Yield of bronchoscopy for the diagnosis of tuberculosis in patients with human immunodeficiency virus infection

Endobronchial Tuberculosis in an HIV-positive Case

INTRODUCTION

Tuberculosis is an opportunist infection that is fatal and most frequently seen in HIV-positive patients due to immunosuppression. Endobronchial lesions can portray symptoms in different ways. Endobronchial Tuberculosis is one of these lesions.

CASE REPORT

An HIV-positive, untreated 26-year-old patient with fever, cough, and dyspnea consulted our clinic. In the chest X-ray taken, effusion on the right side and non-homogeneous density increase in the middle and upper lobes, bilaterally more prominent on the right side, were observed. Therefore, the patient underwent bronchoscopy because the CT (computerized tomography) showed mediastinal lymphadenopathy (LAP) and an endobronchial lesion in the left main bronchus. During bronchoscopy, a vegetative endobronchial lesion that causes obstruction in the left main bronchus was monitored. With the help of Pathology and PCR results, endobronchial tuberculosis was diagnosed.

CONCLUSION

Even if Acid-alcohol-resistant Bacillus (ARB) is detected negative in patients who stop responding to antimicrobial treatment and are being monitored under radiological scanning, a distinctive diagnosis of endobronchial tuberculosis should be kept in mind while performing bronchoscopy.

The Role of Post-Bronchoscopy Sputum Examination in Screening for Active Tuberculosis

Early diagnosis is a fundamental component of global tuberculosis control. The objective of this study was to evaluate the diagnostic yield of post-bronchoscopy sputum (PBS) testing as part of a tuberculosis diagnostic work-up. All new residents in the State of Qatar undergo a tuberculosis (TB) screening program. Those with abnormal chest radiology, negative sputum acid-fast bacilli (AFB) smears, and nucleic acid amplification testing (NAAT) for M. tuberculosis, undergo an additional bronchoscopic evaluation for TB. We prospectively enrolled individuals who were going to undergo bronchoscopy to provide two PBS samples for AFB smears and mycobacterial cultures between 18 September 2018 and 12 March 2021. A total of 495 individuals, with a median age of 31 years, were included. The majority of the patients were males (329, 66.5%). The most frequent country of origin was India (131, 26.5%) followed by the Philippines (123, 24.8%). The addition of PBS to bronchoalveolar lavage (BAL) testing allowed microbiological confirmation of tuberculosis in an additional 13 patients (3.9%), resulting in improved sensitivity (from 77.9% to 81.9%), negative predictive value (from 69.2% to 73.2%), and negative likelihood ratio (from 0.22 to 0.18). Where resources are available, the incorporation of routine PBS examination as part of tuberculosis diagnostic work-up can enhance the diagnostic yield.

Deep-Learning-Aided Detection of Mycobacteria in Pathology Specimens Increases the Sensitivity in Early Diagnosis of Pulmonary Tuberculosis Compared with Bacteriology Tests

The histopathological diagnosis of mycobacterial infection may be improved by a comprehensive analysis using artificial intelligence. Two autopsy cases of pulmonary tuberculosis, and forty biopsy cases of undetected acid-fast bacilli (AFB) were used to train AI (convolutional neural network), and construct an AI to support AFB detection. Forty-two patients underwent bronchoscopy, and were evaluated using AI-supported pathology to detect AFB. The AI-supported pathology diagnosis was compared with bacteriology diagnosis from bronchial lavage fluid and the final definitive diagnosis of mycobacteriosis. Among the 16 patients with mycobacteriosis, bacteriology was positive in 9 patients (56%). Two patients (13%) were positive for AFB without AI assistance, whereas AI-supported pathology identified eleven positive patients (69%). When limited to tuberculosis, AI-supported pathology had significantly higher sensitivity compared with bacteriology (86% vs. 29%, p = 0.046). Seven patients diagnosed with mycobacteriosis had no consolidation or cavitary shadows in computed tomography; the sensitivity of bacteriology and AI-supported pathology was 29% and 86%, respectively (p = 0.046). The specificity of AI-supported pathology was 100% in this study. AI-supported pathology may be more sensitive than bacteriological tests for detecting AFB in samples collected via bronchoscopy.

