Kenneth W. Tsang

Risk Factors for Acquisition of Levofloxacin-Resistant Streptococcus pneumoniae: A Case-Control Study

A case-control study was conducted to identify the risk factors associated with levofloxacin-resistant Streptococcus pneumoniae (LRSP) colonization or infection. Twenty-seven case patients (patients with LRSP) were compared with 54 controls (patients with levofloxacin-susceptible S. pneumoniae). Risk factors that were significantly associated with LRSP colonization or infection, according to univariate analysis, included an older age (median age, 75 years for case patients versus 72.5 years for controls), residence in a nursing home (odds ratio [OR], 7.2), history of recent (OR, 4.6) and multiple (OR, 4.4) hospitalizations, prior exposure to fluoroquinolones (OR, 10.6) and beta-lactams (OR, 8.6), presence of chronic obstructive pulmonary disease (COPD; OR, 5.9), and nosocomial origin of the bacteria (OR, 5.7). Multivariate analysis showed that presence of COPD (OR, 10.3), nosocomial origin of the bacteria (OR, 16.2), residence in a nursing home (OR, 7.4), and exposure to fluoroquinolones (OR, 10.7) were independently associated with LRSP colonization or infection. Thus, a distinct group of patients with COPD is the reservoir of LRSP.

Helicobacter pylori and extra-digestive diseases

Helicobacter pylori is a recently rediscovered Gram‐negative bacteria that causes peptic ulcer disease, gastric lymphoma and gastric carcinoma. Helicobacter pylori achieves its pathogenetic role by triggering an intense leucocyte infiltration of the gastric submucosa which is mediated by proinflammatory cytokines. This pathogenetic mechanism is common to many other diseases and, therefore, Helicobacter pylori seroprevalence has also been investigated in other diseases. It is now known that H. pylori seropositivity is associated with an increasing number of cardiovascular, respiratory, extra‐gastroduodenal digestive, neurological, skin, autoimmune, growth and miscellaneous disorders. Although the precise role for H. pylori is unknown in these diseases, it is of tremendous interest to most clinicians and scientists as H. pylori is amenable to eradication therapy using simple and reliable drug regimens. The conditions associated with H. pylori seropositivity are highlighted in this concise article.

Clinical profiles of Chinese patients with diffuse panbronchiolitis

BACKGROUND Diffuse panbronchiolitis (DPB), characterised by progressive sinobronchial sepsis, is well characterised in Japanese subjects but not in other ethnic groups. The experience with DPB in seven Chinese patients is described and the clinical profiles compared with those of Japanese subjects. METHODS Seven Chinese patients (three women; mean (SD) age 48(18.6) years, all never smokers) who attended a teaching hospital centre and fulfilled the diagnostic criteria for DPB were assessed prospectively for clinical, radiological, lung function, microbiological, and other “characteristic” laboratory parameters. RESULTS Lung function assessment showed a typical obstructive pattern (n = 5) and air trapping (n = 7). Typical bronchiolar infiltration by lymphocytes and plasma cells and accumulation of foamy macrophages in the intraluminal tissue were detected in open lung biopsy specimens (n = 2). Chest radiographs and high resolution computed tomographic scans revealed hyperinflation, diffuse nodules, bronchial thickening and dilatation, peripheral hypoattenuation, and bronchiolectasis. Radiological improvement, manifest as a reduction in nodular density and bronchial thickening, and persistence of other abnormalities such as air trapping were not accurately depicted by the classical Nakata or Akira classifications. The other “characteristic” features such as HLA-B54, IgG subclass deficiency, raised CD4/CD8 T lymphocyte ratio, cold haemagglutinaemia, raised IgA, IgG, and rheumatoid factor were not present. Treatment with erythromycin led to excellent responses in symptoms, lung function indices, and the radiological picture. A review of the non-Japanese cases in the literature reveals that this absence of typical “additional features” in DPB might also be applicable to non-Japanese patients. CONCLUSIONS We report the only series of non-Japanese Mongoloid patients with well characterised DPB who had uncharacteristic investigation profiles. This experience should help other clinicians in the investigation and management of DPB in non-Japanese patients.

