Early diagnosis of tuberculosis by fibreoptic bronchoscopy

A Comparative Study of Induced Sputum and Bronchial Washings in Diagnosing Sputum Smear Negative Pulmonary Tuberculosis

INTRODUCTION

Tuberculosis is one of the most important public health problem worldwide. Detecting patients with active pulmonary Koch's disease is an important component of tuberculosis control programs. However, at times in patients even with a compatible clinical picture, sputum smears do not reveal acid-fast bacilli and smear-negative pulmonary tuberculosis remains a common problem.

AIM

The present study is aimed to compare the results of induced sputum and bronchial washings smear in patients suspected to have sputum smear negative pulmonary tuberculosis.

MATERIALS AND METHODS

A prospective study conducted from August 2014 to July 2015, comprising 120 patients fulfilling study criteria. Patients with respiratory symptoms and chest roentgenogram suspicious of pulmonary tuberculosis with no previous history of anti-tuberculosis treatment and two spontaneous sputum smear samples negative for acid fast bacilli were included. Patients with active haemoptysis and sputum positive were excluded from the study. Sputum induction was done by using 5-10 ml of 3% hypertonic saline through ultrasonic nebulizer taking safety precautions. All the patient underwent fibreoptic bronchoscopy after six hours fasting on the same day. About 20 ml of normal saline instilled into the suspected pathology area and washings were taken with gentle suction. The sample processing and fluorescent staining for acid fast bacilli was done in a designated microscopy lab.

RESULTS

Out of 120 sputum smear negative pulmonary tuberculosis patients, induced sputum smear examination detected acid fast bacilli in 76 patients (63.3%) and acid fast bacilli detected from bronchial washings in 94 patients (78.3%). Smear positivity was higher in cavitary and infiltrative lesions as compared to consolidation and infrahilar pattern disease.

CONCLUSION

Even though both induced sputum and bronchial washings procedures were valuable for the diagnosis of sputum smear negative, sputum induction with hypertonic saline should be the initial procedure of choice, which can be repeated twice / thrice in a day or two consecutive days. If the patient still remains induced sputum smear negative and if the clinical probability of tuberculosis is high, starting anti-tuberculosis treatment and closely monitoring patient and reserving bronchoscopy to those patients who do not improve and to exclude alternative diagnosis seems to be a practically useful approach.

Induced sputum versus bronchial washings in the diagnosis of sputum negative pulmonary tuberculosis

Introduction:

Tuberculosis (TB) is one of the most important public health problems worldwide. Detecting patients with active pulmonary TB (PT) is an important component of TB control programs. However, at times in patients even with a compatible clinical picture, sputum smears do not reveal acid-fast bacilli (AFB) and smear-negative PT remains a common problem. This study compares the results of induced sputum (IS) and bronchial washings (BWs) in detecting sputum negative PT.

Materials and Methods:

A prospective study conducted from June 2014 to June 2015, comprising 120 patients fulfilling study criteria. Patients with respiratory symptoms and chest roentgenogram suspicious of PT with no previous history of antiTB treatment (ATT) and two spontaneous sputum smear samples negative for AFB were included in the study. Patients with active hemoptysis and sputum positive were excluded from the study. Sputum induction was done using 5–10 ml of 3% hypertonic saline through ultrasonic nebulizer taking safety precautions. All the patients underwent fiberoptic bronchoscopy after 6 h fasting on the same day. About 20 ml of normal saline instilled into the suspected pathology area and washings were taken with gentle suction. The sample processing and fluorescent staining for AFB were done in a designated microscopy laboratory.

Results:

Of 120 smear-negative PT patients, IS smear examination detected AFB in 76 patients (63.3%) and AFB detected from BWs in 94 patients (78.5%). Smear positivity higher in cavitary and infiltrative lesions compared to consolidation and infrahilar pattern disease.

Conclusions:

Even though both IS and BWs procedures were valuable for the diagnosis of smear-negative TB, sputum induction with hypertonic saline should be the initial procedure of choice, which can be repeated twice/thrice in a day or 2 consecutive days. If the patient remains IS smear-negative and if the clinical probability of TB is high, starting ATT and closely monitoring patient and reserving bronchoscopy to those patients who do not improve and to exclude alternative diagnosis seems to be a practically useful approach.

