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.

Japanese Encephalitis Virus Transmitted Via Blood Transfusion, Hong Kong, China

Japanese encephalitis virus (JEV) is a mosquitoborne virus endemic to China and Southeast Asia that causes severe encephalitis in <1% of infected persons. Transmission of JEV via blood transfusion has not been reported. We report transmission of JEV via blood donation products from an asymptomatic viremic donor to 2 immunocompromised recipients. One recipient on high-dose immunosuppressive drugs received JEV-positive packed red blood cells after a double lung transplant; severe encephalitis and a poor clinical outcome resulted. JEV RNA was detected in serum, cerebrospinal fluid, and bronchoalveolar lavage fluid specimens. The second recipient had leukemia and received platelets after undergoing chemotherapy. This patient was asymptomatic; JEV infection was confirmed in this person by IgM seroconversion. This study illustrates that, consistent with other pathogenic flaviviruses, JEV can be transmitted via blood products. Targeted donor screening and pathogen reduction technologies could be used to prevent transfusion-transmitted JEV infection in highly JEV-endemic areas.

The challenge of patient empowerment in hand hygiene promotion in health care facilities in Hong Kong

Patient empowerment programs in hand hygiene were implemented in 2 extended-care hospitals. Of the 223 patients approached by the infection control nurses, 167 patients (74.9%) participated in the program. A positive response from the health care workers was reported in 70 (93.3%) of 75 patients who reminded health care workers to clean hands as part of the empowerment program. A significant increase in volume of alcohol-based handrub consumption was observed during the intervention period compared with baseline.

Aspirin desensitisation for Chinese patients with coronary artery disease

OBJECTIVE. To assess the efficacy and safety of aspirin desensitisation in Chinese patients with coronary artery disease. DESIGN. Case series. SETTING. A regional hospital in Hong Kong. PATIENTS. Chinese patients with coronary artery disease and a history of a hypersensitivity reaction to aspirin or non-steroidal anti-inflammatory drug, who underwent aspirin desensitisation between February 2008 and July 2012. RESULTS. There were 24 Chinese patients with coronary artery disease who were admitted to our unit for aspirin desensitisation during this period. The majority (79%) were clinical admissions for desensitisation; eight (33%) of them developed a hypersensitivity reaction during desensitisation. Half of the latter had only limited cutaneous reactions and were able to complete the desensitisation protocol and developed aspirin tolerance. Overall, 20 (83%) of the patients were successfully desensitised at the initial attempt. No serious adverse reactions occurred in the cohort. Twelve of the patients had significant coronary artery disease revealed by coronary angiography and received a percutaneous coronary intervention, nine of whom received drug-eluting stents while three received bare metal stents due to financial constraints. All 11 successfully desensitised patients received aspirin and clopidogrel as double antiplatelet therapy after percutaneous coronary intervention. The remaining patient had a bare metal stent implant due to failed aspirin desensitisation. CONCLUSION. Given the potentially different genetic basis of aspirin hypersensitivity in different ethnicities, recourse to desensitisation in the Chinese population has not previously been addressed. This study demonstrated that aspirin desensitisation using a rapid protocol can be performed effectively and safely in Chinese patients. Our results were comparable to those in other reported studies involving other ethnicities. Successful aspirin desensitisation permits patients to pursue long-term double antiplatelet therapy that includes aspirin after percutaneous coronary intervention, and thus allows the use of drug-eluting stents as a feasible option.

Reperfusion strategy for ST-segment elevation myocardial infarction: trend over a 10-year period

OBJECTIVES. To review the 10-year trend of reperfusion strategies in patients with ST-segment elevation myocardial infarction, and the adoption rate of percutaneous coronary interventions as opposed to thrombolytic therapy. Also to explore why some patients did not receive reperfusion therapy, and document changes in reperfusion strategies after the introduction of primary percutaneous coronary intervention programmes. DESIGN. Case series. SETTING. A regional hospital, Hong Kong. PATIENTS. All patients with ST-segment elevation myocardial infarction from January 2000 to December 2009. RESULTS. There were 1835 patients with ST-segment elevation myocardial infarction in that period, of which 1179 (64.3%) received reperfusion therapy (thrombolytic therapy, 46.0%; primary percutaneous coronary intervention, 17.5%; emergency coronary artery bypass graft, 0.7%). After introduction of the primary percutaneous coronary intervention programme, significantly more ST-segment elevation myocardial infarction cases underwent that particular intervention (1.6% in 2000 increasing to 30.6% in 2009), while the proportion receiving thrombolytic therapy declined (57.4% in 2000 decreasing to 35.0% in 2009). Seven reasons for no reperfusion therapy were identified. The commonest ones were delayed presentation (45.1%), succumbed before reperfusion (16.0%), multiple medical co-morbidities (15.2%), and contra-indication to thrombolytic therapy (14.8%). The proportion without reperfusion therapy due to a contra-indication to thrombolytic therapy declined (22.7% in 2000 decreasing to 4.9% to 2009), whilst an increasing proportion received primary percutaneous coronary interventions. CONCLUSIONS. Primary percutaneous coronary intervention is increasingly used as the reperfusion therapy in ST-segment elevation myocardial infarction and is replacing thrombolytic therapy, though the latter still remains a mainstay of therapy. A significant proportion of ST-segment elevation myocardial infarction cases received no reperfusion due to various reasons.