Bronchoscopic sampling techniques in the era of technological bronchoscopy

Flexible bronchoscopy is a key diagnostic and therapeutic tool. New endoscopes and technologically advanced navigational modalities have been recently introduced on the market and in clinical practice, mainly for the diagnosis of mediastinal lymph adenopathies and peripheral lung nodules. Bronchoscopic sampling tools have not changed significantly in the last three decades, with the sole exception of cryobiopsy. We carried out a non-systematic, narrative literature review aimed at summarizing the scientific evidence on the main indications/contraindications, diagnostic yield, and safety of the available bronchoscopic sampling techniques. Performance of bronchoalveolar lavage, bronchial washing, brushing, forceps biopsy, cryobiopsy and needle aspiration techniques are described, focusing on indications and diagnostic accuracy in the work-up of endobronchial lesions, peripheral pulmonary abnormalities, interstitial lung diseases, and/or hilar-mediastinal lymph adenopathies. Main factors affecting the diagnostic yield and the navigational methods are evaluated. Preliminary data on the utility of the newest sampling techniques (i.e., new needles, triple cytology needle brush, core biopsy system, and cautery-assisted transbronchial forceps biopsy) are shown. TAKE HOME MESSAGE: A deep knowledge of bronchoscopic sampling techniques is crucial in the era of technological bronchoscopy for an optimal management of respiratory diseases.

Comparison of sputum induction and bronchoscopy in diagnosis of sputum smear-negative pulmonary tuberculosis: a systemic review and meta-analysis

Background

Pulmonary tuberculosis is one of the most common infectious diseases worldwide. Patients with suspected pulmonary tuberculosis with negative smear are recommended to undergo further tests including sputum induction and bronchoscopy. Our study is aimed to compare sputum induction and bronchoscopic specimens in the diagnosis of sputum smear-negative pulmonary tuberculosis.

Method

PubMed, Web of Science, Cochrane Library and Embase were searched for eligible studies. The pooled sensitivities (SEN), specificities (SPE), positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR) and 95% confidence intervals (CI) were constructed, and the areas under the curves (AUCs) were calculated.

Results

Five studies with a total number of 586 cases were included. For mycobacterial culture, the SEN and SPE of sputum induction were 0.72(95% CI, 0.66–0.77) and 1.00(95%CI, 0.99–1.000) respectively, whereas the SEN and SPE of bronchoscopy were 0.70(95%CI, 0.64–0.75) and 1.00(95%CI, 0.99–1.00) respectively. Sputum induction had a similar AUC (0.9564, SE = 0.0749) with bronchoscopy (0.8618, SE = 0.1652) (P = 0.602). For specimen of acid-fast bacilli smear, the SEN and SPE of sputum induction were 0.35(95% CI, 0.29–0.42) and 0.99(95% CI, 0.96–1.00) respectively, whereas the SEN and SPE of bronchoscopy were 0.38(95% CI, 0.32–0.45) and 0.99(95% CI, 0.96–1.00) respectively. There is no statistically significant difference in the AUC for sputum induction (0.6016) compared with bronchoscopy (0.8163) (P = 0.792).

Conclusions

For the diagnosis of sputum smear-negative pulmonary tuberculosis, the diagnosis yield of sputum induction and bronchoscopy is similar.

The cursed duet today: Tuberculosis and HIV-coinfection

The tuberculosis (TB) and HIV syndemic continues to rage and are a major public health concern worldwide. This deadly association raises complexity and represent a significant barrier towards TB elimination. TB continues to be the leading cause of death amongst HIV-infected people. This paper reports the challenges that lay ahead and outlines some of the current and future strategies that may be able to address this co-epidemic efficiently. Improved diagnostics, cheaper and more effective drugs, shorter treatment regimens for both drug-sensitive and drug-resistant TB are discussed. Also, special topics on drug interactions, TB-IRIS and TB relapse are also described. Notwithstanding the defeats and meagre investments, diagnosis and management of the two diseases have seen significant and unexpected improvements of late. On the HIV side, expansion of ART coverage, development of new updated guidelines aimed at the universal treatment of those infected, and the increasing availability of newer, more efficacious and less toxic drugs are an essential element to controlling the two epidemics. On the TB side, diagnosis of MDR-TB is becoming easier and faster thanks to the new PCR-based technologies, new anti-TB drugs active against both sensitive and resistant strains (i.e. bedaquiline and delamanid) have been developed and a few more are in the pipeline, new regimens (cheaper, shorter and/or more effective) have been introduced (such as the "Bangladesh regimen") or are being tested for MDR-TB and drug-sensitive-TB. However, still more resources will be required to implement an integrated approach, install new diagnostic tests, and develop simpler and shorter treatment regimens.

Official American Thoracic Society/Infectious Diseases Society of America/Centers for Disease Control and Prevention Clinical Practice Guidelines: Diagnosis of Tuberculosis in Adults and Children

BACKGROUND

Individuals infected with Mycobacterium tuberculosis (Mtb) may develop symptoms and signs of disease (tuberculosis disease) or may have no clinical evidence of disease (latent tuberculosis infection [LTBI]). Tuberculosis disease is a leading cause of infectious disease morbidity and mortality worldwide, yet many questions related to its diagnosis remain.

