beta agonist and steroids. Bronchodilators remained the mainstay in treatment in 86% of patients with frequent episodic asthma. 57% of patients with persistent asthma had prophylactic agents, of which 19 out of 26 were inhaled steroids. Study on Chronic Cough as the Main Manifestation of Asthma. There were 15 patients referred for confirmation and management of asthma, and their chief complaint was cough for more than 4 weeks. The mean age of this group was 6 years (range 2.8 years - 9.5 years). There were more males than females (2: 1). Of the 15 patients, 86% said asthma attacks were precipitated by cold drinks / food and 80% had preceding upper respiratory tract infections. Nocturnal exacerbation was seen in 60% of patients. The most common physical finding on examination was eczema (8 out of 15). Three patients had wheeze on ausculation although there was no such history. Only 9 patients were able to perform pulmonary function tests (Table 4). Bronchial provocation tests were performed when the children were well, following standard guidelines (1, 2). Treadmill exercise was not done. Corridor running was used for the exercise challenge test. All 15 patients, including one child with a negative histamine response, had a trial of bronchodilators. 14 patients had a good clinical response, including the one child with a negative histamine response. One patient did not attend follow-up.

Table 1. Treatment of infrequent episodic asthma (N = 41) INTERMITTENT BRONCHODILATORS Table 2. Treatment of frequent episodic asthma (N = 35) Bronchodilators Alone

11 2 12 5 30

Bronchodilators with Prophylactic Agents ~~

N = 5 (14%) Sodium Cromoglycat e Ket ot ifen Total

2

3 5

Table 3. Treatment of persistent asthma (N = 46) Bronchodilators Alone Beta-2 Aerosol Long-acting Theophylline Combination Total

N = 20 (43%) 3 3 14 20

Bronchodilators with Prophylactic Agents

N = 26 (57%) Steroids - Inhaled Oral + Inhaled Sodium Cromoglycate Ketotifen Total

17 2 6 1 26

Table 4. Laboratory investigations of chronic cough (1) Bronchial Provocative Tests (N = 6) Histamine Challenge Exercise Challenge

(2) Bronchodilator Response

Vol. 32 No. 2 April 1990

N = 30 (86%)

Beta-2 Aerosol Beta-2 Nebulization Longacting Tneophylline Combination Total

Positive 3 2

Negative 1 -

Positive 3

Negative -

190 (74) Chay

Mortality from Bronchial Asthma - National Statistics From 1976-1986, there were 68 deaths from asthma in patients aged under 19 years, These deaths were distributed throughout childhood (Table 5). From 1984-1986, there were 17 deaths (male 9, female 8) from bronchial asthma in children aged between 1-19 years. 88% of deaths occurred before arrival at the hospital: seven deaths (41%) occurred at home and six (35%) were dead on arrival at the hospital and two (12%) died on the way to consult a doctor. The two patients who died in the ward were in circulatory collapse on admission, and died soon after. Patients with rapid onset of asthma were at higher risk; seven (41%) died within 24 hours from the onset of symptoms. Eight deaths (47%) occurred between 12 midnight and 6 AM. There were three patients who had had symptoms for more than 48 hours and had not sought medical treatment. The majority were seen either by general practitioners or traditional therapists, although they had problematic asthma as revealed by the past medical history.

Discussion Bronchial asthma is a common disorder in Singapore children. With the decline in admissions from problems related to malnutrition and infection, the incidence of asthma among hospital admissions has steadily increased over the years. With increasing awareness among doctors of atypical presentations of asthma [3] ,more cases will be diagnosed. Asthma admissions occurred throughout the year but with seasonal fluctuations. The peak admissions were in October and February, and lowest in the middle of the year. Higher admissions occurred in the wet rainy months when respiratory infections were more common. Treatment of hospital patients was usually simple and effective. The emphasis was on frequent nebulization with a beta-agonist. The cumulative effects of multiple doses have been found to be effective in our patients [4]. Status

