The Roles of HRCT and Clinical Parameters in Assessing Activity of Suspected Smear Negative Pulmonary Tuberculosis

Relevance of the correlation between tomography findings and laboratory test results in the accuracy of the diagnosis of pulmonary tuberculosis

Objective

To evaluate the correlation between multidetector computed tomography (MDCT) findings and laboratory test results in patients with pulmonary tuberculosis (PTB).

Materials and Methods

A total of 57 patients were evaluated. Patients with suspected PTB were divided into groups according to the final diagnosis (confirmed or excluded), and the groups were compared in terms of sociodemographic variables, clinical symptoms, tomography findings, and laboratory test results.

Results

Among the patients with a confirmed diagnosis of PTB, small pulmonary nodules with a peribronchovascular distribution were significantly more common in the patients with a positive sputum smear microscopy result (47.4% vs. 8.3%; p = 0.046), as were a miliary pattern (36.8% vs. 0.0%; p = 0.026), septal thickening (84.2% vs. 41.7%; p = 0.021), and lymph node enlargement (52.6% vs. 8.3%; p = 0.020). Small pulmonary nodules with a centrilobular distribution were significantly more common among the culture-positive patients (75.0% vs. 35.7%; p = 0.045), as was a tree-in-bud pattern (91.7% vs. 42.9%; p = 0.014). A tree-in-bud pattern, one of the main tomography findings characteristic of PTB, had a sensitivity, specificity, positive predictive value, and negative predictive value of 71.0%, 73.1%, 75.9%, and 67.9%, respectively.

Conclusion

MDCT presented reliable predictive values for the main tomography findings in the diagnosis of PTB, being a safe tool for the diagnosis of PTB in patients with clinical suspicion of the disease. It also appears to be a suitable tool for the selection of patients who are candidates for more complex, invasive examinations from among those with high clinical suspicion of PTB and a negative sputum smear microscopy result.

Diagnostic value of bronchoscopy in sputum-negative pulmonary tuberculosis patients and its correlation with clinicoradiological features

CONTEXT:

Tuberculosis (TB) remains endemic in Saudi Arabia. Little local data have been reported on bronchoscopic evaluation of sputum-negative pulmonary TB patients, which poses a significant diagnostic and therapeutic challenge.

AIMS:

To determine the diagnostic value of bronchoscopy and bronchoalveolar lavage (BAL) and its correlation with clinical and radiological features in sputum-negative, culture-confirmed pulmonary TB patients.

METHODS:

We performed a retrospective analysis of patients with definite or probable pulmonary TB with overall negative (smear and/or polymerase chain reaction [PCR]) or scanty sputum that had undergone bronchoscopy with BAL over a period of 5 years. Patients’ symptoms, radiological features, lung lobe lavaged, BAL acid-fast bacilli (AFB) stain, Mycobacterium TB (MTB)-PCR, and mycobacterial cultures were analyzed. Mycobacterial cultures (either sputum or BAL) were used as a reference standard.

RESULTS:

Out of 154 patients, 49 (32%) were overall sputum negative and underwent a diagnostic bronchoscopy. Dry cough and fever were the most common symptoms. Uncontrolled diabetes mellitus was the most frequent comorbidity identified in 15 (31%) patients. Fifty-nine percent of the patients had diffuse lung infiltrates, with consolidation being the most common abnormality (41%), followed by cavitation (39%). Right upper lobe was the most frequent lung lobe lavaged (31%), while transbronchial lung biopsies (TBLB) were obtained in 21 (43%). BAL mycobacterial culture and MTB PCR were positive in 35 (71%) and 23 (47%) patients, respectively. Combined BAL MTB PCR and TBLB provided rapid diagnosis in 28 (57%) patients.

CONCLUSIONS:

An overall diagnostic yield of 90% was achieved with combined use of BAL MTB PCR, culture, and histopathology. Upper lobe lavage and presence of cavities on chest imaging had a higher diagnostic yield.

