Delayed diagnosis of tuberculosis: risk factors and effect on mortality among older adults in Hong Kong.

OBJECTIVE: To assess the risk factors and effects of delayed diagnosis on tuberculosis (TB) mortality in Hong Kong. METHODS: All consecutive patients with TB notified in 2010 were tracked through their clinical records for treatment outcome until 2012. All TB cases notified or confirmed after death were identified for a mortality survey on the timing and causes of death. RESULTS: Of 5092 TB cases notified, 1061 (20.9%) died within 2 years of notification; 211 (4.1%) patients died before notification, 683 (13.4%) died within the first year, and 167 (3.3%) died within the second year after notification. Among the 211 cases with TB notified after death, only 30 were certified to have died from TB. However, 52 (24.6%) died from unspecified pneumonia/sepsis possibly related to pulmonary TB. If these cases are counted, the total TB-related deaths increases from 191 to 243. In 82 (33.7%) of these, TB was notified after death. Over 60% of cases in which TB diagnosed after death involved patients aged ≥80 years and a similar proportion had an advance care directive against resuscitation or investigation. Independent factors for TB notified after death included female sex, living in an old age home, drug abuse, malignancy other than lung cancer, sputum TB smear negative, sputum TB culture positive, and chest X-ray not done. CONCLUSIONS: High mortality was observed among patients with TB aged ≥80 years. Increased vigilance is warranted to avoid delayed diagnosis and reduce the transmission risk, especially among elderly patients with co-morbidities living in old age homes.

Determinants of chronic obstructive pulmonary disease in Chinese patients in Hong Kong.

BACKGROUND: The prevalence of chronic obstructive pulmonary disease (COPD) is rising in many parts of the world. This is a study of risk factors for COPD in Chinese patients in Hong Kong. DESIGN: Case-control study matched by sex and age (+/-5 years). METHODS: A total of 289 consecutive patients with COPD were recruited from out-patient clinics while healthy controls were recruited from two sources: random population and community centres for senior citizens. All patients and controls underwent a questionnaire-based interview and spirometry. RESULTS: The mean ages of COPD patients and controls were 71.1 +/- 9.4 and 67.5 +/- 9.3 years, respectively. The male to female ratio of COPD patients was 5 to 1. Smoking was found to be the most important determinant for COPD, followed by poor education and low body mass index adjusted for confounders. A dose-dependent relationship was found between the risk of COPD and pack-years smoked. Place of birth, exposure to environmental tobacco smoke and a history of asthma and tuberculosis were not associated with increased risk of COPD. CONCLUSION: Despite a progressive reduction in prevalence, smoking remains the most important predictor of COPD in Hong Kong. Greater anti-smoking efforts are warranted.

Use of fluorescein as a ground water tracer in brackish water aquifers.

A drift and pumpback experiment was conducted in a brackish water sandfill. The sandfill was reclaimed from the sea in the eastern part of Singapore and contains sands with low organic and clay/silt contents. The high salinity in the ground water precludes the use of chloride and bromide as tracers in such an environment, and a field experiment was conducted to assess the viability of using fluorescein as a tracer in brackish water aquifers. Nitrate was used as a second tracer to serve as a check. Initial laboratory studies showed that fluorescence was unaffected over the range of electrical conductivity and pH of the ground water. Results from the field experiment show that fluorescein appears to behave conservatively.

IV radionuclide total-body arteriography: a new noninvasive whole-body screening procedure--a case report.

Recently the authors introduced a new technique of intravenous (IV) radionuclide total-body arteriography. The major arterial system, multiple organs of the whole body, and cardiac function can be evaluated with one small IV injection in the arm. After analyzing more than 1000 cases, they have found that many pathologies can be detected and/or confirmed in this procedure. This new technique may be used as a general whole-body screening test for those patients at high risk for disease.

Reevaluation of plain radiographic findings in the diagnosis of aortic rupture: the role of inspiration and positioning on mediastinal width.

Despite the advent of newer imaging modalities, conventional radiography and clinical examination remain the primary screening method in evaluation of the mediastinum following blunt thoracic trauma. Mediastinal width (MW) is generally considered an important finding in assessing for aortic rupture. The degree of inspiration and patient positioning clearly affects MW, but is largely ignored in the literature. This study investigates the mediastinal widths of normal volunteers with differing degrees of inspiration and positioning, and compares them to radiographs of patients with known aortic ruptures. Mediastinal widths were obtained from chest radiographs of 16 patients with known aortic rupture, and from 50 volunteers using AP-inspiratory-supine, AP-expiratory-supine, and PA-inspiratory-upright technique. Upper 95% confidence limits were obtained for normals. A statistically significant difference in MW of normals was found between inspiratory-supine, expiratory-supine, and upright-inspiratory techniques. Compared to the same degree of inspiration in normals, 12 of 16 patients with aortic rupture had a MW above the upper 95% confidence limits. It is concluded that mediastinal width in normals is significantly affected by the degree of inspiration and positioning. When comparing mediastinal widths for normals and ruptures, there was a significant difference in MW for most degrees of inspiration. As depth of inspiration increased, differences between MW in controls and rupture patients increased. We conclude that patient positioning and degree of inspiration are important factors in assessing the mediastinum, and every effort should thus be made to obtain an upright-inspiratory film if clinically feasible prior to declaring a mediastinum as abnormal.