Primary percutaneous coronary intervention for ST elevation myocardial infarction: performance with focus on timeliness of treatment

OBJECTIVE

To review primary percutaneous coronary interventions performed for patients with ST elevation myocardial infarction with a focus on door-to-treatment time, especially after introduction of a new management programme in November 2003.

DESIGN

Retrospective study.

SETTING

Regional hospital, Hong Kong.

PATIENTS

All patients with ST elevation myocardial infarction who underwent primary percutaneous coronary intervention in our hospital from January 2002 to December 2007.

RESULTS

In all, 209 patients with ST elevation myocardial infarction had primary percutaneous coronary interventions between January 2002 and December 2007; 140 of them were admitted within office hours, 125 of whom came directly from Accident and Emergency Department. The mean door-to-balloon time of these patients was 115 minutes, and in 41% the time was less than 90 minutes (as recommended by the American College of Cardiology/American Heart Association guidelines). Since introduction of the new programme, the mean door-to-balloon time has diminished significantly, from 146 to 116 minutes (P=0.047). Delay in diagnosis (28%) and Cardiac Catheterization Laboratory being occupied (20%) were the two most common reasons for prolonged door-to-balloon times.

CONCLUSION

We achieved satisfactory performance in our primary percutaneous coronary intervention programme, providing timely reperfusion therapy for patients with ST elevation myocardial infarction. A well-organised and systematic clinical pathway is a prerequisite for a centre that provides a timely and effective primary percutaneous coronary intervention service for patients with ST elevation myocardial infarction. Better public education and greater awareness on the part of medical service providers are needed, so as to facilitate urgent revascularisation and improve outcomes in patients with ST elevation myocardial infarction.

Analyses of fluoroquinolones and Clostridium difficile-associated diarrhoea in tuberculosis patients

SETTING

Systematic studies of fluoroquinolones (FQs) and Clostridium difficile-associated diarrhoea (CDAD) are scarce among tuberculosis (TB) patients, in whom fluoroquinolones (FQs) are increasingly used.

OBJECTIVE

To evaluate the relationship between FQs and CDAD among TB patients.

DESIGN

Retrospective cohort and nested case-control analyses were conducted among 3319 hospital patients on anti-tuberculosis treatment from 1999 to 2005. Each case of CDAD was matched by three sex- and age-matched controls randomly selected from the rest of the cohort. Not every case was confirmed by C. difficile cytotoxins.

RESULTS

Among 38 cases studied, the incidence of CDAD, which was 28.2 (95%CI 20.3-38.3) per 100 000 patient-days overall, increased from 12.9 (95%CI 5.8-25.3) for patients aged <60 years to 26.6 (95%CI 15.5-42.8) for those aged between 60 and 79 years, and 66.9 (95%CI 39.8-106.1) for those aged >79 years. Univariate analysis showed a significant association between CDAD and age, FQs, non-FQ antibiotics, serum albumin level, duration of hospital stay and nasogastric feeding. Only duration of hospital stay and nasogastric feeding remained significant on multivariable analysis.

CONCLUSION

The risk of CDAD due to FQs among TB patients is probably modest after controlling for sex, age, non-FQ antibiotics, serum albumin level, duration of hospital stay and nasogastric feeding.

Non-operative management of small cell carcinoma of esophagus

Primary small cell carcinoma of the esophagus (SmCC) is an uncommon aggressive tumor characterized by early systemic dissemination and poor prognosis, regardless of the methods of treatment. The optimal treatment strategy remains uncertain. A retrospective study was conducted to review the results of non-operative treatment for patients with limited and metastatic esophageal SmCC. Between 1993 and 2003, 10 patients were diagnosed to have primary esophageal SmCC in our institution. Six of them had disseminated diseases, whereas the other four had limited disease upon diagnosis. All patients were managed non-operatively by either chemotherapy and/or radiotherapy. The overall median survival was 8 months (range, 2-62 months). The survival was 4-62 months for patients with limited disease, whereas it was 2-10 months for patients with disseminated disease at initial diagnosis. In summary, the current study demonstrated satisfactory palliation could be achieved with chemo-radiation for patients with limited disease; however, the ultimate role of primary chemo-radiation for esophageal SmCC must await results from randomized trials.

