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Biomedical subjects

C M Wong

Publications and source records attributed to C M Wong.

At least 55 records · Page 3Linked to original sources
PubMed1999

Giant cell arteritis presenting as chronic cough and prolonged fever.

A 62-year-old man presented with a 3-month history of chronic non-productive cough and unexplained fever. Further questioning revealed that he had headaches and myalgia. Bilateral thickened temporal arteries were noted on physical examination. The erythrocyte sedimentation rate was 96 mm in 1 h. A biopsy specimen of the left temporal artery showed inflammatory changes consistent with the diagnosis of giant cell arteritis. Commencement of prednisolone resulted in rapid and dramatic resolution of his symptoms. Physicians should be aware of respiratory symptoms in patients with giant cell arteritis in order to avoid delay in diagnosis and therapy of this condition.

Chronic Disease↗
PubMed1999

Effects of ambient air pollution and environmental tobacco smoke on respiratory health of non-smoking women in Hong Kong.

BACKGROUND: Two-thirds of complaints received by the Hong Kong Environmental Protection Department in 1988 were related to poor air quality. In July 1990 legislation was implemented to reduce fuel sulphur levels. The intervention led to a reduction in respiratory symptoms and bronchial hyperresponsiveness of primary school children. The objectives of this study were to investigate the differences in respiratory health between non-smoking women living in the more polluted district (Kwai Tsing) and those living in the less polluted district (Southern); to assess the impact of the government air quality intervention; and to study the effect of environmental tobacco smoke on respiratory health in non-smoking women in both districts. METHOD: A total of 3405 non-smoking women, aged 36.5 years (standard deviation = 3.0), from two districts with good and poor air quality respectively before the intervention were followed yearly from 1989 to 1991. Binary latent variable modelling was used to summarize the six respiratory symptoms and to estimate the effects of risk factors. RESULTS: In 1989, living in the polluted district was associated with poor respiratory health (odds ratio [OR] = 1.55, 95% confidence interval [CI]: 1.11-2.17, P < 0.01). After the intervention, in the polluted district only, sulphur dioxide levels fell by up to 80% and sulphate concentrations in respirable particulates by 38%. Between 1989 and 1990-1991, there was no significantly greater decline (P > 0.241) in the more polluted compared with the less polluted district for poor respiratory health. In 1989, the effects on poor respiratory health for exposure to two or more categories of smokers relative to none in the home (OR = 1.80, 95% CI: 1.15-2.83, P < 0.01) were higher but not significantly than those for living in polluted relative to less polluted district (95% CI of the two effects overlapping each other). CONCLUSIONS: Environmental tobacco smoke (ETS) and outdoor air pollution had independent adverse effects on respiratory health of non-smoking women and improvement in air quality had produced some but non-significant benefits.

Adolescent↗
PubMed1999

Massive pleural effusions in cryptococcal meningitis.

Cryptococcal infection uncommonly presents with pulmonary manifestations and even more rarely so as massive bilateral effusions. Pleural involvement is usually associated with underlying pulmonary parenchymal lesions and is unusual while on antifungal therapy. We report a patient with cryptococcal meningitis who, while on intravenous 5-flucytosine and amphotericin B, developed life-threatening bilateral massive pleural effusions with evidence of spontaneous resolution, consistent with prior hypothesis of antigenic stimulation as the cause of pleural involvement.

Adult↗
PubMed1999

Attitudes and knowledge of newly diagnosed tuberculosis patients regarding the disease, and factors affecting treatment compliance.

SETTING: An urban university teaching hospital. OBJECTIVES: To determine patients' attitudes to tuberculosis and their knowledge of the disease, and factors associated with treatment compliance. DESIGN: All adult patients commenced on treatment for tuberculosis from September 1994 to February 1996 were interviewed on initiation of treatment. To assess patient compliance with treatment, hospital clinical records were reviewed retrospectively. RESULTS: A total of 135 patients with a mean age (+/-SD) of 41.9 (+/-17.4) years (range 15-84 years) were interviewed. The patients had limited understanding and knowledge about tuberculosis. There was a negative correlation between patient age and tuberculosis knowledge score (r = -0.18, P = 0.038). Patients with tertiary education had better knowledge than the others. Of 118 patients who were followed-up in our chest clinic, 80 (67.8%) completed the prescribed treatment. Compliance with treatment and follow-up was not affected by age, sex, ethnic group, educational level, occupation, extent of knowledge, tuberculosis symptoms, hospitalisation for tuberculosis or duration of the prescribed treatment regimen. There was a trend toward poorer compliance among patients who equated disappearance of tuberculosis symptoms with cure of the disease. CONCLUSIONS: Malaysian patients with newly diagnosed tuberculosis attending a university teaching hospital had misconceptions and limited knowledge about the disease and its treatment. Educational background was an important determinant of a patient's level of knowledge about tuberculosis. Compliance was not affected by patient characteristics. Adequate counselling and education of patients and close relatives on tuberculosis and the necessity for prolonged treatment may help to improve treatment compliance.