Perception of benefits and costs during SARS outbreak: An 18-month prospective study

In this study, the authors examined perceived benefits and costs of the outbreak of severe acute respiratory syndrome (SARS). Mixed accounts of benefits and costs, rather than exclusive accounts of only benefits or costs, were proposed to be characterized by nondefensiveness and enduring changes in psychosocial resources. Participants were 70 SARS recoverers, 59 family members of SARS recoverers, and 172 healthy adults residing in Hong Kong--a SARS-affected region. Results show that participants giving an exclusive account of benefits had higher levels of defensiveness than those giving a mixed account and those giving an exclusive account of costs. Only the perceived impact of benefits given in mixed accounts were related to future accruements in personal and social resources over an 18-month period.

Pulmonary sequelae of treatment for breast cancer: A prospective study

PURPOSE To prospectively study the effects of loco-regional radiotherapy in women with breast cancer. METHODS AND MATERIALS Thirty consecutive patients with breast resection underwent clinical, lung function, radiographic, and thoracic high-resolution computed tomography evaluation before and at 1, 3, 6, and 12 months after adjuvant radiotherapy. Chemotherapy was also administered to 15 patients. RESULTS Nineteen patients reported mild respiratory symptoms at 1 month, which resolved completely at 6 months after radiotherapy. Opacities were present on 80% of chest radiographs and in all patients on high-resolution computed tomography by 3 months. These opacities became compact and persisted on high-resolution computed tomography at 12 months. Lung function indices, including FEV1, FVC, TLC, and DLCO, progressively declined after radiotherapy, and was irreversible at 12 months (p < 0.05). Patients who received chemotherapy did not have significantly different lung function indices compared with their counterparts at all time points (p > 0.05). CONCLUSIONS Our results have shown that adjuvant loco-regional radiotherapy, a common practice in breast cancer treatment, is associated with irreversible reduction in lung function parameters. These changes are accompanied by radiological evidence of persistent lung injury. Further studies should be performed to evaluate the incidence and long-term pulmonary sequelae of current treatment for breast cancer.

Manganese superoxide dismutase and catalase genetic polymorphisms, activity levels, and lung cancer risk in Chinese in Hong Kong

Introduction: Antioxidants play an important role in counteracting the effects of potential carcinogens. We investigated the risk of lung cancer development with respect to manganese superoxide dismutase (MnSOD) and catalase genetic polymorphisms and their association with erythrocyte antioxidant activities. Patients and Methods: This was a case-control study involving patients with confirmed lung cancer and age-matched healthy controls. Genotyping of MnSOD and catalase in DNA extracted from peripheral white cells was performed by polymerase chain reaction-based restriction fragment length polymorphism. Erythrocyte superoxide dismutase and catalase activities were measured spectrophotometrically using chemical kinetic reactions. Results: We recruited 240 patients with lung cancer (63% male, aged 55.6 ± 11.9 years, 58% adenocarcinoma, 85% clinical stage III or IV) and 240 age-matched healthy controls. The frequencies of the Val allele of MnSOD gene and the C allele of catalase gene were common (>86% and 90%, respectively), with similar distribution, in both patients with lung cancer and controls. The homozygous variant genotypes of MnSOD and catalase were not associated with increased lung cancer risk. The erythrocyte SOD and catalase activity was significantly lower among all patients with lung cancer as a whole compared with controls, irrespective of genotypes. However, patients with adenocarcinoma and non-adenocarcinoma showed differences in SOD and catalase activity among different genotypes in comparison with controls. Conclusion: The common Val16Ala MnSOD polymorphism and C-T substitution in the promoter region of the catalase gene do not confer increased or reduced risk of lung cancer in Chinese in Hong Kong.

Clinical challenges in managing bronchiectasis.