Relationship between glutathione S-transferase gene polymorphisms and enzyme activity in Hong Kong Chinese asthmatics

BACKGROUND

Asthma is a disease associated with oxidative stress. The glutathione S-transferases (GST) are a group of enzymes that protect cells from oxidative stress. Functional genetic polymorphisms of GST genes (GSTT1, GSTM1 and GSTP1) have previously been reported.

OBJECTIVE

To investigate the association of GST gene polymorphisms and its enzyme activity with the risk of asthma in Hong Kong Chinese adults.

METHODS

An age- and smoking status-matched case-control study was carried out on 315 patients with asthma and 315 healthy controls. Genotyping was carried out on genomic DNA using the PCR and/or restriction fragment length polymorphism (PCR-RFLP). Plasma GST activity was measured by fluorometric assay.

RESULTS

The distribution of various genotypes or alleles of the GSTT1, GSTM1 and GSTP1 was not significantly different between patients with asthma and healthy controls. The GSTM1 null genotype was found to be protective from the development of asthma in atopic subjects (odds ratios 0.55, 95% confidence interval 0.34-0.90; P=0.017). However, there was no association between GSTT1 and GSTM1 null genotypes and enzyme activity. GSTP1 codon 105 Val variants led to reduced plasma GST activity in healthy controls. Asthma patients had elevated plasma GST activity compared with healthy controls irrespective of their genotypes (P<0.001).

CONCLUSION

Our data suggest that among atopic subjects, the GSTM1 null genotype is associated with a decreased risk for asthma despite increased level of plasma GST activity in asthma, but it could not distinguish whether this increase is a potentially protective compensatory effect or a pathogenic factor.

Non-operative management of endoscopic iatrogenic haemobilia: case report and review of literature

Haemobilia denotes an abnormal communication between a vessel of the splanchnic circulation and the biliary system. Patients typically presents with the triad of abdominal pain, upper gastrointestinal haemorrhage, and jaundice. Common causes for haemobilia are iatrogenic causes secondary to hepatobiliary system instrumentation and trauma. Management of patients with haemodynamic significant haemobilia is aimed at stopping bleeding, maintaining continuous flow of biliary system, and cure of the underlying aetiology. Iatrogenic haemobilia after ERCP polyethylene biliary endoprosthesis placement is extremely uncommon. Herein we present a case of iatrogenic haemobilia triggered by biliary endoprosthesis placement and was successfully managed by non-operative treatment. The management algorithm for a rational approach to haemobilia is discussed.

Primary closure versus T-tube drainage after laparoscopic choledochotomy for common bile duct stones

BACKGROUND/AIMS

To demonstrate the safety and feasibility of primary closure of the common bile duct (CBD) after laparoscopic choledochotomy in patients with CBD stones. Traditionally, the CBD is closed with T-tube drainage after choledochotomy and removal of CBD stones. However, the insertion of a T-tube is not without complication and the patients have to carry it for several weeks before removal. In the laparoscopic era, surgery is performed with minimally invasive techniques in order to reduce the trauma inflicted on patients, hasten their recovery and hence reduce the hospital stay. T-tube insertion seems to negate these benefits and we believe that primary closure can be as safe as closure with T-tube drainage.

METHODOLOGY

This is a retrospective analysis of patients who underwent primary closure of the CBD after successful laparoscopic choledochotomy for ductal stones between January 2000 and December 2003. A concurrent control group of patients who underwent T-tube drainage was used for comparison.

RESULTS

Of the 64 patients that underwent laparoscopic exploration of the CBD, 24 (37%) underwent transcystic duct approach and 40 (63%) underwent choledochotomy. There were three open conversions (5%). Stone clearance was achieved in all patients with successful laparoscopic choledochotomy (100%). Of the 38 successful laparoscopic choledochotomies, 12 had primary closure of the CBD and 26 had closure with T-tube drainage. There was no mortality in both groups. One patient in the primary closure group suffered from paralytic ileus and small subhepatic collection which was treated conservatively. The median operative time (90 vs. 120 minutes, p=0.002) and postoperative stay (5 vs. 8.5 days, p=0.003) were shorter in the primary closure group when compared with the T-tube group.

CONCLUSIONS

Primary closure of the CBD is feasible and as safe as T-tube insertion after laparoscopic choledochotomy for stone disease.

Routine use of laparoscopic repair for perforated peptic ulcer

BACKGROUND

Laparoscopic repair of perforated peptic ulcer was reported in 1990 but has not gained wide acceptance. The aim of this study was to evaluate the safety and efficacy of laparoscopic repair for perforated peptic ulcer in routine clinical practice.