Clinico-radiological and bronchoscopic predictors of microbiological yield in sputum negative tuberculosis in Pakistan

To determine association of clinico-radiological factors and radiological activity with diagnostic yield in sputum-smear negative tuberculosis (TB). Prospective observational study in Military Hospital Rawalpindi from July to December 2018. Adult patients having no contraindications to bronchoscopy were included. HIV positive patients and those on anti-tuberculosis therapy for more than one week were excluded. High-Resolution Computed tomography (HRCT) findings were classified based on active and inactive tuberculosis features. Washings were sent for Acid-Fast Bacillus (AFB) smear, GeneXpert assay and cultures. Out of 215 patients, 42.3% (91) were diagnosed with microbiological or histological evidence of TB. On univariate analysis, cavitation (p-value <0.001), soft-tissue nodules (p-value 0.04), and endobronchial mucosal changes (p-value 0.02) were associated with culture positivity. Presence of cavitation (OR= 4.10; CI= 2.18,7.73; p-value<0.001) was the only independent predictor of microbiological yield. Diagnostic yield was 70%, 50%, 12.5% and 8.6% in patients with definitely active, probably active, indeterminate and inactive tuberculosis HRCT features respectively. Sensitivity, specificity, positive predictive value and negative predictive value of HRCT active TB were 95.38% (95% CI 87.10 -99.04), 48.00 % (95% CI 39.78 -56.30), 44.29% (95% CI 40.31 -48.33), 96.00 % (95%CI 88.70 -98.66) respectively. There was no significant association between age groups, smoking status and gender with diagnosis of tuberculosis in our study. Radiological activity and certain visualized bronchoscopic changes were associated with good diagnostic performance and can be used as predictive factors in diagnosis of active smear negative tuberculosis.

A descriptive study of smear negative pulmonary tuberculosis in a high HIV burden patient's population in North Central Nigeria

Tuberculosis (TB) is a serious disease of public health concern, mainly in low- and middle-income countries. Most of these countries have challenges in diagnosis and treatment of TB in people with smear-negative pulmonary tuberculosis (SNPTB), which remains a significant public health challenge because of the global burden of the disease. We evaluated the epidemiology and clinical presentation of SNPTB in a cohort of patients with high HIV burden. The study was a cross-sectional study among patients with SNPTB in four major hospitals that care for TB/HIV patients in north-central Nigeria. All patients 18 years and above who were newly diagnosed as SNPTB, or patients with SNPTB who had not taken TB drugs for up to 2 weeks irrespective of their HIV status were recruited. Demographic data (sex, age), smoking status, and medical history (clinical form of TB, symptoms at admission, diagnostic methods, presence of comorbidities, prior TB treatment) were obtained using a semi-structured questionnaire. Detailed clinical examination was also done on all the study subjects. Baseline results of packed cell volume, HIV test and sputum acid fast bacilli done during TB screening were retrieved from the patients' case notes and recorded. Also, the base line Chest X-ray films taken during TB screening were reviewed and reported by two radiologists blinded to each other's reports. The Xpert MTB/RIF tests and sputum culture (using LJ medium) were done in a TB reference laboratory. A total of 150 patients with SNPTB were studied. Majority of the patients were female 93 (62%). The median age of the patients was 36.5 years with greater percentage of the patients within the ages of 25-44 years 92 (61.3%). Twenty-two (14.7%) of the patients had previous TB treatment. History of cigarette smoking was obtained in only 7(4.7%) of the patients while 82 (64.1%) were HIV positive. All the patients had a history of cough for over a period of at least three weeks, while, 27 (18%) reported having hemoptysis. About 87 (58%) had fever and 110 (73.7%) had anemia, while weight loss and night sweat were reported in 98(65.3%) and 82 (54.7%) of the patients respectively. Chest x rays were reported as typical of TB in only 24 (16%) of the patients. Of the 150 sputa sample analyzed, 21/150 (14.0%) and 22/150 (14.7%) where Gene Xpert and sputum culture positive respectively. The sensitivity and specificity of Gene Xpert assay were 81.8% (18/22; 95% CI 61.5 to 92.7%) and 97.4% (112/115; 95% CI 92.6 to 99.1%), respectively. The study found cough, fever and anemia to be the commonest presentation in patient with SNPTB in a high HIV burden patient's population. There is also relatively high culture positivity among the patients. This underscores the need to expand the facilities for culture and confirmation in TB centers across the country.

Role of Xpert MTB/RIF in Bronchoalveolar lavage fluid of sputum-scarce, suspected Pulmonary TB patients

Setting

A prospective observational study conducted in Medical college hospital, in a high-TB- prevalence region of northern Telangana, India.

