Low yield of chest radiography in a large tuberculosis screening program

Granulomatous Cheilitis or Tuberculid?

The granulomatous cheilitis (GC) presents a heterogeneous group of disorders characterised by a granulomatous inflammation/reaction of the lips to various stimuli. Numerous etiologies have been proposed, including genetic, immunologic, allergic and infectious. Among the secondary causes of GC, an infection by Mycobacterium tuberculosis (MBT) should be considered. In such cases, the GC could be the clinical presentation of a tuberculid resulting from a hypersensitivity reaction to an underlying focus of active (ATBI) or latent tuberculosis infection (LTBI). This communication describes an immunocompetent patient diagnosed with GC resulting from tuberculid, who responded well to Isoniazid monotherapy.

Chest computed tomography scan as an initial diagnostic method for tuberculosis infection detected by mass screening

BACKGROUND/AIMS

We assessed the diagnostic yield of chest computed tomography (CT) as an initial diagnostic method for patients with a tuberculosis (TB) infection detected by mass screening in a country with an intermediate TB burden.

METHODS

A retrospective study was conducted on patients with TB infection detected by mass screening performed between January 2015 and March 2018. The patients were classified according to whether they had a chest X-ray (CXR) or CT scan as an initial diagnostic test to exclude active TB.

RESULTS

Of 542 patients with TB infection detected by mass screening, 222 and 320 were initially examined by CXR and CT, respectively; the two modalities showed no significant difference in rate of detection of patients with active TB (0.9% and 2.5%, respectively; p = 0.110). However, chest CT was associated with further invasive tests using bronchoscopy and respiratory specimens, and significantly increased the frequency of hospital visits.

CONCLUSION

Chest CT was not supported as an initial diagnostic method to rule out active TB in patients with a TB infection detected by mass screening in a country with an intermediate TB burden.

Differentiating between active and latent tuberculosis with chest computed tomography

PURPOSE

The purpose of this study was to evaluate the capabilities of chest computed tomography (CT) in distinguishing between active and latent tuberculosis in patients positive for interferon-gamma release assay (IGRA) testing, and to compare the performance of CT with that of quantitative IGRA testing in a low incidence setting.

MATERIALS AND METHODS

Patients with latent or active tuberculosis define by an IGRA positive test were retrospectively recruited. Sensitivity, specificity and accuracy were determined for CT variables and quantitative IGRA results. Final diagnosis of active tuberculosis was based on clinical data and microbiological culture. Univariable and multivariable analyses were performed using logistic regression model to identify CT variables associated with the diagnosis of active tuberculosis.

RESULTS

A total of 92 patients with positive IGRA results who underwent CT examination were included. There were 54 men and 38 women with a mean age of 53.5±18 (SD) years (range: 40-68 years). Of them, 22 patients (24%) had positive Mycobacterium tuberculosis culture and 70 (76%) had latent tuberculosis. Among CT variables, consolidation had the greatest sensitivity (77%; 95%CI: 60-95%) and "tree-in-bud" the greatest specificity (97%; 95% CI: 93-100%) for the diagnosis of active tuberculosis. At univariable analysis "tree-in-bud", splenic calcification and non-calcified lung nodules were the significant variables independently associated with active tuberculosis. At multivariable analysis, the adjusted odds ratio of "tree-in-bud" was 42.91 (95% CI: 5.62-327.42). Using an optimal threshold of 51 spots, quantitative IGRA yielded 64% sensitivity (95% CI: 44-84%) and 61% specificity (95% CI: 50-73%) for the diagnosis of active tuberculosis.

CONCLUSIONS

In a low incidence setting, chest CT, especially when "tree-in-bud" pattern is present, is superior to quantitative IGRA testing to identify patients with active tuberculosis among those with positive IGRA testing.