Adolescent↗
PubMed1999

Tuberculous pleurisy as a manifestation of primary and reactivation disease in a region with a high prevalence of tuberculosis.

SETTING: A teaching hospital in Malaysia. OBJECTIVE: To review the demographic and clinical features of patients with pleural tuberculosis (TB). DESIGN: Retrospective chart and chest radiograph review. RESULTS: The chest radiograph of 54 (61.4%) of a total of 88 patients with pleural TB did not show any lung infiltrate (considered a manifestation of primary TB), while that of 32 (36.3%) patients showed infiltrates in the upper lobes or superior segment of the lower lobes, or the presence of parenchymal scarring in the upper lobes (typical of reactivation TB). Additionally, the chest radiograph of two (2.3%) patients showed miliary mottling (also classified as having primary TB). The mean age of patients with primary versus reactivation tuberculous pleurisy was 36.3 (+/-14.8) years and 44.6 (+/-19.3) years, respectively (P = 0.041). The median duration of symptoms before presentation was 14 days and 60 days in patients with primary and reactivation disease, respectively (P = 0.001). CONCLUSION: In Malaysia, where the prevalence of TB is high, tuberculous pleurisy is more commonly a manifestation of primary rather than reactivation disease. Patients with primary TB pleurisy are younger and have a shorter duration of symptoms than those with reactivation TB pleurisy.

Adult↗
PubMed1999

Ectopic pregnancy: uncommon presentations and difficulty in diagnosis.

Diagnosis of ectopic pregnancy prior to rupture is an arduous task even with the availability of many new investigative methods and imaging modalities. Above all, a high index of suspicion is necessary when dealing with women who present in early pregnancy with abdominal pain and vaginal bleeding. With the increased use of ovulation induction agents, the probability of heterotropic pregnancy should be kept in mind. The use of transvaginal ultrasonography (TVS) will help in earlier diagnosis because of its advantages over transabdominal ultrasonography (TAS).

Adult↗
PubMed1998

Ki-ras codon 12 point mutational activation in Hong Kong colorectal carcinoma patients.

This study investigated the frequency and importance of Ki-ras codon 12 mutations in 99 Hong Kong Chinese colorectal carcinoma specimens by allele-specific oligonucleotide hybridization. The frequency of mutations detected was 30% and the most common mutation observed resulted in aspartic acid substitutions. Previous studies showed that specific Ki-ras mutations have been significantly associated with prognosis. Ki-ras codon 12 point mutational activation in CRC was significantly associated with the differentiation status of tumors in this study. Ethnic differences in the patterns of Ki-ras codon 12 point mutations were observed.

Adult↗
PubMed1998

Distal coronary artery perforation resulting from the use of hydrophilic coated guidewire in tortuous vessels.

We describe our experience with the ChoiCE PT (Boston Scientific Corporation, MN) guidewire, which resulted in perforation of the distal coronary artery in two instances. This newly introduced guidewire differs from earlier guidewires in its ability to cross lesions in tortuous arteries. However, when it buckles deep in the coronary artery, perforation can easily result. While the ChoiCE PT guidewire is a useful addition to our armamentarium in interventional procedures, it should be treated with care.

Aged↗
PubMed1998

Tobacco advertisements: one of the strongest risk factors for smoking in Hong Kong students.