Objective

To know the diagnostic role of Xpert MTB/RIF assay in bronchoalveolar lavage fluid (BALF) in sputum-scarce, suspected pulmonary tuberculosis (PTB) patients.

Design

Study period was between October 2014 and March 2017. Suspected pulmonary tuberculosis patients aged 15 years or more, who were sputum-scarce and conforming to the inclusion criteria were submitted to bronchoscopy. BALF thus obtained was submitted to smear for acid fast bacilli (AFB) and Xpert MTB/RIF assay as index tests along with culture for Mycobacterium tuberculosis complex (MTBC). Culture for M. tuberculosis complex was considered as gold standard for the diagnosis of PTB. The sensitivity, specificity and predictive values were calculated for smear AFB and Xpert MTB/RIF assay.

Results

56 of the 81 patients were included and evaluated in the final analysis. In 10 of these 56 patients PTB was confirmed by culture positivity. The sensitivity and specificity of Xpert MTB/RIF assay was 90% (9/10,95%CI 59.6- 98.2) and 52.2% (24/46, 95%CI 38. 1-65.9) respectively and that of the smear AFB was 60% (6/10, 95%CI 31.2–83.1) and 67.4% (31/46, 95%CI 53.0–79.1). All the patients considered ‘probable’ PTB (pending culture results), were administered antituberculous treatment and showed complete clinicoradiological improvement on follow up. Three of the 31 Xpert MTB/RIF positive patients were detected as resistance to rifampicin (RR).

Conclusions

Xpert MTB/RIF assay of BALF in the study cohort provides rapid diagnosis of Mycobacterium tuberculosis, and detection of rifampicin resistance at the very outset, aiding in selection of appropriate ATT regimen. In this context, it can be recommended as the first line investigation. Xpert MTB/RIF assay aided by HRCT Chest and suggestive clinical presentation may be helpful in early institution of ATT especially in smear negative, culture negative cases.

Correlation of microbiological yield with radiographic activity on chest computed tomography in cases of suspected pulmonary tuberculosis

BACKGROUND

Little is known about the correlation between microbiological yield and radiographic activity, on chest computed tomography (CT), in suspected pulmonary tuberculosis (PTB) cases, despite CT being widely used, clinically.

METHODS

We used multicenter retrospective data, obtained from medical records, focusing on the diagnostic performance for definite PTB. We categorized patients into four groups, by radiographic activity: definitely active, probably active, indeterminate activity, and probably inactive.

RESULTS

Of the 650 patients included, 316 had culture-confirmed PTB; 190 (29.2%), 323 (49.7%), 70 (10.8%), and 67 (10.3%) were classified into the definitely active, probably active, indeterminate activity, and probably inactive groups, respectively. The corresponding observed culture rates for CT radiographic activity were 61.6%, 60.7%, 4.3% and 0%, respectively. When not only culture rates but TB-PCR and histological results were taken into consideration as definite PTB, it showed 66.6%, 67.2%, 14.3%, and 0% of each CT radiographic activity, respectively. Regarding the diagnostic performance for definite PTB, radiographic activity displayed high sensitivity (97.1%, 95% confidence interval (CI), 94.6-98.5) and negative predictive values (92.7%, 95% CI, 86.6-96.2), considered definitely and probably active PTB. Apart from PTB, other etiologies, according to radiographic activity, were predominantly respiratory infections such as bacterial pneumonia and non-tuberculous mycobacterial infection.

CONCLUSIONS

Radiographic activity showed good diagnostic performance, and can be used easily in clinical practice. However, clinicians should consider other possibilities, because radiologic images do not confirm microbiological PTB.

Role of flexible bronchoscopy in patients with sputum-negative pulmonary tuberculosis

BACKGROUND

Pulmonary tuberculosis is one of the major health concerns in the developing countries. Isolation of acid-fast bacilli (AFB) or tuberculosis bacilli from the sputum is required for the diagnosis. A proportion of suspected pulmonary tuberculosis (PTB) cases either clinically or radiologically will not produce sputum or will have sputum negative for AFB. These subsets of cases pose a diagnostic challenge to the treating clinicians. In this study, we present our experience and outcomes with flexible bronchoscopy in patients with sputum-negative pulmonary tuberculosis.