Investigation of endobronchial tuberculosis diagnoses in 22 cases

BACKGROUND

Endobronchial tuberculosis (EBTB) is a special form of pulmonary tuberculosis. In spite of much progress in the diagnosis of this disease in past years, delayed or mistaken diagnosis is still commonly seen.

OBJECTIVE

The aim of this study is to try to find out some useful clues for the diagnosis of EBTB, especially the early diagnosis.

METHODS

The medical records of patients with EBTB were analyzed retrospectively.

RESULTS

The male-to-female ratio was 1:2.2 out of 22 patients. Patients aged below 60-years-old constituted 72.7% of the cases. 22.7% of these patients were smokers. The male-to-female ratio of smokers was 4:1. 68.2% of these patients tested all showed negative result for the HIV test. The frequent complaints were cough, sputum, shortness of breath and fever, and antibiotic treatments were usually inefficacious. Multiple lobes lesion, exudative shadow and atelectasis were the frequent radiological findings. Acid-fast bacilli staining for sputum smear was positive in only 13.6% of these patients. Tuberculin skin test was positive in 59.1% of these patients. Granular lesion was the most common bronchoscopic appearance in these patients. Histological changes showed distinctive tuberculose lesion in 72.2% of 18 patients undergoing bronchoscopic biopsy.

CONCLUSION

The diagnosis of EBTB is easily delayed or mistaken because of nonspecific clinical manifestations and the low incidence of positive acid-fast bacilli staining. A high index of awareness of this disease is required for diagnosis. Bronchoscopy should be performed as soon as possible in suspected patients, especially when patients present positive tuberculin skin test or no response to antibiotic treatments.

Fiberoptic bronchoscopy, as a valuable diagnostic option in sputum negative pulmonary tuberculosis: A prospective study

CONTEXT

World Health Organization recommends bacteriological confirmation of pulmonary tuberculosis (PTB) by the detection of acid-fast bacilli (AFB) in respiratory specimens. However about 40-60% of patients with PTB suspected clinically or radiologically may fail to produce sputum, or when it is available, AFB may be negative on repeated smear examination. These sputum smear negative patients and those who fail to produce any sputum can be diagnosed by flexible fiberoptic bronchoscopy.

AIMS

Our study was an attempt to analyze the role of fiberoptic bronchoscopy in sputum smear negative PTB patients with respect to their association with clinical and radiological profile.

MATERIALS AND METHODS

In this prospective, open label, observational study, 40 cases of sputum smear negative PTB were subjected to bronchoscopic examination after taking informed consent and samples like bronchial aspirate, bronchoalveolar lavage and post bronchoscopy sputum were collected. The data was analysed and the results were given in percentage.

RESULTS

Out of the total 40 patients, overall diagnosis was confirmed in 24 (60%) patients. Of these 24 patients, 17 patients were confirmed for PTB whereas 7 had other diagnoses.

CONCLUSION

The study concludes that fiberoptic bronchoscopy is a useful tool in diagnosing sputum smear negative PTB patients with respect to their association with clinical and radiological profile, and also identifies individuals at a higher risk for progression of disease, at an early stage despite not meeting routine bacteriological criteria for confirmation of PTB.

Diagnosing sputum/smear-negative pulmonary tuberculosis: Does fibre-optic bronchoscopy play a significant role?

Background:

Diagnosis of sputum/smear-negative pulmonary tuberculosis patients can be both challenging and time consuming with many patients being put on empirical anti-tubercular treatment. Fibreoptic bronchoscopy may provide a confirmative and early diagnosis in such patients.

Aims:

To assess the role of fibreoptic bronchoscopy in the diagnosis of sputum /smear-negative pulmonary tuberculosis.

Materials and Methods:

The study was conducted on 75 suspected sputum / smear-negative pulmonary tuberculosis cases attending Pulmonary Medicine Department of Mamata Medical College and Hospital, Khammam, AP. Fibreoptic bronchoscopy was performed; culture of sputum and bronchial washings for Mycobacterium tuberculosis was done by BACTEC method.

Results:

A final diagnosis of sputum /smear-negative pulmonary tuberculosis was made in 60 patients. Bronchial washings smear for acid-fast bacilli (AFB) was positive in 21 patients while culture of bronchial washings was positive in 39 patients. In 29 patients, smear or culture of bronchial washing alone contributed to the final diagnosis. Total yield of bronchoscopy in diagnosis of sputum smear negative pulmonary tuberculosis was 83.33% (50/60); bronchoscopy was the only diagnostic method in 66% cases (40/60) with bronchial washings being the only diagnostic method in 48.33%. Bronchial washings smear for AFB and histopathological evidence of caseating granuloma made immediate diagnosis possible in 48.33% (29/60) patients.