Table 5. Distribution of asthma deaths by age group (N = 68) AgeCroup

Under

No. of Deaths

yr yr

11 13

yr - 14 yr

14

15 - 19 yr

25

-

-

5

68

asthmaticus was successfully treated with vigorous nebulization and IV aminophylline and hydrocortisone. Respiratory failure was rare and ventilatory support was rarely required. Hospital mortality was negligible. The majority of patients at the Asthma Clinic had a typical presentation with recurrent wheezing (65%). There was a group of children (29%) who had chronic cough as the main manifestation. To confirm the diagnosis of asthma in this group, demonstration of bronchial lability by pulmonary function tests was carried out. A trial of bronchodilators was found to be another useful diagnostic pointer. Under-treatment had been observed in the patients referred for control of asthma. This is not only peculiar to our community [5, 61. Traditionally, our community will not accept long-term medication as most believe that too much “Western medicine” weakens the child and affects his growth and intellectual development. Aerosol devices have been well accepted by Westem countries but are viewed with great caution in Singapore, even among some doctors. At the Asthma Clinic, the author spent time trying to educate parents and patients on the disease, including simple measures to reduce the risk of exposure to non-specific allergens, the correct use of an inhaler, and problems such as recognition of a severe asthmatic attack. With better rapport, the parents were more likely to accept the advice given and to continue being followed-up. Contrary to the belief that deaths from asthma in children are uncommon, national

Acta Paediatr Jpn

Bronchial asthma in Singapore children (75) 191 statistics show that a small but constant number of children die from asthma each year. Like other centers we have not seen a decline in asthma deaths in spite of better medication being available in recent years [7]. The patients with rapid onset asthma were at a greater risk and succumbed within 24 hours. Most deaths occurred between 12 midnight and 6 in the morning. T h s period is known to be troublesome for asthmatics due to exaggerated diurnal variation in airway calibre in these patients [8]. Unfortunately, at this time of the day in Singapore, public transport is not easily available. This could have contributed to the delay in seeking medical assistance. Similar to other reports [9 , lo], underestimation of the severity of acute symptoms and delay in obtaining medical assistance were two important factors contributing to asthma deaths. Therefore, further education of the public and doctors is necessary. We hope to promote the use of the minipeak flow meter to improve the recognition of acute wheezing 1111. Acknowledgements The author thanks the doctors of the Paediatric Departments, TTSH and SGH, for their kind assistance in this study, and the staff of the National Registration of Births and Deaths, Republic of Singapore, and of the Pathology Department, SGH, for their co-operation.

VoZ. 32 No. 2 April 1990

References

1. Eiser NM, Kerrebjin KF, Quanjer PH. SEPCR Working Group (Bronchial Hyperreactivity). Guidelines for Standardisation of Bronchial Challenges with nonspecific Bronchoconstricting agents. Clinical Respiratory Physiology 1983; 19: 495-514. 2. Silverman M, Anderson SD. Standardization of Exercise Tests in Asthmatic Children. Arch Dis Child. 1972; 47: 882-889. 3. Carrao WM, Braman SS, Irwin R S . Chronic cough as the sole presenting manifestation of bronchial asthma. N Engl J Med. 1979; 300: 633-637. 4 . Britton J, Tattersfield A. Comparison of cumulative and non cumulative techniques to measure dose - response curves for Beta - agonist in patients with asthma. Thorax 1984; 39: 597599. 5. Clover AF. Community campaign against asthma. Arch Dis Child. 1984; 59: 449-452, 6. Speight ANP, Lee DA, Hey EN. Underdiagnosis and undertreatment of asthma in childhood. Br Med J. 1983; 286: 1253-1256. 7 . Phelan PD, Landau LI, Olinsky A. Respiratory Illness in Children 2nd edition Chapter 6 Asthma: Definition. Blackwell Scientific Publications 1982. 8. Brans PJ. Nocturnal asthma - mechanism and causes. Br Med J 1984; 288: 1397. 9 . Johnson AJ, Nunn AJ, Stableforth DE, Stewart CJ. Circumstances of death from asthma. Br Med J 1984; 288: 1870-1872. 10. Carswell F. Thirty deaths from asthma. Arch Dis Child 1985; 60: 25-28. 11. Sly PD, Landau LI, Weymouth R. Home recording of peak expiratory flow rates and perception of asthma. Am J Dis Child 1985; 139: 479-481.

Bronchial asthma in Singapore children.

The incidence of bronchial asthma admissions to Singapore's major Paediatric Units has increased over the years. The diagnosis of asthma was usually s...
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