MATERIALS AND METHODS

This was a prospective cross-sectional study, conducted at SDS Tuberculosis research Centre and Rajiv Gandhi Institute of Chest Diseases, Bengaluru, India, from 2010 to 2016. A total of 1095 flexible bronchoscopies were done during this period, out of which 180 were patients with sputum negative for AFB, but were strongly suspected to have pulmonary tuberculosis on clinical examination or radiologically. There were 106 males and 74 females. The age ranged between 11 and 68 years. All patients underwent complete evaluation of the tracheobronchial tree followed by bronchoalveolar lavage (BAL). Microbiological studies used were Ziehl-Neelsen (ZN) staining and culture in Lowenstein-Jensen (LJ) medium. Mucosal lesions suspected of tuberculosis were subjected to biopsy and histopathological confirmation. The data was analyzed.

RESULTS

Out of 180 patients, 106 (58.88%) cases had positive AFB smear on BAL. The culture confirmed the diagnosis of pulmonary tuberculosis in 120 cases (66.66%). Histopathology showed caseous granuloma in 38 (42.22%) cases, nonspecific inflammation in 40 (44.44%) cases, and malignancy in 12 (13.33%) cases out of 90 cases, who underwent biopsy. There were no post-procedural complications.

CONCLUSION

Bronchoscopy is the useful tool in the diagnosis of pulmonary tuberculosis in patients with sputum-negative pulmonary tuberculosis. It is also helpful in differentiating conditions having the clinical picture that mimics pulmonary tuberculosis.

Impact of introduction of Xpert MTB/RIF test on tuberculosis (TB) diagnosis in a city with high TB incidence in Brazil

Background

Xpert MTB/RIF is increasingly used in many countries as the initial diagnostic test for tuberculosis (TB). Few studies have evaluated the effect of Xpert on TB diagnosis under programmatic conditions in Brazil. The aim of the present study was to evaluate the impact of introduction of Xpert MTB/RIF on TB diagnosis in a city with high TB incidence in Brazil.

Methods

We included patients evaluated with conventional diagnostic tests during one year before Xpert introduction (pre-Xpert group) and patients evaluated using Xpert during one year after the test introduction (post-Xpert group).

Results

620 patients met the inclusion criteria (208 in the pre-Xpert group and 412 in the post-Xpert group) and were included in the analysis. The time until TB diagnosis was shorter in post-Xpert group (0.7 day, IQR: 0.5–1.0 day) than in pre-Xpert group (2.0 days, IQR: 2.0–2.0 days) (p<0.0001). Atypical disease characteristics, such as less weight loss, fever, dyspnea, night sweats, and hemoptysis; a negative sputum smear; a negative culture, and a chest X-ray atypical of TB were more common in post-Xpert group than in pre-Xpert group (p<0.0001 for all).

Conclusions

We found that the implementation of the Xpert MTB/RIF assay, under programmatic conditions, improve and facilitate TB diagnosis, especially in cases with atypical disease manifestations. These results are likely to be generalizable to settings with a similar high TB incidence.

Polymerase chain reaction test in induced sputum of patients with pulmonary tuberculosis

INTRODUCTION

Induced sputum (IS) is an alternative method of obtaining sputum, but IS smears are frequently negative. Culture is more time consuming in its results, and less useful to guide the diagnosis. Polymerase chain reaction (PCR) is the most common methodology for rapid diagnosis of tuberculosis (TB), and few studies evaluated its role in IS samples.

OBJECTIVES

The objective of this study is to determine the diagnostic yield of PCR for TB compared with culture in IS samples.

MATERIALS AND METHODS

Prospective study. Inpatients and outpatients of >18 years with respiratory symptoms suggestive of PTB were invited to participate. The subjects were interviewed using a standardized questionnaire, and collected IS. Three samples were obtained for AFB smear and culture. A fourth sample was obtained for PCR test.

RESULTS

A total of 116 IS samples were evaluated. The sensitivity, specificity, positive predictive value and negative predictive values of PCR were 95.2%, 48.4%, 29.0% and 97.9%, respectively. The area under the receiver operating characteristic curve was .72 for the PCR test (P < .0001).

CONCLUSIONS

Although the PCR specificity could be underestimated, if we consider PCR to be more sensitive than the culture method used, we believed that these PCR-positive tests mean false positives. The results of PCR should always be interpreted carefully in conjunction with clinical information.