Acquired Resistance to Isoniazid During Isoniazid Monotherapy in a Subject with Latent Infection Following Household Rifampicin-Resistant Tuberculosis Contact: A Case Report

Appropriate treatment is the key element in eliminating tuberculosis (TB), and requires prompt diagnosis. We presented a case of a household contact of rifampicin-resistant TB revealing reactive IFN-gamma release assay with unsuspicious clinical and radiologic examinations. She was diagnosed with latent tuberculosis infection (LTBI) and treated with isoniazid monotherapy. On the ninth month, she developed a progressive cough and was found to harbor active TB disease with added resistance to isoniazid. An individualized anti-TB regimen consisting of moxifloxacin, kanamycin, prothionamide, ethambutol, and pyrazinamide was prescribed for 20 months, leading to sputum culture conversion and improvement of the reported symptom. No recurrence was observed on one-year follow-up. Assuming high compliance to therapy, we propose that the patient may have been underdiagnosed and received sub-optimal treatment leading to acquired-drug resistance. Conventional diagnosis methods based on immunological assay and radiographical findings may be insufficient to distinguish the incipient and subclinical states of TB from LTBI.

Delayed Isolation of Active Pulmonary Tuberculosis in Hospitalized Patients: A Pivotal Role of Radiologic Evaluation

OBJECTIVE. The purpose of this study was to determine factors related to delayed isolation of patients hospitalized with active pulmonary tuberculosis (TB). MATERIALS AND METHODS. A total of 130 immunocompetent hospitalized patients with active pulmonary TB who had positive sputum culture results from January 2015 to December 2017 were reviewed. Delayed isolation of pulmonary TB was defined as failure to initiate airborne isolation within the first 3 days of hospitalization. Clinical and microbiologic characteristics of the patients and radiologic features on chest radiography (n = 130) and chest CT (n = 118) were retrospectively reviewed. Findings were compared between patients with early isolation and those with delayed isolation. Univariate and multivariate analyses were performed to determine independent predictors of delayed isolation. RESULTS. Forty-four patients (34%) had delayed isolation after initial hospitalization. On univariate and multivariate analyses, atypical presentation of active pulmonary TB on CT (odds ratio, 7.203; 95% CI, 2.203-23.551; p = 0.001) and concurrent lung parenchymal diseases on CT (odds ratio, 14.605; 95% CI, 3.274-65.155; p < 0.001) were significant predictors of delayed isolation of patients with active pulmonary TB. CONCLUSION. Awareness of the factors related to delayed diagnosis of active pulmonary TB is important to avoid an unexpected in-hospital outbreak of TB and control the disease. Atypical presentation of active pulmonary TB and concurrent lung parenchymal diseases on CT are significant factors related to delayed isolation of hospitalized patients with active pulmonary TB.

Review of Evidence for Using Chest X-Rays for Active Tuberculosis Screening in Long-Term Care in Canada

Background: People living in long-term care facilities (LTCF) are at high risk to develop active tuberculosis primarily as a result of reactivation of a latent TB infection, or endemic transmission between residents. Current national guidelines in Canada are to use a posterior-anterior and lateral chest X-ray to screen for TB for those over 65 years old, upon admission to a LTCF.

Objective: To assess the available evidence for cost benefits of universal chest X-ray screening for new LTCF residents.

Methodology: We conducted a search for all articles published until September 2018, in PubMed and WorlCat databases, in English, using a combination of key words: chest X-ray, chest radiography or CXR, long-term care, elderly, screening, and tuberculosis. We also reviewed publicly available guidelines for screening new residents to LTCF from across Canada. We report on a qualitative synthesis of the evidence in the documents retrieved.

Results: The final review yielded four cost-effectiveness studies (2 of 4 conducted in countries with low incidence), one systematic review, one recommendation/editorial, and one cohort study. We found that in a tuberculosis low-incidence country the CXR cost per identified case was $672,298 CAD. Enacting a more targeted screening program, perhaps one that tests only those who previously had TB, or other high-risk medical conditions may enhance the cost-effectiveness.

Recommendations: We suggest reviewing the screening policy for active TB in people entering LTCF, which is based on a CXR. The results indicate that a targeted search for active TB in people with symptoms or other high-risk medical conditions may be more cost-effective.

Developing and verifying automatic detection of active pulmonary tuberculosis from multi-slice spiral CT images based on deep learning

OBJECTIVE

Diagnosis of tuberculosis (TB) in multi-slice spiral computed tomography (CT) images is a difficult task in many TB prevalent locations in which experienced radiologists are lacking. To address this difficulty, we develop an automated detection system based on artificial intelligence (AI) in this study to simplify the diagnostic process of active tuberculosis (ATB) and improve the diagnostic accuracy using CT images.