Conclusion:

Our study suggests that fibreoptic bronchoscopy can provide excellent material for diagnosis of suspected cases of Pulmonary Tuberculosis in whom smears of expectorated sputum do not reveal mycobacteria.

Endobronchial tuberculosis: an overview

Endobronchial tuberculosis (EBTB), of which the incidence has been increasing in recent years, is a special type of pulmonary tuberculosis. The endobronchial tuberculose focuses often injure the tracheobronchial wall and lead to tracheobronchial stenosis. The tracheobronchial stenosis may cause intractable tuberculosis and make patients become chronic infection sources of tuberculosis, or may even cause pulmonary complications and result in death. The etiological confirmation of Mycobacterium tuberculosis is most substantial for diagnosis. However, because the positive rate of acid-fast bacillus staining for sputum smears is low and the clinical and radiological findings are usually nondistinctive, the diagnosis of EBTB is often mistaken and delayed. For early diagnosis, a high index of awareness of this disease is required and the bronchoscopy should be performed as soon as possible in suspected patients. The eradication of Mycobacterium tuberculosis and the prevention of tracheobronchial stenosis are two most substantial treatment goals. To get treatment goals, the diagnosis must be established early and aggressive treatments must be performed before the disease progresses too far.

Usefulness of induced sputum and fibreoptic bronchoscopy specimens in the diagnosis of pulmonary tuberculosis

We investigated the diagnostic value of induced sputum (IS) and bronchial lavage (BL) specimens in patients with suspected pulmonary tuberculosis who had negative spontaneous sputum specimens or who were unable to produce sputum spontaneously. IS specimens and BL specimens obtained using flexible fibreoptic bronchoscopy from 55 patients were evaluated for the presence of acid-fast bacilli (AFB) and cultured for Mycobacterium tuberculosis. Positive results were found with IS smear in 23 patients, BL smear in 26 patients, and IS or BL culture in 42 patients. Culture of BL specimens had a higher sensitivity than IS or BL smears or culture of IS specimens. The highest sensitivity rate was obtained with a positive BL or IS culture (86%). For early diagnosis (a positive IS or BL smear), the sensitivity was 57%. IS has a higher sensitivity rate than spontaneous sputum for the detection of tuberculosis, and fibreoptic bronchoscopy is useful for the early diagnosis of tuberculosis when AFB are not detected in spontaneous or induced sputum specimens.

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.

Adequately washed bronchoscope does not induce false-positive amplification tests on bronchial aspirates in the diagnosis of pulmonary tuberculosis

STUDY OBJECTIVES

To investigate the clinical usefulness of amplification (COBAS AMPLICOR; Roche Diagnostics Systems; Branchburg, NJ) on bronchoscopic aspirate specimens in the diagnosis of pulmonary tuberculosis, with particular regard to the possibility of false-positive results in subsequent specimens due to residual Mycobacterium tuberculosis DNA.

DESIGN AND SETTING

A prospective clinical study at a tertiary referral medical center.

PARTICIPANTS AND METHODS

Four hundred fiberoptic bronchoscopic procedures were performed, using seven bronchoscopes on 335 consecutive patients, for therapeutic or diagnostic purposes. Serial bronchial aspirates were collected and tested for M tuberculosis, using COBAS AMPLICOR (CA). Bronchoscopes were cleaned and disinfected automatically, between patient use, by the same endoscope washer. The name of each bronchoscope and the sequence of its use were recorded, together with the sequence of washing. The CA results were compared with the bacteriologic and histologic results for M tuberculosis infection. When there was a suspicion of contamination, outward polymerase chain reaction analysis was performed.