Clinical diagnostic value of simultaneous amplification and testing for the diagnosis of sputum-scarce pulmonary tuberculosis

BACKGROUND

Since 20% of pulmonary tuberculosis (PTB) patients are asymptomatic, the early detection of PTB is a challenge particularly in sputum-scarce patients and diagnostic accuracy based solely on clinical characteristics and chest X-ray/CT scans are not always satisfactory. The AmpSure simultaneous amplification and testing method for the detection of Mycobacterium tuberculosis (SAT-TB assay) is an alternative approach to diagnose PTB. In the present study, we analyzed the usefulness of the SAT-TB assay for PTB diagnosis in sputum-scarce patients.

METHODS

A total of 840 patients were prospectively enrolled for PTB diagnosis with bronchial alveolar lavage fluid (BALF) used as the samples for the SAT-TB assay. Of these, 536 had a definite diagnosis of PTB confirmed by positive microbiology culture, or clinical diagnosis of active PTB following anti-TB treatment with a favorable response.

RESULTS

The SAT-TB assay showed a 76.44% agreement with the culture test. The sensitivity and specificity of the SAT-TB assay were 50.75% and 94.73%, respectively. The sensitivity of SAT-TB was significantly higher than that of BALF cultures (21.64%) (X² = 49.1503; P < 0.001) and smears (4.48%) (X² = 175.2315; P < 0.001). The specificity of SAT-TB was slightly lower than that of BALF cultures (98.25%) (X² = 2.0727; P = 0.150) and smears (98.25%) (X² = 2.0727; P = 0.150). The accuracy rates were 63.87% for SAT-TB, 44.50% for BALF cultures and 29.84% for BALF smears.

CONCLUSION

The high accuracy of the SAT-TB assay indicated that active PTB is present and anti-TB treatment is strongly recommended regardless of smear and culture test results for sputum scarce active PTB suspected patients when BALF SAT-TB is positive.

Characteristics of Patients with Smear-Negative Pulmonary Tuberculosis (TB) in a Region with High TB and HIV Prevalence

Introduction

Smear-negative pulmonary TB (SNPT) represents 30–60% of all pulmonary TB cases. The mortality of these patients can reach 25% in populations with high prevalence of HIV infection, and 10–20% of TB transmission at the population level are attributable to SNPT cases.

Methods

We conducted a retrospective study to evaluate epidemiological, clinical, and radiological characteristics of patients with SNPT and to compare these with patients who were diagnosed as having smear-positive pulmonary TB (SPPT). All adult patients (≥ 18 years old) with a positive culture for Mycobacterium tuberculosis, and a diagnosis of pulmonary TB were included in the study.

Results

198 patients met the inclusion criteria (positive culture for Mycobacterium tuberculosis) and were included in the analysis. Of these patients, 69 (34.8%) were smear positive (SPPT) and 129 (65.2%) were smear negative (SNPT). In univariate analysis, cough, dyspnea, and hemoptysis were less frequent in SNPT patients in comparison with SPPT patients. In a multivariate model, having no cough and no radiographic pattern typical of TB were the characteristics independently associated with a diagnosis of SNPT.

Conclusions

We found a very high prevalence of SNPT among patients with TB in a setting with high TB and HIV prevalence. The absence of cough in the presence of other symptoms suggestive of TB, and having no radiographic pattern typical of TB where independent predictors of SNPT.

Efficacy of Induced Sputum for the Diagnosis of Pulmonary Tuberculosis in Adults Unable to Expectorate Sputum

Background

Induced sputum (IS) has been used to collect airway secretions in subjects who have inadequate sputum production. The aim of this study was to investigate the efficacy of IS for the diagnosis of pulmonary tuberculosis (PTB) in adults unable to expectorate sputum.

Methods

Medical records of 39 PTB patients who underwent IS due to absence of spontaneous sputum production between January 2011 and March 2014 at a tertiary hospital in South Korea were reviewed. Results of acid fast bacilli smear, Mycobacterium tuberculosis culture and polymerase chain reaction assay for M. tuberculosis (TB-PCR) of IS specimens from these patients were analyzed. Clinical and high-resolution computed tomography (HRCT) characteristics were also analyzed to find characteristics associated with IS culture positivity.