METHODS

This was a prospective analysis of 172 patients who underwent laparoscopic repair of a perforated peptic ulcer between July 1997 and June 2003.

RESULTS

One hundred and seventy-two patients of mean age 54 (range 14-93) years had perforated peptic ulcer diagnosed by laparoscopy. There were 172 duodenal ulcers, 22 prepyloric and 13 non-juxtapyloric gastric ulcers. One hundred and sixty-five patients underwent omental patch closure of perforations; there were six Pólya gastrectomies and one ulcerectomy. Thirty-seven patients (21.5 per cent) required conversion to laparotomy. The mean operating time was 64.8 (range 14-180) min. The median postoperative requirement for intramuscular pethidine was one dose. The median postoperative hospital stay was 6 days. Complications occurred in 28 patients (16.3 per cent) resulting in three reoperations. Six patients with intra-abdominal collections were managed by percutaneous drainage. Two patients who underwent conversion developed a wound infection. Fourteen patients (8.1 per cent) died, 11 of whom were American Society of Anesthesiologists grade III and IV.

CONCLUSION

Laparoscopic repair of perforated peptic ulcer is a safe emergency procedure in routine clinical practice for patients with perforated pyloroduodenal ulcer.

Laparoscopic exploration of common bile duct in difficult choledocholithiasis

BACKGROUND

This review investigated the role played by laparoscopic exploration of the common bile duct (LECBD) in the management of difficult choledocholithiasis.

METHODS

This retrospective study reviewed a prospective database of LECBD for difficult choledocholithiasis during the period 1995 to 2003.

RESULTS

Of the 97 LECBDs performed in the authors' center from 1995 to 2003, 25 were performed for difficult choledocholithiasis. Difficult choledocholithiasis was defined as failure of endoscopic stone retrieval for the following reasons: access and cannulation difficulty, the difficult nature of common bile duct (CBD) stones, and the presence of endoscopic retrograde cholangiopancreatography (ERCP)-related complications. There were seven unsuccessful cannulations because of previous gastrectomy (n = 5) and periampullary diverticulum (n = 2). Among the 18 patients with failed endoscopic extraction, there were 10 impacted stones, 2 incomplete stone clearances after multiple attempts, 2 type 2 Mirizzi syndromes, 1 proximal stent migration, 1 repeated post-ERCP pancreatitis, 1 situs inversus, and 1 stricture at the distal common bile duct. There were 14 male and 11 female patients with a mean age of 67.8 +/- 15 years. Initial presentations included cholangitis (n = 14, 56%), biliary colic (n = 3, 12%), jaundice/deranged liver function ( n = 5, 20%), cholecystitis (n = 2, 8%), and pancreatitis (n = 1, 4%). Regarding the approach for LECBD, there were 2 transcystic duct explorations and 23 choledochotomies. The mean operative time was 149.4 +/- 49.3 min, and there were three conversions (12%). The stone clearance rate was 100%, and no recurrence was detected during a mean follow-up period of 16.8 months. Five complications were encountered, which included bile leak (3 patients) and wound infection (2 patients). When the results were compared with the remaining 72 LECBDs for nondifficult stones during the same period, the complication rate, conversion rate, and rate of residual stones were similar despite a longer operation time (149.4 +/- 49.4 min vs 121.6 +/- 50.5 min).

CONCLUSION

When ERCP is impossible or stone retrieval is incomplete, LECBD is the solution to difficult CBD stones.

Chondroitinase ABC enhances axonal regrowth through Schwann cell-seeded guidance channels after spinal cord injury

Grafting of Schwann cell-seeded channels into hemisected adult rat thoracic spinal cords has been tested as a strategy to bridge the injured cord. Despite success in guiding axonal growth into the graft, regeneration across the distal graft-host interface into the host spinal cord was limited. We hypothesized that chondroitin sulfate (CS) glycoforms deposited at the gliotic front of the interface constitute a molecular barrier to axonal growth into the host cord. Because CS glycoforms deposited by purified astrocytes in vitro were removable by digestion with chondroitinase ABC, we attempted to achieve likewise by infusion of the enzyme to the host side of the interface. By 1 month post-treatment, significant numbers of regenerating axons crossed an interface that was subdued in macrophage/microglia reaction and decreased in CS-immunopositivity. The axons extended as far into the caudal cord as 5 mm, in contrast to nil in vehicle-infused controls. Fascicular organizations of axon-Schwann cell units within the regenerated tissue cable were better-preserved in enzyme-treated cords than in vehicle-infused controls. We conclude that CS glycoforms deposited during gliosis at the distal graft-host interface could be cleared by the in vivo action of chondroitinase ABC to improve prospects of axonal regeneration into the host spinal cord.