STUDY OBJECTIVE: To describe the prevalence of smoking in junior secondary school students in Hong Kong and to analyse the relationship between a range of risk factors and ever-smoking experience, including tobacco advertisements. METHODS: Cross-sectional survey using an anonymous standardised self-administered questionnaire. SETTING: 61 randomly selected secondary schools in Hong Kong. PARTICIPANTS: 6,304 form 1 to 3 Chinese students from 172 classes (51% girls and 49% boys; 90% were aged 12 to 15 years). RESULTS: The smoking status (95% confidence interval) was: (1) never smoker, 71.1% (70.0%-72.2%), (2) tried only, 15.5% (14.6%-16.4%), (3) used to smoke but not now, 4.2% (3.7%-4.7%), (4) smoked < 1 cigarette per week, 2.9% (2.5%-3.4%), (5) smoked 1-6 per week, 1.7% (1.4%-2.0%), and (6) smoked > 6 per week, 4.5% (4.0%-5.0%). In a backward stepwise logistic regression model, ever-smoking (including categories 2 to 6 above) was independently associated with thirteen factors, including gender (boys), increasing age, place of birth (outside Hong Kong, mainly China), poor knowledge of the hazards of smoking, positive attitudes to smoking, smoking in family members, participation in tobacco promotional activities, and perception of cigarette advertisements as attractive. Among the strongest associations observed was the youth's perception of cigarette advertisements as attractive, with the adjusted odds ratio (95% confidence interval) of 2.68 (2.33-3.07). CONCLUSIONS: Smoking among young people is an important public health problem. Although the causes are multifactorial, in Hong Kong environmental tobacco advertising is an important risk factor that can be removed by banning all forms of tobacco promotion to young people.

Adolescent↗
PubMed1998

Technical hints for high dose rate interstitial tongue brachytherapy.

High dose rate (HDR) interstitial tongue brachytherapy is a new treatment modality. This study describes important technical details required for its successful use. Thirteen patients with carcinoma of the oral tongue were treated solely with interstitial brachytherapy using HDR remote afterloading techniques during the years 1994-1997. The afterloading catheters were positioned by the submandibular approach with the assistance of a template set. Custom-made mandibular lead shields were inserted prior to treatment. Special reusable Tuen Mun Hospital (TMH) lead buttons were made for improved radiation protection. The median dose given was 55 Gy in ten fractions over 6 days. The interfraction interval was 7 hours for the first seven patients treated and was extended to 8 hours for the other six. Shrinking field techniques were employed and the treatment length of the last fraction was reduced by 5 mm. Commencing with the second patient treated with double planar implants, the medial plane was treated with eight fractions while the lateral plane received ten fractions. To reduce further the potential risk of tract seeding, additional coverage to the implantation tracts was given for the last four patients, with the resultant isodose curves resembling a 'comb rake/brush'. The mean and median measured doses on the inner face of the mandibular shields were 113% and 93% of the reference dose respectively (range 77-247). The dose to the corresponding sites on the gingival surface can be reduced by 75% if the 3 mm thick lead shield is placed successfully. With the use of the TMH button, the transmitted dose to the tissue in direct contact can be reduced by one-third. With the 'comb rake/brush' dose distribution, the high dose volume of the single planar implants could be reduced by 44%, compared with the low dose rate technique, if loading to just 5 mm short of the submandibular skin was required. The mean doses for the combination of eight double planar plus two single planar implants, and ten double planar implants, are on average 29% and 37% greater than the reference dose respectively. An 8% reduction in absolute dose in the region between the planes of the catheters would lead to an even greater magnitude of reduction in morbidity to late responding tissue. The prerequisite for the success of HDR interstitial implants is to develop a good technique in positioning the afterloading catheters and protection of the normal tissue. Its importance merits special attention if HDR remote afterloading interstitial tongue brachytherapy is to realize its full potential.

Brachytherapy↗
PubMed1998

Respiratory symptoms due to active and passive smoking in junior secondary school students in Hong Kong.

BACKGROUND: Evidence on respiratory symptoms due to smoking and passive smoking in children is mainly derived from studies in Western countries. Evidence from the East was required to support stronger tobacco control policy in Asia. This study aimed to analyse the relationship between respiratory symptoms and smoking status in junior secondary students and between respiratory symptoms and family smoking in never-smoking students. METHODS: In a cross-sectional survey in 1994, anonymous questionnaires were administered to a two-stage cluster probability sample of 6304 students, aged mostly 12-15 years, from 172 classes of 61 schools in Hong Kong. RESULTS: Significant linear trends were found between smoking and the prevalence of throat and nose problems, cough and phlegm, and wheezing. The odds ratio (OR), after adjustment for age, gender, area of residence, type of housing and correlation within schools and classes (cluster effects), for smoking at least weekly ranged from 1.35 to 4.84. In never-smoking children, significant trends were found between the number of smokers living with the children and throat and nose problems, cough and phlegm, and recent wheezing. The adjusted OR and 95% confidence interval (CI) for any cough or phlegm symptoms was 1.19 (95% CI: 1.01-1.47) for one smoking household member, 1.38 (95% CI: 1.07-1.79) for two and 1.85 (95% CI: 1.19-2.85) for three (P for trend <0.001). Increased OR were found for father and mother smoking. CONCLUSIONS: This study provides strong evidence that both active and passive smoking can cause respiratory ill health in Chinese children in Hong Kong. Urgent measures are needed to protect children from the health hazards of active and passive smoking in Asia.