Results

Of the 39 IS specimens from PTB patients, 7 (17.9%) were smear positive and 31 (79.5%) were culture positive. Twenty-four IS specimens were tested for TB-PCR and 13 (54.2%) were positive on TB-PCR. Multivariate analysis showed that younger age (p=0.04) and presence of tree-in-bud appearance on HRCT (p=0.03) were independent predictors of IS culture positivity.

Conclusion

IS is useful for the diagnosis of PTB in adults unable to expectorate sputum. Younger age and tree-in-bud appearance on HRCT were associated with IS culture positivity in these patients.

High resolution computed tomography findings in smear-negative pulmonary tuberculosis patients according to their culture status

OBJECTIVE

The aim of this study was to assess the clinical features and high resolution computed tomography (HRCT) findings in smear-negative pulmonary tuberculosis (PTB) and to evaluate the correlation between these parameters and the culture results.

METHODS

We retrospectively studied 78 active smear-negative PTB patients. They were divided into two groups according to their culture results. The HRCT findings and clinical features at the beginning of the antituberculosis treatment were reviewed.

RESULTS

The mean age was 22.48±3.18 years. Micronodules (87%), large nodules (63%) and centrilobular nodules (62%) were the most common HRCT findings. HRCT findings were observed in the right upper (72%), left upper (56%), right lower (32%), and left lower lobes (29%). Cough (37%) and chest pain (32%) were the most frequent symptoms at presentation.

CONCLUSIONS

There were no significant differences in the HRCT findings and clinical features between the two groups. Thus, in cases of smear-negative and culture-negative PTB, the patient with compatible clinical and radiological features should be considered for tuberculosis treatment.

Evaluation of the relationship between smear positivity and high-resolution CT findings in children with pulmonary tuberculosis

Background

The aim of this study is to find a relationship between the radiological manifestations of childhood tuberculosis on a high-resolution computed tomography (HRCT) and the results of sputum smear. This study aims to propose an alternative indicator of infectivity in terms of prevention of disease transmission through selective isolation policy in children whose clinical condition is highly suggestive of tuberculosis.

Material/Methods

This retrospective comparative study was performed on 95 children under 15 years of age diagnosed with tuberculosis based on both WHO criteria and positive sputum culture for mycobacterium Tuberculosis. The children were admitted for TB screening in the pediatric department of national research institute of tuberculosis and lung disease (NRITLD) between 2008–2012. Direct smear collected from sputum or gastric lavage, as well as HRCT were performed in all children prior to administration of medical therapy. Children were divided into 2 groups based on positive and negative smear results. HRCT abnormalities, as well as their anatomical distribution were compared between these 2 groups using multivariate analytic model.

Results

The most prevalent abnormalities in the positive smear group were consolidation, tree-in-bud pattern, upper lobe nodular infiltration and cavitation. The negative smear group featured lymphadenopathy, consolidation, collapse and nodular infiltration in the upper lobe. Cavity, tree- in-bud pattern and upper lobe nodular infiltration were highly associated with smear positivity in children. Conversely, lymphadenopathy and collapse had significant association with a negative smear.

Conclusions

This study revealed that cavity, tree-in-bud and upper lobe nodular infiltration has significant association with smear positivity in childhood tuberculosis. On the other hand, lymphadenopathy and collapse were closely associated with smear negativity in this age group. It was also demonstrated that children with a positive smear most likely presented with radiological features of post primary tuberculosis, while the negative smear group most often manifested with primary tuberculosis.

Whole blood interferon-γ release assay is insufficient for the diagnosis of sputum smear negative pulmonary tuberculosis

PURPOSE

We investigated the value of an interferon-γ release assay (IGRA) for the diagnosis of active pulmonary tuberculosis (PTB) among sputum smear negative PTB suspects in an environment with intermediate burden of PTB and high Bacillus Calmette-Guerin (BCG) vaccination rate.

MATERIALS AND METHODS

We retrospectively reviewed IGRA, medical records, chest PA and CT scan of PTB suspects seen at Gangnam Severance Hospital, Seoul, Korea from Oct. 2007 to Apr. 2013. "Active PTB" was diagnosed when 1) M. tuberculosis culture positive, 2) confirmation by pathologic examination; or 3) clinical findings compatible with TB.