METHODS

A task force supported by the American Thoracic Society, Centers for Disease Control and Prevention, and Infectious Diseases Society of America searched, selected, and synthesized relevant evidence. The evidence was then used as the basis for recommendations about the diagnosis of tuberculosis disease and LTBI in adults and children. The recommendations were formulated, written, and graded using the Grading, Recommendations, Assessment, Development and Evaluation (GRADE) approach.

RESULTS

Twenty-three evidence-based recommendations about diagnostic testing for latent tuberculosis infection, pulmonary tuberculosis, and extrapulmonary tuberculosis are provided. Six of the recommendations are strong, whereas the remaining 17 are conditional.

CONCLUSIONS

These guidelines are not intended to impose a standard of care. They provide the basis for rational decisions in the diagnosis of tuberculosis in the context of the existing evidence. No guidelines can take into account all of the often compelling unique individual clinical circumstances.

HIV-1 and the Mycobacterium tuberculosis granuloma: A systematic review and meta-analysis

Infection with HIV-1 greatly increases the risk of active tuberculosis (TB). Although hypotheses suggest HIV-1 disrupts Mycobacterium tuberculosis (Mtb) granuloma function, few studies have examined this directly. The objective of this study was to determine what evidence exists about the effect HIV-1 co-infection has upon Mtb granulomas. A systematic search of PubMed, Web of Science, and Medline up to 20 March 2015 was conducted, to identify studies comparing Mtb-infected tissue from HIV-1 infected and uninfected persons, or HIV-1 infected persons with stratified peripheral CD4 T cell (pCD4) counts. We summarized findings that focused on how HIV-1 changes granuloma formation, bacterial presence, cellular composition, and cytokine production. Nineteen studies with a combined sample size of 899 persons were included. Although studies frequently were limited by variable or inadequately described definitions of outcomes and analytical methods, HIV-1 was found to be associated with increased bacillary load within Mtb-infected tissue. Reductions in pCD4 counts within co-infected persons associated with both poorer granuloma formation and higher bacterial load. The high degree of heterogeneity among studies combined with experimental limitations made it difficult to conclusively support previously published and prevalent hypotheses about HIV-1/Mtb co-infection granulomas. To elucidate the validity of these hypotheses we have described areas that can be improved in future studies in order to clarify the influence HIV-1 co-infection has upon the Mtb granuloma.

Diagnostic yield of post-bronchoscopy sputum smear in pulmonary tuberculosis

BACKGROUND

The early definitive diagnosis of pulmonary tuberculosis (TB) is important for control of the disease in the community. We performed this study to evaluate the additional gain of post-bronchoscopy sputum in the diagnosis of pulmonary TB.

METHODS

Bronchoscopy and bronchoalveolar lavage were performed for 126 patients suspected of pulmonary TB who either had 3 negative sputum smears for acid-fast bacilli or could not expectorate. After bronchoscopy the patients were asked to give sputum samples for 3 consecutive days. All of the obtained specimens were investigated for Mycobacterium tuberculosis by smear and culture.

RESULTS

Pulmonary TB was confirmed in 56 patients. Among all confirmed cases, the sensitivity of bronchoalveolar lavage smear was 57.1% (32 of 56), sensitivity of post-bronchoscopy smear was 76.7% (43 of 56), and the yield of a combination of the 2 methods was 83.9% (47 of 56). Results of post-bronchoscopy sputum smears were not significantly related to sex, age, human immunodeficiency virus (HIV) infection, presence of cavitary lesions on chest X-ray, or the ability to expectorate before bronchoscopy (p > 0.05).

CONCLUSION

Evaluation of post-bronchoscopy sputum smears is helpful for earlier diagnosis of pulmonary TB and is an inexpensive and accessible assay.

Post-bronchoscopy sputum: improving the diagnostic yield in smear negative pulmonary TB

INTRODUCTION

Patients with suspected active Pulmonary Tuberculosis (PTB) who are Acid-Fast Bacilli (AFB) smear negative or non-productive of sputum may undergo bronchoalveolar lavage. However, post-bronchoscopy sputum (PBS) sampling is not routine. The aim of this study was to establish the potential diagnostic value of PBS sampling.

METHODS

A retrospective study of patients attending a London University hospital with microbiologically confirmed PTB between January 2004 and December 2010. Patients who were AFB smear negative or non-productive of sputum were eligible if sputum sampling was performed within 7 days of bronchoscopy.

RESULTS

Over the study period, 236 patients had microbiologically confirmed smear negative PTB of which 57 patients were eligible for the study. 15 patients (26.3%) were infected with HIV. 19 patients (33.3%) converted to AFB sputum smear positivity post-bronchoscopy and 5 patients (8.8%) were exclusively AFB sputum smear positive on PBS microscopy. Mycobacterium tuberculosis was cultured from the PBS of 43 patients (75.4%) and of these, 4 (7.0%) were exclusively PBS culture positive.