Smoking and tuberculosis in Hong Kong

OBJECTIVE

To study the relationship between smoking and tuberculosis in Hong Kong.

METHOD

Indirect sex and age adjustment was used to compare the prevalence of ever smokers between a sample of 851 patients from the 1996 tuberculosis notification registry and the general population. The clinical characteristics of smokers and non-smokers were compared by stratified univariate analysis and multiple logistic regression.

RESULTS

Tuberculosis patients were more likely to have smoked than population controls. The respective odds ratios for ever smoking between tuberculosis patients and population controls were 2.44 and 2.08 for males and females aged 16-64 (Mantel-Haenszel weighted OR = 2.40, P < 0.001), and 2.09 and 2.83 for males and females aged > or = 65 (Mantel-Haenszel weighted odds ratio = 2.19, P < 0.001). Male sex, age > or = 65, working at onset of illness, regular alcohol use, drug abuse and absence of contact history were associated with ever smokers (all P < 0.05). Ever smokers were more likely to have cough (OR 1.69), dyspnoea (OR 1.84), upper zone involvement (OR 1.67), cavity (OR 1.76), miliary lung involvement (OR 2.77), positive sputum culture (OR 1.43), but less isolated extrathoracic involvement (OR 0.31), even after controlling for the confounding background variables (all P < 0.05).

CONCLUSION

There was a consistent association between smoking and tuberculosis. More aggressive lung involvement was also found among ever smokers.

Laparoscopic cholecystectomy versus open cholecystectomy in elderly patients with acute cholecystitis: retrospective study

OBJECTIVE

To study the safety and efficacy of laparoscopic cholecystectomy for acute cholecystitis in elderly patients by comparing the results with open cholecystectomy.

DESIGN

Retrospective study.

SETTING

Regional hospital, Hong Kong.

SUBJECTS AND METHODS

Patients aged 75 years or older undergoing laparoscopic cholecystectomy for acute cholecystitis between January 1994 and December 1999 were selected from the database. The comparison group comprised patients from the same age-group who underwent open cholecystectomy for acute cholecystitis during the same period.

MAIN OUTCOME MEASURES

Operating time, hospital stay, morbidity, and mortality. RESULTS. Thirty-one patients underwent laparoscopic surgery and 42 had open surgery. The demographic data and co-morbidities were comparable between the two groups. The postoperative hospital stay was significantly shorter for patients undergoing laparoscopy (P=0.03). The overall morbidity rate was significantly lower for patients undergoing laparoscopy (P<0.05). There was, however, no statistical significant difference in the mortality rate. There was no major bile duct injury for patients in either group.

CONCLUSION

Laparoscopic cholecystectomy is a safe procedure for acute cholecystitis in elderly patients, resulting in fewer complications and shorter hospital stay than open cholecystectomy.

Chronic necrotizing pulmonary aspergillosis. A report of 9 cases with analysis of clinical picture, risk factors and treatment for outcome correlation

Nine patients with chronic necrotizing pulmonary aspergillosis (CNPA) were analyzed retrospectively. Eight cases had been treated with itraconazole. Four patients had received intravenous amphotericin B (AMB), three sequentially with itraconazole and one as monotherapy. Three patients died after 1, 2 and 24 weeks of therapy. Six responded to therapy and survived 3 to 58 months after treatment. Only the total number of risk factors was found to be statistically significant in relation to a fatal outcome. The mean number of risk factors was 5.33 for fatal cases compared to 2.83 for treatment responders. The presence of five or more risk factors and two individual risk factors, hypoalbuminemia less than 27 g/L and history of dual pulmonary mycobacterioses, were 100% predictive of mortality in our patients. The overall clinical picture of fatal CNPA cases resembles closely that of acute invasive pulmonary aspergillosis in severely immunocompromised subjects.

Comparison of MB/BacT system and agar proportion method in drug susceptibility testing of Mycobacterium tuberculosis

The drug susceptibilities of 105 isolates/strains of Mycobacterium tuberculosis (101 clinical isolates and four control strains from the American Type Culture Collection) were assessed by the MB/BacT system and conventional agar proportion method. The agreement rates between the two methods were 99.0% for streptomycin, 95.2% for isoniazid and 100% for rifampin. The mean times to detection for drug-resistant isolates were 4.7 days (range: 2.5-13.7 days) using the MB/BacT system and 14.8 days (range: 14-21 days) using the agar proportion method. For drug-susceptible isolates, the times to detection were 10.8 days (mean) and 21 days respectively. Thus, these data have demonstrated that the automated, non-radiometric MB/BacT system is an efficient, accurate and reliable method for assessing drug susceptibilities of M. tuberculosis compared with the conventional agar proportion method.