RESULTS

Of 224 sputum smear negative PTB suspects, 94 were confirmed as having active PTB. There were no statistically significant differences in the diagnostic yield of IGRA between immunocompromised and immunocompetent sputum smear negative PTB suspects. IGRA did show superior sensitivity [81.9%, 95% confidence interval (CI); 74.13-89.70%] in the diagnosis of sputum smear negative PTB when compared with chest high-resolution computed tomography (HRCT), tuberculin skin test (TST), and chest X-ray (p<0.001). Also, IGRA showed highest negative predictive value (82.7%, 95% CI; 75.16-90.15%) when compared with HRCT, TST and chest X-ray (p=0.023). However, combining the results of IGRA with those of HRCT, TST, or both did not increase any diagnostic parameters.

CONCLUSION

Failure to increase diagnostic yields by combination with other diagnostic modalities suggests that additional enforcement with IGRA may be insufficient to exclude other diagnoses in sputum smear negative PTB suspects and to screen active PTB in an environment with intermediate TB prevalence and a high BCG vaccination rate.

Cost effectiveness of high resolution computed tomography with interferon-gamma release assay for tuberculosis contact investigation

BACKGROUND

Tuberculosis contact investigation is one of the important public health strategies to control tuberculosis worldwide. Recently, high resolution computed tomography (HRCT) has been reported as a more accurate radiological method with higher sensitivity and specificity than chest X-ray (CXR) to detect active tuberculosis. In this study, we assessed the cost effectiveness of HRCT compared to CXR in combination with QuantiFERON(®)-TB Gold In-Tube (QFT) or the tuberculin skin test (TST) for tuberculosis contact investigation.

METHODS

We constructed Markov models using a societal perspective on the lifetime horizon. The target population was a hypothetical cohort of immunocompetent 20-year-old contacts with smear-positive tuberculosis patients in developed countries. Six strategies; QFT followed by CXR, QFT followed by HRCT, TST followed by CXR, TST followed by HRCT, CXR alone and HRCT alone were modeled. All costs and clinical benefits were discounted at a fixed annual rate of 3%.

RESULTS

In the base-case analysis, QFT followed by HRCT strategy yielded the greatest benefit at the lowest cost ($US 6308.65; 27.56045 quality-adjusted life-years [QALYs])[year 2012 values]. Cost-effectiveness was sensitive to BCG vaccination rate.

CONCLUSIONS

The QFT followed by HRCT strategy yielded the greatest benefits at the lowest cost. HRCT chest imaging, instead of CXR, is recommended as a cost effective addition to the evaluation and management of tuberculosis contacts in public health policy.

Fiberoptic bronchoscopy for the rapid diagnosis of smear-negative pulmonary tuberculosis

Background

This study was aimed to investigate the diagnostic value of fiberoptic bronchoscopy (FOB) with chest high-resolution computed tomography (HRCT) for the rapid diagnosis of active pulmonary tuberculosis (PTB) in patients suspected of PTB but found to have a negative sputum acid-fast bacilli (AFB) smear.

Methods

We evaluated the diagnostic accuracy of results from FOB and HRCT in 126 patients at Gangnam Severance Hospital (Seoul, Korea) who were suspected of having PTB.

Results

Of 126 patients who had negative sputum AFB smears but were suspected of having PTB, 54 patients were confirmed as having active PTB. Hemoptysis was negatively correlated with active PTB. Tree-in-bud appearance on HRCT was significantly associated with active PTB. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of FOB alone was 75.9%, 97.2%, 95.3%, and 84.3%, respectively, for the rapid diagnosis of active PTB. The combination of FOB and HRCT improved the sensitivity to 96.3% and the NPV to 96.2%.

Conclusions

FOB is a useful tool in the rapid diagnosis of active PTB with a high sensitivity, specificity, PPV and NPV in sputum smear-negative PTB-suspected patients. HRCT improves the sensitivity of FOB when used in combination with FOB in sputum smear-negative patients suspected of having PTB.

Changes in platelet count and indices in pulmonary tuberculosis

BACKGROUND

Recent studies show that platelets have important roles in the immune system. Little is known about the clinical significance of platelet indices. Changes in platelet indices, including platelet distribution width (PDW), mean platelet volume (MPV) and plateletcrit, in pulmonary tuberculosis were investigated.

METHODS

Platelet indices were quantified in 82 patients with active tuberculosis and 87 patients with inactive or non-tuberculous disease (controls). Radiological extent of the disease was assessed.