CONCLUSION

PBS analysis can provide a simple method of rapidly diagnosing pulmonary tuberculosis. In this cohort, M. tuberculosis culture yield was increased by 7% through PBS sampling. This study has important infection control implications with nearly one third of patients becoming more infectious after bronchoscopy.

Bronchoscopy in suspected pulmonary TB with negative induced-sputum smear and MTD(®) Gen-probe testing

INTRODUCTION

In our institution, patients with suspected pulmonary TB undergo multiple induced-sputum sampling for microscopy, culture and nucleic acid amplification (NAA) with the MTD(®) Gen-probe assay. Those with negative induced-sputum results still suspected with TB are then referred for bronchoscopy. We sought to determine the diagnostic yield of bronchoscopy in these patients with negative initial induced-sputum results both via smear and NAA testing.

METHODS

We identified 30 consecutive cases of suspected pulmonary TB between 2001 and 2007, who had undergone a diagnostic bronchoscopy after negative results on induced-sputum smears and the MTD(®) Gen-probe on at least 2 samples.

RESULTS

The cohort (M = 20 & F = 10) had a median age of 37 (range 16-85 yrs); were predominantly foreign born (27/30); HIV-negative (29/30) individuals with strongly positive TST's (mean 18 + 5 mm). Induced-sputum cultures were negative for M-TB in all patients after a full 60-day incubation period. BAL was culture positive for M-TB in 3/30 cases (10%) with 2 strains being pan-sensitive and the third being INH resistant. BAL microscopy with acid-fast smear (n = 30) and BAL Gen-probe (n = 23) were negative in all cases. A third of the patients (9/27, 33%) with negative bronchoscopy results were treated for culture negative TB. Treatment for latent TB was initiated in 5/27 (18%) individuals whereas 13/27 (48%) received no further treatment.

CONCLUSION

Bronchoscopy provided diagnostic confirmation of pulmonary TB in 10% of subjects at least 2 negative induced-sputum samples by smear microscopy and NAA testing.

Study of bronchoalveolar lavage in clinically and radiologically suspected cases of pulmonary tuberculosis

CONTEXT

About 30 to 50 % of pulmonary tuberculosis patients have sputum report negative for acid fast bacilli or present with no expectoration. A lot of research is going on to find methods to establish early and accurate diagnosis of pulmonary tuberculosis (PTB) as institutions of early treatment can have significant effects on morbidity and mortality of patients and also the development of MDR-TB. Samples other than sputum play an important role in the diagnosis of disease in such patients.

AIMS

To assess the significance of bronchoalveolar lavage samples and fiberoptic bronchoscopy (FOB) in the early diagnosis of occult sputum smear negative pulmonary tuberculosis.

SETTINGS AND DESIGN

Study was conducted in a tertiary care hospital. FOB was performed in patients with three consecutive sputum smear negative acid fast bacilli to obtain bronchoalveolar lavage (BAL) samples. Written informed consent was obtained from these patients.

MATERIALS AND METHODS

BAL samples were subjected to Z-N staining and culture on L-J slopes for acid fast bacilli. Sputum samples from the same patients were also cultured.

RESULTS

BAL samples were positive in 82.2% of sputum smear negative samples. Culture positivity of BAL samples was 90.9% as compared to sputum culture positivity which was 26.4%. Overall diagnosis could be established in 86.6% of patients with the help of fiber optic bronchoscopy.

CONCLUSIONS

BAL samples are very useful in early sputum smear negative pulmonary tuberculosis and FOB can play an important role in diagnosis of lower respiratory tract infections with minimal complications in hands of an expert.

Comparison of acid-fast stain and culture for Mycobacterium tuberculosis in pre- and post-bronchoscopy sputum and bronchoalveolar lavage in HIV-infected patients with atypical chest X-ray in Ethiopia

BACKGROUND:

Smear-negative tuberculosis occurs more frequently in human immunodeficiency virus (HIV)-infected patients than in non-HIV-infected patients. Besides, there are substantial numbers of patients who cannot produce sputum, making the diagnosis of pulmonary tuberculosis (PTB) difficult.

AIMS:

To evaluate the relative yield of pre- and post-bronchoscopy sputum and bronchoalveolar lavage (BAL) in ‘sputum smear’-negative, HIV-positive patients.

SETTINGS:

A tertiary care referral hospital in Addis Ababa.