Intravenous radionuclide total body arteriography: a new technique.

We have developed a technique using a blood pool agent Tc-99m labeled red blood cells and a detector head set moving at a high speed to obtain total body arterial and blood pool images with only a single intravenous injection. Previously with an intravenous radiotracer injection, only regional arterial images could be obtained. Now, with this simple, non-invasive technique, we can evaluate the major arterial system, organs, and soft tissues in the whole body, as well as cardiac function. On reviewing 500 cases, more than 90% of the first-pass arterial phase images clearly demonstrated the aorta, ilio-femoral arteries, and, to a lesser extent, the more distal arteries in the lower extremities. The second-pass blood pool images revealed the anatomical and morphological status of the solid organs, as well as perfusion changes in various organs and soft tissues.

Management and prevention of spontaneous pneumothorax using pleurodesis in Hong Kong.

BACKGROUND: The practice of pleurodesis for the management and prevention of spontaneous pneumothorax (SP) is uncertain. DESIGN: A retrospective multicentre analysis of patients admitted to 12 hospitals in Hong Kong with SP in 2004 and who subsequently underwent pleurodesis for the same episode. RESULTS: Pleurodesis was performed in 394 episodes. Initial medical chemical pleurodesis was performed for 258 (65.5%) patients ('initial medical group'), while 136 (34.5%) underwent initial surgical pleurodesis ('initial surgical group'). Secondary spontaneous pneumothorax (SSP; 237 episodes, 60.2%) was the most common indication for pleurodesis; it was also performed after a first episode of primary spontaneous pneumothorax (PSP) in 22 episodes (5.6%). Tetracycline derivatives (172 episodes, 66.7%) were the most popular sclerosing agents in the initial medical group. Those in the initial medical group were older and were more likely to be males, have SSP, chronic obstructive pulmonary disease and a history of past pleurodesis (P < 0.05) compared to the initial surgical group. Compared to the tetracycline group, more patients who initially received talc slurry had the procedure performed by surgeons, had larger (≥2 cm) pneumothorax or required suction during initial drainage (P < 0.05). CONCLUSIONS: Despite the availability of international guidelines, there is considerable variation in pleurodesis for SP.

Minocycline and talc slurry pleurodesis for patients with secondary spontaneous pneumothorax.

SETTING: Few studies have evaluated the sclerosing efficacy of minocycline, and none have specifically compared its sclerosing efficacy and safety profiles with talc slurry in secondary spontaneous pneumothorax (SSP). DESIGN: A retrospective analysis was conducted in patients with SSP who underwent chemical pleurodesis from January to December 2004 with minocycline or talc slurry in 12 public hospitals of Hong Kong. RESULT: There were 121 episodes of minocycline pleurodesis and 64 episodes of talc slurry pleurodesis. Immediate procedural failure were similar in the minocycline and talc slurry groups (21.5% vs. 28.1%, P = 0.31). Presence of interstitial lung disease, ≥ 2 previous episodes of pneumothorax, requiring mechanical ventilation during pleurodesis and persistent air leak before pleurodesis were independently associated with procedural failure. Pain was experienced in respectively 44.6% and 37.5% of the minocycline and the talc slurry groups. Pain was more common in patients receiving high doses of talc (≥ 5 g; P = 0.03). Respiratory distress was found in respectively 1.7% and 1.6% of the minocycline and talc slurry groups. CONCLUSION: Minocycline and talc slurry had comparable sclerosing efficacy in SSP, with immediate success rates of >70%. Pain was the most common adverse effect and respiratory distress was uncommon. Both appeared to be effective and safe for chemical pleurodesis in SSP.

Coronavirus as a possible cause of severe acute respiratory syndrome.

BACKGROUND: An outbreak of severe acute respiratory syndrome (SARS) has been reported in Hong Kong. We investigated the viral cause and clinical presentation among 50 patients. METHODS: We analysed case notes and microbiological findings for 50 patients with SARS, representing more than five separate epidemiologically linked transmission clusters. We defined the clinical presentation and risk factors associated with severe disease and investigated the causal agents by chest radiography and laboratory testing of nasopharyngeal aspirates and sera samples. We compared the laboratory findings with those submitted for microbiological investigation of other diseases from patients whose identity was masked. FINDINGS: Patients' age ranged from 23 to 74 years. Fever, chills, myalgia, and cough were the most frequent complaints. When compared with chest radiographic changes, respiratory symptoms and auscultatory findings were disproportionally mild. Patients who were household contacts of other infected people and had older age, lymphopenia, and liver dysfunction were associated with severe disease. A virus belonging to the family Coronaviridae was isolated from two patients. By use of serological and reverse-transcriptase PCR specific for this virus, 45 of 50 patients with SARS, but no controls, had evidence of infection with this virus. INTERPRETATION: A coronavirus was isolated from patients with SARS that might be the primary agent associated with this disease. Serological and molecular tests specific for the virus permitted a definitive laboratory diagnosis to be made and allowed further investigation to define whether other cofactors play a part in disease progression.