Adolescent↗
PubMed1998

Economic burden of environmental tobacco smoke on Hong Kong families: scale and impact.

STUDY OBJECTIVE: To examine the financial cost of doctor consultations for cough, phlegm, and wheeze in children living in a home where family members smoke compared with those not exposed to environmental tobacco smoke. To model these costs to provide the Territory of Hong Kong with estimates of potentially avoidable health care resource use. DESIGN: Cross sectional questionnaire survey. SUBJECTS AND SETTING: All children (10,615) in classes primary 3 to 6 (aged 8-13 years) attending 27 schools in two districts of Hong Kong in 1992 and their parents. MEASUREMENTS AND MAIN RESULTS: Doctor consultations during the previous three months for symptoms of either cough, phlegm or wheeze were higher in younger children, ranging from 22.9% in 8 year olds to 8.4% in those aged 12 or over. For those children living in homes with one, or more than one, smoker category (there were four categories of smokers: father, mother, siblings, others), the adjusted odds ratios (95% confidence intervals) for a doctor consultation for any of these symptoms were 1.15 (1.01, 1.31) and 1.38 (1.14, 1.67) respectively. Using US$15 as the minimum cost incurred per consultation, the expected direct cost per annum per child of doctor consultations was 14% higher for children living in a one smoker category home and 25% for two or more compared with exposure to no smokers in the home. Using these values on a territory wide basis, the annual avoidable direct cost associated with exposure to tobacco smoke in children from birth to 12 years of age ranged from US$338,042 to US$991,591. CONCLUSIONS: Exposure to environmental tobacco smoke not only provides a respiratory health risk for children but also an avoidable excess cost to the family's financial resources and health service providers.

Child↗
PubMed1998

Comparison between two districts of the effects of an air pollution intervention on bronchial responsiveness in primary school children in Hong Kong.

STUDY OBJECTIVE: This study examined the impact on children's respiratory health of a government air quality intervention that restricted the sulphur content of fuels to 0.5% from July 1990 onwards. DESIGN/SETTING/PARTICIPANTS: This study examined the changes, one and two years after the introduction of the intervention, in airway hyperreactivity of non-asthmatic and non-wheezing, primary 4, 5, and 6, school children aged 9-12 years living in a polluted district compared with those in a less polluted district. Bronchial hyperreactivity (BHR)(a 20% decrease in FEV1 provoked by a cumulative dose of histamine less than 7.8 mumol) and bronchial reactivity slope (BR slope) (percentage change in logarithmic scale in FEV1 per unit dose of histamine) were used to estimate responses to a histamine challenge. The between districts differences after the intervention were studied to assess the effectiveness of the intervention. MAIN RESULTS: In cohorts, comparing measurements made before the intervention and one year afterwards, both BHR and BR slope declined from 29% to 16% (p = 0.026) and from 48 to 39 (p = 0.075) respectively in the polluted district; and from 21% to 10% (p = 0.001) and 42 to 36 (p > 0.100) in the less polluted district. Comparing measurements made in 1991 (one year after intervention) with those in 1992 (two years after intervention), only the polluted district showed a significant decline from 28% to 12% (p = 0.016) and from 46 to 35 (p = 0.014), for BHR and BR slope respectively, with a greater decline in both responses (p = 0.018 and 0.073) than in the less polluted district. CONCLUSION: Bronchial hyperresponsiveness tests can be used to support the evaluation of an air quality intervention. The demonstrated reduction in bronchial hyperresponsiveness is an indication of the effectiveness of the intervention.

Air Pollutants↗
PubMed1998

Short-term single-blind fluvoxamine treatment of pathological gambling.

OBJECTIVE: The authors' goal was to assess the efficacy and tolerability of the selective serotonin reuptake inhibitor fluvoxamine in the treatment of pathological gambling. METHOD: Sixteen patients with pathological gambling entered an 8-week placebo lead-in phase, and 10 of these patients completed an 8-week single-blind fluvoxamine trial. RESULTS: Seven of the 10 patients who completed the fluvoxamine trial were judged treatment responders at the end of the study: 1) they had greater than 25% decreases in their gambling behavior scores on the pathological gambling modification of the Yale-Brown Obsessive Compulsive Scale, and 2) their clinician-rated Clinical Global Impression scores for gambling severity were very much improved or much improved. Fluvoxamine treatment resulted in gambling abstinence in seven of the 10 patients. CONCLUSIONS: Findings from this preliminary study suggest that fluvoxamine may be effective in reducing the urge to gamble. Randomized placebo-controlled and maintenance trials are required to confirm these findings and to determine whether improvement persists.