Laparoscopic cholecystectomy and exploration of common bile duct in a patient with situs inversus

Situs inversus is a rare anomaly with a genetic predisposition. We report a patient with situs inversus, cholelithiasis, and choledocholithiasis who was treated successfully with laparoscopic cholecystectomy and laparoscopic exploration of the common bile duct. We believe this to be the first such case reported in the literature.

Serum pharmacokinetics of antimycobacterial drugs in patients with multidrug-resistant tuberculosis during therapy

Serum samples of 13 patients with multidrug-resistant tuberculosis were taken 0, 1, 2, 4, 8 h after administration of antimycobacterial drugs for assay of levels in order to gain further insight into their basic pharmacokinetics. The drugs assessed were amikacin, kanamycin, ofloxacin, levofloxacin, para-aminosalicylic acid, prothionamide, cycloserine, pyrazinamide and ethambutol. Techniques used for assay were reversephase high-performance liquid chromatography, gas liquid chromatography and fluorescent polarization immunoassay. The results from 12 patients were evaluated. These provided new pharmacokinetic data on high-dose levofloxacin, cycloserine and prothionamide given once daily, and could be useful in guiding the scheduling of drugs. The data obtained might also lead to insights into the development of therapeutic drug monitoring in multidrug-resistant tuberculosis.

Outcomes of patients with multidrug-resistant pulmonary tuberculosis treated with ofloxacin/levofloxacin-containing regimens

OBJECTIVE

To analyze outcomes of patients with multidrug-resistant tuberculosis (MDR-TB) treated with ofloxacin/levofloxacin-containing regimens.

MATERIALS AND METHODS

From February 1990 through June 1997, 63 MDR-TB patients (with bacillary resistance to at least isoniazid and rifampin in vitro) were analyzed retrospectively. Twenty-two patients (34.9%) had had no previous antituberculosis chemotherapy. Each patient received either ofloxacin (53) or levofloxacin (10) even though 13 patients had bacilli resistant to ofloxacin in vitro. The other accompanying drugs mainly included aminoglycosides, cycloserine, ethionamide/prothionamide, and pyrazinamide. Sputum smear and culture examinations for acid-fast bacilli (AFB) were performed monthly for the initial 6 months and then at 2- to 3-month intervals until the end of treatment. Comparison was made between clinical successes and failures using univariate and multiple logistic regression analyses for the following variables: age, sex, presence of cavitation, extent of disease, sputum smear positivity, in vitro resistance to ofloxacin, in vitro resistance to streptomycin and/or ethambutol, treatment adherence, and the number of drugs per regimen.

RESULTS

Fifty-one patients (81.0%) were cured, nine patients (14.3%) failed, and three patients (4.7%) died. For the entire group, the mean duration of treatment was 14.0 months, and the mean number of drugs was 4.7. Mean durations of chemotherapy in successful and failed patients were 14.5 and 14.2 months, respectively. Mean time for sputum smear and culture conversions were 1.7 and 2.1 months, respectively. Only cavitation, resistance to ofloxacin, and poor adherence were found to be variables independently associated with adverse outcomes (p < 0.05; odds ratios = 15.9, 13.5, 12.8, respectively). Negative sputum cultures after 2 and 3 months of therapy were 100% predictive of cure. Positive sputum cultures after 2 and 3 months were 52.3% and 84.6% predictive of failure, respectively. One patient (2.1%) relapsed after apparent cure. Twenty-five patients experienced adverse drug reactions, but only 12 of them needed drug modifications.

CONCLUSION

Most MDR-TB patients can be treated effectively with ofloxacin/levofloxacin-containing regimens. Presence of cavitation, resistance to ofloxacin in vitro, and poor adherence to therapy portend treatment failure. Monitoring monthly sputum culture for AFB in the initial months of chemotherapy helps predict clinical outcomes.