RESULTS

Of 392 specimens (332 subjects), excluding the 8 specimens (4 subjects) in which bacteriologic and histologic analyses were omitted, a smear-positive result for acid-fast bacilli (AFB), culture-positive or biopsy-positive results, and CA-positive results were obtained in 16, 49, and 32 specimens, respectively. In AFB smear-positive subjects, the sensitivity, specificity, positive predictive values (PPVs), and negative predictive values (NPVs) were 92%, 67%, 92%, and 67%, respectively. In AFB smear-negative subjects, the sensitivity, specificity, PPV, and NPV values were 38%, 99%, 74%, and 94%, respectively. The CA test was more sensitive than the AFB smears for the diagnosis of pulmonary tuberculosis (53% vs 27%, respectively; p < 0.05). False-positive CA results were seen in only six specimens. Three of these six subjects received a diagnosis of pulmonary tuberculosis on clinical and radiologic grounds, and none of the six results seemed to be associated with bronchoscopic cross-contamination.

CONCLUSIONS

Adequately cleaned and disinfected bronchoscopes did not cause false-positive amplification test results for M tuberculosis on bronchial aspirates by cross-contamination. Furthermore, sensitivity was greater with the CA tests. Therefore, CA tests on bronchial aspirates seem to be useful in the diagnosis of pulmonary tuberculosis.

Rapid diagnosis of smear-negative pulmonary tuberculosis via fibreoptic bronchoscopy: utility of polymerase chain reaction in bronchial aspirates as an adjunct to transbronchial biopsies

Fibreoptic bronchoscopy was performed on 190 patients with chest radiographic lesions and negative sputum smears for acid-fast bacilli. Aside from obtaining transbronchial biopsies for histological examination, bronchial aspirate specimens were also tested for Mycobacterium tuberculosis complex DNA by a conventional polymerase chain reaction (PCR) technique. Of 177 transbronchial biopsies performed, a diagnosis was found in 64 cases [43 cases of tuberculosis (TB), 17 cases of lung carcinoma and four cases of other infective/inflammatory diseases] giving a diagnostic yield of 36.2%. PCR was positive in 105 of 108 finally diagnosed cases of TB and 22 of 82 non-TB cases. The sensitivity, specificity, positive predictive value and negative predictive value of PCR when applied to bronchial aspirate specimens for diagnosing smear-negative pulmonary TB were 97.2%, 73.2%, 82.7% and 95.2% respectively. Therefore, detection of M. tuberculosis complex DNA in bronchial aspirates by PCR might have an adjunctive place to transbronchial biopsies in the rapid diagnosis of smear-negative pulmonary tuberculosis.

Issues in the management of contacts of patients with active pulmonary tuberculosis

The evidence regarding the transmission of tuberculosis and risk of infection and disease in several specific clinical situations has been reviewed. There is considerable epidemiologic evidence that contagiousness is not an all-or-nothing phenomenon and is affected by several factors, only one of which is the bacteriologic status of the patient's sputum. Although untreated smear negative, culture positive patients are less contagious on average, they still may transmit infection to their close and casual contacts. Compared with contacts with tuberculin conversion, persons who are already tuberculin positive have much lower risk of developing active tuberculosis after exposure, and persons with prior BCG vaccination are at somewhat lower risk. Preventive therapy will be of less benefit, but should still be recommended for contacts who are heavily exposed or are immune compromised. Epidemiologic studies using RFLP techniques could provide more precise answers to the questions in this review.

Value of bronchoalveolar lavage and gastric lavage in the diagnosis of pulmonary tuberculosis in children

OBJECTIVE

The aim of our study was to find out if bronchoalveolar lavage (BAL) would be better than gastric lavage for the isolation of Mycobacterium tuberculosis from pediatric patients with suspected pulmonary tuberculosis.

DESIGN

50 children with suspected pulmonary tuberculosis at a mean age of 5.1 years (range 7 months to 12 years) were studied. Early morning gastric lavage was collected. Flexible bronchoscopy and bronchoalveolar lavage was performed under local anaesthesia after obtaining informed consent from the parents. The BAL fluid and gastric lavage specimens were subjected to smear examination for acid-fast bacilli (AFB) and culture for mycobacteria using established methods.

RESULTS

Of the 50 cases, M. tuberculosis was grown in 6 BAL samples (12%) and 16 gastric lavage samples (32%) making a total of 17 culture proven cases (34%). Out of the 6 BAL positive cases, gastric lavage was also positive in 5 cases.

CONCLUSION

We conclude that gastric lavage is better than BAL for bacteriologic confirmation of pulmonary tuberculosis in children. The overall bacteriologic yield combining both procedures was 34% while gastric lavage alone was positive in 32% of the cases.