MATERIALS AND METHODS:

Acid-fast stain (AFS) using the concentration technique was done on 85 pre-bronchoscopy sputum and 120 BAL samples. Direct AFS was done on all BAL and 117 post-bronchoscopy sputum samples. Culture for Mycobacterium tuberculosis (MTB) was done for all sputa and BAL.

RESULTS:

MTB was isolated from 26 (21.7%), 23 (19.7%) and 13 (15.3%) of BAL, post- and pre-bronchoscopy sputum cultures respectively. AFS on pre-bronchoscopy sputum using concentration technique and direct AFS on BAL together detected 11 (41%) of the 27 culture-positive cases. In patients who could produce sputum, the sensitivity of pre-bronchoscopy sputum culture (13/85, 15.3%) was comparable to BAL (12/85, 14%) and post-bronchoscopy sputum (12/85, 14%). In patients who could not produce sputum, however, both BAL (12/35, 40%) and post-bronchoscopy sputum (12/32, 31.4%) detected significantly more patients than those who could produce sputum (P=0.002, P=0.028 respectively).

CONCLUSION:

In HIV-infected patients, AFS by concentration method on pre-bronchoscopy sputum and direct AFS on BAL in patients who cannot produce sputum are the preferred methods of making a rapid diagnosis. BAL culture seems to add little value in patients who can produce sputum; therefore, bronchoscopy should be deferred under such circumstances.

Diagnostic accuracy of in-house PCR for pulmonary tuberculosis in smear-positive patients: meta-analysis and metaregression

In-house PCR (hPCR) could speed differential diagnosis between tuberculosis (TB) and nontuberculous mycobacterial disease in patients with positive smears and pulmonary infiltrates, but its reported accuracy fluctuates across studies. We conducted a systematic review and meta-analysis of hPCR sensitivity and specificity for smear-positive TB diagnosis, using culture as the reference standard. After searching English language studies in MEDLINE and EMBASE, we estimated cumulative accuracy by means of summary receiver operating characteristic analysis. The possible influence of hPCR procedures and study methodological features on accuracy was explored by univariate metaregression, followed by multivariate adjustment of items selected as significant. Thirty-five articles (1991 to 2006) met the inclusion criteria. The pooled estimates of the diagnostic odds ratio, sensitivity, and specificity (random-effect model) were, respectively, 60 (confidence interval [CI], 29 to 123), 0.96 (CI, 0.95 to 0.97), and 0.81 (CI, 0.78 to 0.84), but significant variations (mainly in specificity) limit their clinical applicability. The quality of the reference test, the detection method, and real-time PCR use explained some of the observed heterogeneity. Probably due to the limited study power of our meta-analysis and to the wide differences in both laboratory techniques and methodological quality, only real-time PCR also displayed a positive impact on accuracy in the multivariate model. Currently, hPCR can be confidently used to exclude TB in smear-positive patients, but its low specificity could lead to erroneous initiation of therapy, isolation, and contact investigation. As the inclusion of samples from treated patients could have artificially reduced specificity, future studies should report mycobacterial-culture results for each TB and non-TB sample analyzed.

Current evidence on diagnostic accuracy of commercially based nucleic acid amplification tests for the diagnosis of pulmonary tuberculosis

BACKGROUND

Even though commercial nucleic acid amplification tests (NAATs) have become the most frequently used molecular tests for laboratory diagnosis of pulmonary tuberculosis (TB), published studies report variable estimates of their diagnostic accuracy. We analysed the accuracy of commercial NAATs for the diagnosis of pulmonary TB in smear positive and smear negative respiratory samples using culture as a reference standard.

METHODS

English language studies reporting data sufficient for calculating sensitivity and specificity of commercial NAATs on smear positive and/or smear negative respiratory samples were included. Meta-regression was used to analyse associations with reference test quality, the prevalence of TB, sample and test type. Predictive values for different levels of pre-test probability were quantified using Bayes' approach.

RESULTS

Sixty three journal articles published between 1995 and 2004 met the inclusion criteria. Pooled sensitivity and specificity were 0.96 and 0.85 among smear positive samples and 0.66 and 0.98 among smear negative samples. The number of culture media used as reference test, the inclusion of bronchial samples, and the TB prevalence were found to influence the reported accuracy. The test type had no effect on the diagnostic odds ratio but seemed to be correlated with sensitivity or specificity, probably via a threshold effect.

CONCLUSIONS

Commercial NAATs can be confidently used to exclude TB in patients with smear positive samples in which environmental mycobacteria infection is suspected and to confirm TB in a proportion of smear negative cases. The methodological characteristics of primary studies have a considerable effect on the reported diagnostic accuracy.