Fibreoptic bronchoscopy in the diagnosis of lung cancer

A total of 562 patients with lung cancer was evaluated by fibreoptic bronchoscopy (FOB) by three bronchoscopic diagnostic procedures: biopsy, bronchial brushing and bronchial washing. Endoscopically visible tumours (EV) were detected in 264, while 257 had endoscopically nonvisible tumours > or = 2 cm in diameter and FOB was done without fluoroscopy because of limited availability (ENV). Forty-one had small (< 2 cm), endoscopically nonvisible tumours with FOB performed under uniplanar fluoroscopy (ENV + F). The overall diagnostic yield rates of FOB were 98.1%, 61.5% and 58.5% for the EV, ENV and ENV + F cases, respectively. Reviewing the differential yield rates of the three diagnostic techniques and comparing them with the results of previous studies led to the following conclusions. (1) Combinations of biopsy with brushing and biopsy with washing can diagnose more than 95% of all fibreoptic bronchoscopy positive cases with endoscopically visible tumours. Performing either of these combinations may be more cost-effective than doing all three techniques routinely. (2) For cases with endoscopically nonvisible tumours, performance of all three diagnostic techniques is recommended, especially when fibreoptic bronchoscopy is performed without fluoroscopic guidance, as washing and brushing seem to compensate for a lower yield of the biopsy. (3) For tumours < 2 cm in diameter, knowledge on the diagnostic efficacy of fibreoptic bronchoscopy was limited owing to the small size of previous studies. The yield of 58.5% for fibreoptic bronchoscopy in these patients with performance of all three diagnostic procedures was comparatively high. It could be further increased to 75.6% if supplemented by percutaneous needle biopsy when fibreoptic bronchoscopy turned out to be nondiagnostic. If available, the use of transbronchial needle aspiration may also increase the overall diagnostic yield of fibreoptic bronchoscopy in these cases.

Is inhaled corticosteroid useful as adjunctive management in tuberculous pyrexia?

Systemic corticosteroid is currently the standard adjunctive therapy for tuberculous pyrexia. A preliminary prospective open study to examine the efficacy of inhaled budesonide at a dose of 2,400 micrograms daily in the management of this condition was performed. Out of nine non-HIV infected patients with tuberculous pyrexia studied, four patients succeeded to achieve defervescence at a mean of 3.25 days (range = 2 to 5 days), while the rest of the patients failed to do so within 7 days. None of the patients had unwanted side effects of systemic corticosteroid and patients' acceptance of such therapy was high. The potential usefulness of inhaled corticosteroid in some patients with tuberculous pyrexia might warrant further evaluation.

Heparan sulphates upregulate regeneration of transected sciatic nerves of adult guinea-pigs

The increased content of soluble glycosaminoglycan-containing forms in sciatic nerves during recovery from crush injury [Shum & Chau (1996) J. Neurosci. Res., 46, 465] suggests that the glycosaminoglycans modulate the environment for post-traumatic tissue remodelling and axonal regrowth. To test this, defined amounts of soluble heparan sulphates from bovine kidney or guinea-pig nerve were introduced into the regenerating environment via silicone conduits that bridged 8-mm gaps of transected sciatic nerves of adult guinea-pigs. Controls were bridged using the phosphate-buffered saline (PBS) vehicle or a chondroition sulphate preparation from whale cartilage. After timed periods of recovery, the animals were assessed for electromyographic signals at the target gastrocnemius muscle to determine the conduction velocity across the bridged nerve. Sections of the bridge were also histologically examined for nerve fibres. Transected sciatic nerves bridged with heparan sulphates or chondroitin sulphate showed earlier stimulated myelination of axons (week 5-6) than PBS-bridged nerves (week 9). Initial electromyographic indication of reconnection with the target was at week 9 post-transection. In the course of 20 weeks, transected sections of the bridge indicated similar numbers of unmyelinated axons irrespective of bridge material, but distinctly higher numbers of myelinated axons in heparan sulphate-bridged nerves than either PBS- or chondroitin sulphate-bridged nerves. At the end of the same period, heparan sulphate-bridged nerves resumed normal conduction velocities, but both PBS- and chondroitin sulphate-bridged nerves remained at 50% of that of the intact contralateral nerves. These results are the first to demonstrate that supplementation of soluble heparan sulphate to the fluid regenerative neural environment can restore functional, axonal reconnection of the severed nerve with the target muscle.

Future directions in the development of new antitubercular drugs. Where do we go from here?

The global resurgence of tuberculosis and rampant drug resistance have rekindled the need for and interest in the development of new antitubercular drugs. Delineation of the possible drug targets furnished by the various mycobacterial cell components might result in rational approaches to the development of such agents. In the future, molecular genetics might help both in the bioengineering and rapid screening of the activity of new compound. Collaboration is anticipated between the pharmaceutical industry and academic institutions in these areas.