Bronchiectasis is a common disease in the Asia–Pacific and affected patients suffer from chronic sputum production and recurrent exacerbations. Bronchiectasis is largely idiopathic although there is diverse aetiology. The pathogenesis of bronchiectasis comprises infective, inflammatory and emzymetic elements. These interact to perpetuate continued airway damage in bronchiectasis leading to progressive airway and lung damages. Treatment of bronchiectasis is unsatisfactory and there are only very few trials. Existing data suggest some efficacy of inhaled corticosteroid therapy, which has been shown recently to clinical and anti‐inflammatory properties in bronchiectasis. Immunomodulating agent such as low‐dose macrolides have also been shown to have some efficacy although more data are needed to advocate their long‐term usage. Antibiotic therapy is complex in bronchiectasis and includes short‐term empirical treatment for acute exacerbation, and consideration of long‐term maintenance of oral, nebulized and i.v. therapy. This long‐neglected illness should receive more research attention in order that we can have better understanding of its aetiology, pathogenesis and treatment.

Immediate and sustained psychological impact of an emerging infectious disease outbreak on health care workers.

Objective: To assess the immediate and sustained psychological health of health care workers who were at high risk of exposure during the severe acute respiratory syndrome (SARS) outbreak. Methods: At the peak of the 2003 SARS outbreak, we assessed health care workers in 2 acute care Hong Kong general hospitals with the Perceived Stress Scale (PSS-10). One year later, we reassessed these health care workers with the PSS-10, the 21-Item Depression and Anxiety Scale (DASS-21), and the Impact of Events Scale-Revised (IES-R). We recruited high-risk health care workers who practised respiratory medicine and compared them with nonrespiratory medicine workers, who formed the low-risk health care worker control group. Results: In 2003, high-risk health care workers had elevated stress levels (PSS-10 score = 17.0) that were not significantly different from levels in low-risk health care worker control subjects (PSS-10 score = 15.9). More high-risk health care workers reported fatigue, poor sleep, worry about health, and fear of social contact, despite their confidence in infection-control measures. By 2004, however, stress levels in the high-risk group were not only higher (PSS-10 score = 18.6) but also significantly higher than scores among low-risk health care worker control subjects (PSS-10 score = 14.8, P < 0.05). In 2004, the perceived stress levels in the high-risk group were associated with higher depression, anxiety, and posttraumatic stress scores (P < 0.001). Posttraumatic stress scores were a partial mediator of the relation between the high risk of exposure to SARS and higher perceived stress. Conclusions: Health care workers who were at high risk of contracting SARS appear not only to have chronic stress but also higher levels of depression and anxiety. Front-line staff could benefit from stress management as part of preparation for future outbreaks.

Psychological effects of the SARS outbreak in Hong Kong on high-risk health care workers

Objective: To quantify stress and the psychological impact of severe acute respiratory syndrome (SARS) on high-risk health care workers (HCWs). Method: We evaluated 271 HCWs from SARS units and 342 healthy control subjects, using the Perceived Stress Scale (PSS) to assess stress levels and a structured list of putative psychological effects of SARS to assess its psychological effects. Healthy control subjects were balanced for age, sex, education, parenthood, living circumstances, and lack of health care experience. Results: Stress levels were raised in both groups (PSS = 18) but were not relatively increased in the HCWs. HCWs reported significantly more positive (94%, n = 256) and more negative psychological effects (89%, n = 241) from SARS than did control subjects. HCWs declared confidence in infection-control measures. Conclusions: In HCWs, adaptive responses to stress and the positive effects of infection control training may be protective in future outbreaks. Elevated stress in the population may be an important indicator of future psychiatric morbidity.

Stress and psychological impact on SARS patients during the outbreak.

Objective: To examine stress and psychological impact in severe acute respiratory syndrome (SARS) patients during the 2003 outbreak. SARS is a novel, highly infectious pneumonia, and its psychological impact is still unclear. Method: At the peak of the outbreak, SARS patients (n = 79) and healthy control subjects (n = 145) completed the Perceived Stress Scale (PSS) and documented a range of psychological responses. Groups were balanced for age, sex, education, and living circumstances. Results: Stress was significantly higher in SARS patients than in healthy control subjects. Stress correlated significantly with negative psychological effects. Of SARS patients, 39% (n = 30) were infected health care workers; these individuals reported significantly more fatigue and worries about health than did other patients. Of patients, 25% (n = 20) requested psychological follow-up. Conclusions: General stress and negative psychological effects are increased in SARS patients, particularly among infected health care workers. This may increase the risk of mood and stress-related disorders. Functional impairment is apparent in the postrecovery phase.