The diagnosis of tuberculosis

Diagnostic testing for tuberculosis has remained unchanged for nearly a century, but newer technologies hold the promise of a true revolution in tuberculosis diagnostics. New tests may well supplant the tuberculin skin test in diagnosing latent tuberculosis infection in much of the world. Tests such as the nucleic acid amplification assays allow more rapid and accurate diagnosing of pulmonary and extrapulmonary tuberculosis. The appropriate and affordable use of any of these tests depends on the setting in which they are employed.

Tuberculosis prevention and control in long-term-care facilities for older adults

In the United States, older adults comprise 22% of cases of tuberculous disease but only 12% of the population. Most cases of tuberculosis (TB) occur in community dwellers, but attack rates are highest among frail residents of long-term-care facilities. The detection and treatment of latent TB infection and TB disease can pose special challenges in older adults. Rapid recognition of possible disease, diagnosis, and implementation of airborne precautions are essential to prevent spread. It is the intent of this evidence-based guideline to assist healthcare providers in the prevention and control of TB, specifically in skilled nursing facilities for the elderly.

Tuberculosis and HIV disease: two decades of a dual epidemic

The HIV epidemic is currently in its third decade without any sign of abating. Tuberculosis (TB) is responsible for a third of all AIDS deaths, 99% of which occur in developing countries. The two epidemics fuel each other, together making up the leading infectious causes of mortality worldwide. Tuberculosis-HIV coinfection presents special diagnostic and therapeutic challenges and constitutes an immense burden on the health care systems of heavily infected countries. Despite major gains that have been made in the past two decades, important questions still remain. To cope with the challenge of TB-HIV coinfection, further research in the design of diagnostic tests for tuberculosis, detection of drug resistant Mycobacterium tuberculosis strains in HIV-positive people, as well as development of more effective therapeutic agents and vaccines are urgently needed. It has become evident that this dual epidemic will persist unless comprehensive measures are instituted through the provision of sufficient funding in addition to expanding and strengthening current control strategies adopted by governments and international organizations.

Urban Tuberculosis: The New Face of an Old Problem

Tuberculosis (TB) persists as a worldwide health crisis. Nearly one third of the world's population is infected with TB and it remains a critical public health issue. In the past two decades, international efforts have focused on improving identification of those infected with TB as well as supporting molecular microbiologists in developing better diagnostic techniques. Furthermore, implementation of programs such as directly observed therapy have assisted more patients in receiving and completing therapy. This review aims to identify some of the more relevant findings in the field of TB over the past few years with a special emphasis on TB in urban communities.

Culturing bronchial washings obtained during bronchoscopy fails to add diagnostic utility to culturing the bronchoalveolar lavage fluid alone

A retrospective analysis was performed to determine whether cultures of bronchial washings (BW) obtained during bronchoscopy added to the diagnostic efficiency of cultures of bronchoalveolar lavage fluid (BAL) alone. Results of BW and BAL cultures submitted from 268 patients over a 7-month period were compared. The isolation of an organism from the BW but not from the BAL occurred in only 17.4% of cases. Moreover, the vast majority of those organisms consisted of yeasts or molds of questionable clinical significance that did not prompt a change in antimicrobial therapy. Culturing the BAL specimen alone would have resulted in an efficiency of 97.0% (95% confidence interval 94.2-98.7%) for the isolation of clinically relevant pathogens identified from bronchoscopic specimens. These results suggest that the submission of BW obtained during the BAL procedure for culture evaluation not only fails to add diagnostic value, but may also result in unnecessary laboratory evaluations and provide misleading information to clinicians.

The role of fibre-optic bronchoscopy in solid organ, transplant patients with pulmonary infections

Organ transplantation is currently the standard therapy for patients with end-stage organ dysfunction. The immunosuppression caused by this therapy increases the rate of infection, particularly in the lungs. Early diagnosis is extremely important and fibre-optic bronchoscopy is a helpful tool in reaching diagnosis. Knowing the timing of various pathogens following transplantation, and the radiological picture as well as the prophylactic regimen, is helpful when specific pathogens are suspected. Bronchoscopy with bronchoalveolar lavage and transbronchial biopsies are particularly helpful in diagnosis of bacterial cytomegalovirus (CMV) and pneumocytosis carinii pneumocytosis, and is considered a safe procedure. Open lung biopsy is reserved for those who have negative bronchoscopy with a reasonable prognosis.

Diagnosis of lower respiratory tract infections: what we have and what would be nice

STUDY OBJECTIVES

To review the various methods used to diagnose lower respiratory tract infections.

DESIGN

Review of literature with appropriate references to various techniques proposed to diagnose pneumonia.

INTERVENTION

Compare and contrast different proposed approaches to diagnose pneumonia.