Changes in glycosaminoglycans during regeneration of post-crush sciatic nerves of adult guinea pigs

The glycosaminoglycans of sciatic nerves recovering from crush-injury were studied in adult guinea pigs and compared with those of non-injured mature neural tissues. The glycosaminoglycans were recovered from the 1,900 g supernatant and pellet of the tissue homogenates and assayed for hexuronate contents and susceptibilities to hyaluronidase, chondroitinase ABC, and nitrous acid. In the normal brain and central nerve tracts, the glycosaminoglycans were distributed both in the supernatant and pellet fractions; the brain showed a predominance of chondroitin sulphates but the tracts showed a predominance of heparan sulphates. Twice as much glycosaminoglycans were found in normal sciatic nerves, only in the pellet fraction and with heparan sulphate predominant. In the 2 weeks post-crush, progressive increase in hexuronate was observed, due mainly to additional chondroitin sulphate forms in the supernatant; the pellet fraction in the same period was however similar to the untreated controls in relative abundance of glycosaminoglycan classes and hexuronate content. At 4 weeks post-crush, although the total hexuronate returned to the control level, a significant proportion of glycosaminoglycans remained in the supernatant fraction. Evidence is thus provided for the need to modulate the glycosaminoglycan expression pattern in adult neural tissue to allow post-traumatic tissue remodelling and axonal regrowth.

New antimycobacterial agents

The resurgence of tuberculosis and the increased prevalence of atypical mycobacterial infections in immunocompromised subjects have prompted the quest for novel antimycobacterial agents. Fluoroquinolones, such as ofloxacin and ciprofloxacin, might be promising agents for treatment of tuberculosis especially multidrug-resistant tuberculosis (MDR-TB) and infections caused by Mycobacterium fortuitum. Clarithromycin, an important member of the macrolides, has been shown to have activity against some infections due to Mycobacterium avium-intracellulare, M. fortuitum and Mycobacterium chelonae. Rifabutin, being a rifamycin, has been found to be efficacious in treatment of drug-susceptible tuberculosis, although its place in MDR-TB is less certain. Rifabutin in combination with other drugs might constitute active regimens for treatment of disseminated M. avium-intracellulare infections. When used alone, it can be an active prophylactic agent against such infection. Imipenem, a carbapenem, might provide promising treatment for some M. fortuitum and M. chelonae infections. The place of beta-lactam-beta-lactamase inhibitor combinations in the treatment of MDR-TB is uncertain. Clofazimine and aminosidine being riminophenazine and aminoglycoside, respectively, might merit further evaluation as potentially useful agents for treatment of MDR-TB and M. avium-intracellulare infections. However, much broader evaluation of all these agents in clinical settings is still definitely required.

Low-dose methotrexate in the management of Chinese patients with steroid-dependent asthma

Nine Chinese patients with severe asthma who were dependent on a systemic oral steroid for control were given oral methotrexate at a dose of 7.5 mg on alternate days for two weeks, followed by 15 mg once weekly. Only six patients were evaluable; they had received methotrexate for 6 to 24 months. All six patients could have reduction of daily oral prednisolone dosage by 5-15 mg (mean: 10.4 mg). Only four patients, however, had > or = 15% improvement of their best peak expiratory flow rates compared with baseline levels, though all six patients had symptomatic improvement. These beneficial effects were, however, transient and persisted only during methotrexate therapy. Four patients had liver enzyme changes and discontinuation of therapy was required in one patient. One patient also had infective spondylitis secondary to Salmonella bacteremia. Thus low-dose oral methotrexate may be useful in selected patients with severe steroid-dependent asthma with careful monitoring for response and drug toxicity.

Drug-resistant tuberculosis in the 1990s

There has been an upsurge of tuberculosis in many parts of the world in the past decade. The high rates of drug-resistant tuberculosis currently reported in many countries are alarming. The most catastrophic phenomenon is the emergence of multidrug-resistant strains of Mycobacterium tuberculosis. These organisms have caused epidemic outbreaks in nosocomial and health-care settings in the USA and some European countries. In addition to immigration, poverty, alcoholism and intravenous substance abuse, human immunodeficiency virus (HIV) infection has also had a significant impact on the prevalence of drug resistance, since amongst these patient groups a common factor giving rise to drug resistance is noncompliance. Rapid drug susceptibility tests are needed, and effective chemotherapy regimens with newly developed drugs in combination with traditional second-line antituberculosis agents for established multidrug-resistant tuberculosis are urgently being sought. There is also a quest for other novel modalities of therapy. Measures should be actively adopted to prevent the development of drug resistance. Well formulated short-course chemotherapy as initial treatment and ensurance of compliance are the most important components. The organization of a national tuberculosis control programme with a sound and adequately functioning infrastructure remains the most effective strategy to combat the resurgence of tuberculosis and to curtail drug resistance.

Ciprofloxacin-induced renal dysfunction in patients with mycobacterial lung infections

3 patients with mycobacterial lung infections, one due to Mycobacterium avium-intracellulare and 2 due to M. tuberculosis, developed ciprofloxacin-induced acute renal dysfunction while receiving the drug together with other antimycobacterial agents. These episodes took place 8-10 days after commencement of therapy and recovered spontaneously after cessation of all antimycobacterial drugs for 2-8 weeks. No recurrence was noted when patients were restarted on regimens that did not contain ciprofloxacin.