Adult↗
PubMed1998

Sudden death during jungle trekking: a case of heat stroke.

Heat stroke, which is also known as "sun stroke," is a medical emergency, and fatalities can occur unless it is diagnosed early and treated efficiently. Heat stroke may manifest quite suddenly, giving little time to differentiate it from extreme physical exhaustion in collapsed subjects. It is also known to lead to serious disseminated intravascular coagulation. Sudden death in a young female is presented who collapsed after trekking in a hilly, jungle area in Malaysia on a warm, humid day. She had joined a weight reduction programme a few weeks earlier. She was found collapsed and in a semiconscious state in the jungle by her groupmates and was taken to hospital. On admission she was unconscious, hyperpyrexic, with rapid, thready pulse and a low blood pressure. Biochemical studies revealed metabolic acidosis, elevated liver and cardiac enzymes and impairment of renal function. Her coagulation profile was found to be impaired and she started bleeding through the mouth and nostrils. She also developed watery diarrhoea and initially a septicaemic condition, including acute enteritis was suspected. Despite active treatment, her condition deteriorated and she died eight hours after admission. Autopsy confirmed a generalised bleeding tendency, with pulmonary, oesophageal and gastrointestinal mucosal haemorrhages. Flame-shaped subendocardial shock haemorrhages were seen in the interventricular septum on the left side of the heart. The findings support a diagnosis of heat stroke. Various aspects related to heat stroke, the autopsy diagnosis and its prevention are discussed.

Adult↗
PubMed1997

High dose rate brachytherapy for carcinoma of the oral tongue.

PURPOSE: The purpose of this study is to assess the feasibility of treating early-staged tongue cancer with high dose rate (HDR) remote afterloading technique. Furthermore, a new figure of merit, the Geometry Index (GI), is introduced to quantify the quality of the implants. METHODS AND MATERIALS: Between 1994 and 1995, eight patients with carcinoma of the oral tongue were treated solely with interstitial implant using the HDR remote afterloading technique. Five patients had T1 N0 disease and the remaining three had T2 N0 disease. Elective neck treatment was withheld. The male-to-female ratio was 1:1, and the mean age 60 years (range: 32-72 years). The median follow-up time was 26 months (range: 6-30 months). The afterloading catheters were positioned through the submandibular approach with the assistance of templates. Six patients had single planar implant and the remaining two had double planar implant. The median number of catheters inserted was 5 (range: 4-9). The median dose given was 60 Gy in 10 fractions over 6 days. The interfraction interval was 7 h. Mandibular and maxillary shields were inserted prior to treatment. Thomadsen et al. introduced the use of Implant Quality Index (QI). We introduce a new parameter, GI, which is defined as ratio of the QI of the nonoptimized executed implant to the corresponding QI value of the nonoptimized idealized implant. RESULTS: The mucositis lasted for 6 to 20 weeks (median: 10 weeks). There was no local failure up to a median follow-up of 26 months. Two patients developed ipsilateral neck node metastases at 2 and 4 months following implant, respectively. One patient had involvement at level II and the other failed at level I to III. Both patients were salvaged by neck node dissection and regionally remained in control. One patient with multiple nodal metastases and extracapsular spread developed biopsy-proven liver metastases and succumbed 6 months following implant. One patient treated with double planar implant developed Grade 3 necrosis of the soft tissue and bone. This complication is largely preventable now, as we have acquired more technical expertise. The mean GI values for the single and double planar implants were 0.88 (range: 0.84-0.91) and 0.8, respectively. This correlates with our practical experience that it is more difficult to maintain a good geometry as double planar implant is required. The GI gives a better view of the geometry of implant as it compares the nonoptimized QI of the executed implant with its ideal counterpart. The failure to achieve a high GI in double planar implants is presumed to relate to technical difficulties rather than variation in individual performance. CONCLUSION: Our preliminary experience in treating early-staged tongue cancer with the HDR remote afterloading technique is inspiring, as it gives a local control rate of 100% with acceptable morbidity. Further studies are eagerly awaited to delineate the optimum schedule for this modality of treatment. It is hoped that the GI values, which represents the skills of insertion, could be routinely reported so that treatment results between different centers could be compared in a more precise manner.

Adult↗