RESULTS

There were significantly higher PDW (40.9+/-23.5% vs. 27.0+/-14.5%), MPV (10.05+/-2.36 vs. 8.83+/-1.47 fL) and plateletcrit (0.330+/-0166% vs. 0.266+/-0.128%) values in the active tuberculosis group, which decreased significantly with anti-tuberculous therapy. Erythrocyte sedimentation rate and plateletcrit showed significant correlation (r=0.54 and r=0.66) with radiological extent of tuberculosis, while PDW and MPV correlations with radiological extent of tuberculosis were also significant but weaker (r=0.31 and r=0.23). In a subpopulation of controls with pneumonia, which leads to acute phase reaction, PDW, MPV and plateletcrit values were significantly lower than in the tuberculosis group.

CONCLUSIONS

We suggest that PDW, MPV and plateletcrit change in tuberculosis and that these changes may not reflect only acute phase reaction and disease activity. The potential role of platelet indices in tuberculosis immunopathogenesis remains to be investigated.

High-resolution CT findings in patients with pulmonary tuberculosis: correlation with the degree of smear positivity

BACKGROUND

There are data about the relationship between morphologic findings on high-resolution computed tomography (HRCT) and the number of acid-fast bacilli (AFB) on sputum smears in patients with pulmonary tuberculosis (PTB). It was also shown that existence of cavities and airspace consolidation might be related to smear positivity in PTB patients. However, there is no study suggesting a relationship between AFB on sputum smears and radiologic extent of disease based on HRCT findings.

AIM

In this study, we investigated a relationship between the degree of smear positivity and radiologic extent of disease based on HRCT findings and, the degree of smear positivity and different pulmonary parenchymal changes on HRCTs of the PTB patients.

METHODS

Sixty-one male patients with PTB (mean age: 22+/-3.2) were included into the study. HRCT images were assessed for patterns, distribution, and profusion of pulmonary abnormalities. Dividing the lungs into 3 zones, profusion of abnormalities was assessed. A profusion score was given. Patients were divided as smear positive and smear negative and compared for the scores of HRCT findings. Smear-positive patients were divided into 4 groups as per grading of the sputum AFB smear: group I (sputum 1+), group II (sputum 2+), group III (sputum 3+), and group IV (sputum 4+). Correlations were investigated between the degree of smear positivity and the scores of HRCT findings.

RESULTS

A significant correlation between radiologic extent of the disease based on HRCT and the degree of smear positivity was found (r=0.63, P=0.0001). There were also significant correlations between the degree of smear positivity and the scores of different HRCT findings. Nodule, cavity, and bronchial lesions are the most important contributors of the predictive properties of the total score. There was significant differences for the scores of HRCT findings between smear-positive and smear-negative patients.

CONCLUSIONS

Our study suggests that radiologic extent of disease based on HRCT findings in patients with PTB correlated with the degree of smear positivity. Different HRCT findings such as nodule, cavitation, ground-glass opacity, consolidation, and bronchial lesion are significantly associated with smear-positive PTB. Particularly, nodules, cavities, and bronchial lesions might be predictors of smear positivity in patients with PTB. This study also suggests that the thickness of cavity wall and the distance of cavity from central airways might be related to the degree of smear positivity.

Primary nasolacrymal tuberculosis diagnosed after dacryocytorhinostomy

Although tuberculosis (TB) is common and well recognized in many countries, unusual presentations of the disease sometimes raise difficulties in differential diagnosis. Primary tuberculosis of the lacrimal sac and the nasolacrimal duct is an extremely rare presentation of extra-pulmonary tuberculosis. Dacryocystorhinostomy alone is not sufficient for the treatment of these patients and an anti-tuberculous therapy has to be added. Here we present a patient with primary tuberculosis, which is limited to the inferior meatus and filled the entire lacrimal sac on the left side. The patient underwent endoscopic dacryocystorhinostomy due to obstruction of the nasolacrimal duct and culture of the granulation tissue, taken from the lacrimal sac revealed mycobacterial tuberculosis. The patient was improved with anti-tuberculous therapy that was added to the surgery. Primary tuberculosis is a rare granulomatous disease of the nasolacrimal system, which should be considered in the differential diagnosis to plan the effective treatment.