RESULTS

Bronchoscopic techniques appear more clear cut for certain nonbacterial pathogens. Their role in immunocompromised patients is more clear cut, while in the nonimmunocompromised patient, invasive diagnostic techniques probably provide a higher certainty of the final diagnosis of the patient. Recent interest has focused on nonbronchoscopic techniques for the mechanically ventilated patient. None of these techniques has been demonstrated to change clinical outcome.

CONCLUSIONS

Diagnosis of lower respiratory tract infection has to be tailored for the individual patient. Decision about which procedure to do is influenced by the patient's underlying immune status, level of illness, and response to empiric therapy.

Pulmonary disease

This article has presented the reader with an overview of the pulmonary disorders that develop during the course of HIV disease with special emphasis on the more commonly encountered entities. This information is intended to prepare the clinician to recognize the hallmark characteristics of the various diseases as well as atypical features. Despite the advances in basic understanding of the clinicopathologic consequences of infection with HIV, a cure has not been realized. There has, however, been success in controlling some of the major pulmonary problems that adversely affect both the quality and the length of life for persons with AIDS. For most complications of HIV infection, prognosis ultimately depends not only on treatment of the specific problem, but also controlling the relentless process of progressive immunosuppression. Continued research into treatment or prevention of HIV infection itself is needed, but at present prevention, rapid diagnosis, and treatment of recognized problems remain an intermediary goal.

Tuberculosis: An Update for Clinicians

Tuberculosis is the most common cause of death due to a single pathogen world wide, and the number of tuberculosis cases in the United States has increased significantly since 1985. Drug-resistant tuberculosis is also increasing, and multidrug-resistant tuberculosis (resistant to isoniazid and rifampin) has fueled deadly epidemics in New York and Florida. The clinical manifestations of tuberculosis in patients with human immunodeficiency virus (HIV) infection are distinctive; chest radiographic findings include primary tuberculosis and an extremely high frequency of extrapulmonary tuberculosis. Promising new diagnostic tests for tuberculosis are based on amplification of mycobacterial DNA by polymerase chain reaction, but they have not yet been adapted to the clinical laboratory. Most tuberculosis patients in the United States should receive initial treatment with isoniazid, rifampin, pyrazinamide, and ethambutol. For drug-susceptible tuberculosis, these drugs are continued for 2 months, followed by isoniazid and rifampin for 4 months, which yields a cure rate of greater than 95%. For isoniazid-resistant organisms, rifampin, pyrazinamide, and ethambutol, with or without isoniazid, can be given for 6 months. For HIV-infected patients with drug-susceptible or isoniazid-resistant tuberculosis, we recommend continuation of therapy for a minimum of 9 months. Most forms of extrapulmonary tuberculosis due to drug-susceptible organisms are treated for 6 months, except for meningeal, miliary, and skeletal tuberculosis, for which a minimum of 12 months of therapy is recommended. To reduce nosocomial transmission of tuberculosis, health cafe facilities should institute administrative controls to reduce exposure to infectious patients, engineering controls to reduce the concentration of infectious droplet nuclei, and personal respiratory protection of health care workers with appropriate masks. Administrative controls are probably the most important part of a tuberculosis infection control program. Health care workers who were recently infected with Mycobacterium tuberculosis can be identified by serial skin testing, and those who convert their skin tests from negative to positive should receive chemoprophylaxis with isoniazid to prevent development of tuberculosis.

Comparative histopathological study of pulmonary tuberculosis in human immunodeficiency virus-infected and non-infected patients

SETTING

Clinical features of human immunodeficiency virus (HIV)-associated tuberculosis depend upon the patients' residual immunity. An immune-dependent presentation has also been described at the histopathological level in many extra-pulmonary sites, but no descriptions have so far been made on the histopathology of HIV-associated pulmonary tuberculosis.

OBJECTIVE

To compare the histopathological features of pulmonary tuberculosis in HIV-infected subjects and seronegative patients.

DESIGN

We carried out a retrospective comparative study on 16 HIV-infected subjects and 16 seronegative patients with culture-proven pulmonary tuberculosis who underwent transbronchial biopsy. We evaluated the bacillary burden and the parenchymal inflammatory reaction by means of a four-graded scoring system giving an approximate quantitative measure of the two parameters.

RESULTS

HIV-associated pulmonary tuberculosis was found to differ significantly from disease forms seen in seronegative patients, with a significant tendency to develop highly bacillary and poorly reactive histopathological pictures along with the downgrading evolution of immune function.

CONCLUSION

Pathologic features of pulmonary tuberculosis in HIV-infected subjects differ from those encountered in seronegative patients depending upon the individual immunity of the former. HIV-associated progressive depletion of CD4+ lymphocytes leads to substantial changes in pulmonary reactivity to Mycobacterium tuberculosis; multibacillary pictures in a background of loose inflammatory reactions are quite common findings at the extreme phase of HIV-related immune deterioration.

Transbronchial biopsy in the diagnosis of pulmonary infiltrates in immunocompromised patients

Bronchoalveolar lavage (BAL) and transbronchial biopsy (TBB) frequently are performed in the investigation of immunocompromised patients with lung disorders. The risk-benefit ratio of TBB currently is debated, since several authors have found that the less invasive BAL may provide as much information as TBB, with the avoidance of some biopsy-related side effects. We retrospectively evaluated 157 instances of bronchoscopy carried out on 142 immunocompromised patients, with both BAL and TBB performed in every case. Immunosuppressant conditions were HIV infection (79), hematologic malignancies (36), and antirejection therapy in renal transplant recipients (27). Transbronchial biopsy provided a diagnostic yield significantly higher than that obtained by BAL in all categories investigated; diagnostic rates were 77.3% for TBB and 47.6% for BAL (p < 0.001) in patients with HIV infection, 55 and 20% (p < 0.001) in patients with hematologic malignancies, and 57.5 and 27.2% (p < 0.001) in renal transplant recipients. Looking at the whole series, the diagnostic rates of TBB and BAL were 67.5 and 36.3%, respectively (p < 0.001), with a total additional yield of 33% provided by TBB, while in only 2% of cases BAL gave rise to diagnostic information not achieved by TBB. Considering that side effects followed TBB at a negligible rate (2.5%), we believe that TBB should be routinely carried out in these patients once the diagnostic strategy has been oriented to bronchoscopy.

Bronchoscopic diagnosis of pneumonia

Lower respiratory tract infections are characterized by significant morbidity and mortality but also by a relative inability to establish a specific etiologic agent on clinical grounds alone. With the recognized shortcomings of expectorated or aspirated secretions toward establishing an etiologic diagnosis, clinicians have increasingly used bronchoscopy to obtain diagnostic samples. A variety of specimen types may be obtained, including bronchial washes or brushes, protected specimen brushings, bronchoalveolar lavage, and transbronchial biopsies. Bronchoscopy has been applied in three primary clinical settings, including the immunocompromised host, especially human immunodeficiency virus-infected and organ transplant patients; ventilator-associated pneumonia; and severe, nonresolving community- or hospital-acquired pneumonia in nonventilated patients. In each clinical setting, and for each specimen type, specific laboratory protocols are required to provide maximal information. These protocols should provide for the use of a variety of rapid microscopic and quantitative culture techniques and the use of a variety of specific stains and selective culture to detect unusual organism groups.

Pneumonia in patients with HIV infection

The epidemiologic shift in HIV-infected populations from homosexual men to intravenous drug users and their sexual partners, together with the wide application of antipneumocystis prophylaxis and a better understanding of the broad range of HIV-associated illnesses, has changed our concept of the spectrum of lung infections that occur in patients with HIV infection. Bacterial pneumonia, not PCP, is the most common lower respiratory infection. Newer therapies of mild-to-moderate PCP increase the treatment options. The worldwide increase in tuberculosis cases is attributable to coinfection with HIV, and multidrug-resistant tuberculosis is now a serious threat, especially in the inner cities. Fungal pneumonias occur with increased frequency in patients with HIV infection, depending on the geographic factors and the severity of immunodeficiency.

Endobronchial lesions in HIV-infected individuals

Endobronchial manifestations of HIV infection are rare. The endobronchial appearance and clinical presentation of these lesions may suggest the correct diagnosis. Establishing an appropriate differential diagnosis at the time of visualization of the endobronchial lesion is important because some lesions require specific biopsy techniques or special stains. The bronchoscopist must consider the risks vs benefits of biopsy when confronted with an endobronchial lesion. With the notable exception of pseudomembranous necrotizing tracheobronchial aspergillosis, there are no specific endobronchial lesions associated with HIV infection which increase the risk of complications when they are biopsied. Although EKS is a vascular lesion and an early case report suggested that endobronchial biopsy might result in excessive bleeding, this complication was not observed in two subsequent series. Fortunately, a presumptive diagnosis of EKS can usually be made without biopsy by the characteristic appearance of the lesions. EKS is the most common endobronchial lesion associated with HIV infection; however, its incidence will probably decline as the incidence of KS declines. Many of the other endobronchial lesions described herein have been reported recently. We suspect these and other lesions will be found more frequently, as the epidemic of HIV continues to evolve.

Tuberculosis in patients with HIV infection

Tuberculosis is the most common opportunistic infection in patients with HIV infection worldwide and is the only one that is transmissible to others by the respiratory route. Tuberculosis is curable and preventable. Early detection of tuberculosis disease and infection in individuals with or at risk for HIV infection is paramount. This approach can minimize the devastating interaction between these two diseases.