DATA

A CT image dataset of 846 patients is retrospectively collected from a large teaching hospital. The gold standard for ATB patients is sputum smear, and the gold standard for normal and pneumonia patients is the CT report result. The dataset is divided into independent training and testing data subsets. The training data contains 337 ATB, 110 pneumonia, and 120 normal cases, while the testing data contains 139 ATB, 40 pneumonia, and 100 normal cases, respectively.

METHODS

A U-Net deep learning algorithm was applied for automatic detection and segmentation of ATB lesions. Image processing methods are then applied to CT layers diagnosed as ATB lesions by U-Net, which can detect potentially misdiagnosed layers, and can turn 2D ATB lesions into 3D lesions based on consecutive U-Net annotations. Finally, independent test data is used to evaluate the performance of the developed AI tool.

RESULTS

For an independent test, the AI tool yields an AUC value of 0.980. Accuracy, sensitivity, specificity, positive predictive value, and negative predictive value are 0.968, 0.964, 0.971, 0.971, and 0.964, respectively, which shows that the AI tool performs well for detection of ATB and differential diagnosis of non-ATB (i.e. pneumonia and normal cases).

CONCLUSION

An AI tool for automatic detection of ATB in chest CT is successfully developed in this study. The AI tool can accurately detect ATB patients, and distinguish between ATB and non- ATB cases, which simplifies the diagnosis process and lays a solid foundation for the next step of AI in CT diagnosis of ATB in clinical application.

Radiological Signs of Latent Tuberculosis on Chest Radiography: A Systematic Review and Meta-Analysis

Objective

Current guidelines recommend screening for latent tuberculosis infection (LTBI) with a tuberculin skin test (TST) or interferon gamma release assay (IGRA), or both. Many also recommend chest radiography (CXR), although its added value is uncertain. This systematic review assessed the prevalence of abnormalities suggestive of LTBI on CXR (LTBI-CXR lesions) and evaluated the strength of the association.

Method

We searched 4 databases up to September 2017 and systematically reviewed cross-sectional and cohort studies reporting LTBI-CXR lesions in individuals with a positive TST or IGRA, or both, result. Prevalence estimates were pooled using random effects models and odds ratios (ORs) were used to calculate risk estimates.

Results

In the 26 included studies, the pooled proportion of individuals with LTBI having LTBI-CXR lesions was 0.15 (95% confidence interval [CI], 0.12–0.18]. In 16 studies that reported on individuals with LTBI and uninfected controls, LTBI-CXR lesions were associated with a positive TST result ≥ 5 mm or ≥ 10 mm (OR, 2.45; 95% CI, 1.00–5.99; and OR, 2.06; 95% CI, 1.38–3.09, respectively) and with a positive QuantiFERON result (OR, 1.99; 95% CI, 1.17–3.39) compared to CXR in uninfected controls. Although few studies reported specified lesions, calcified nodules were most frequently reported in individuals with LTBI (proportion, 0.07; 95% CI, 0.02–0.11).

Conclusions

Lesions on CXR suggestive of previous infection with Mycobacterium tuberculosis were significantly associated with positive tests for LTBI, although the sensitivity was only 15%. This finding may have added value when detection of past LTBI is important but immunodiagnostic tests may be unreliable.

Abnormalities suggestive of latent tuberculosis infection on chest radiography; how specific are they?

Background

Several radiological features have been reported in association with latent tuberculosis infection (LTBI) but it has not been studied which are specific. The aim of this study was to evaluate allegedly characteristic abnormalities on chest radiography (CXR) in patients with LTBI compared to uninfected controls.

Methods

From 236 patients tested with QuantiFERON-TB Gold In-Tube (QFT), the CXR was re-evaluated in a blinded fashion for fibrotic scarring, (non-)calcified nodules and pleural thickening. LTBI was defined as presence of a positive QFT result and/or positive tuberculin skin test result stratified by Bacille Calmette-Guérin-vaccination status.

Results

Any predefined abnormality of LTBI was observed in 116/236 (49.2%) patients, the frequency not being different between groups. However, the specificity for LTBI of a fibrotic scar ≥ 2 cm² was 100% [95% CI: 92.0%–100%] and of a calcified nodule ≥1.5 mm was 95.7% [95% CI: 85.2%–99.5%]. The frequency of non-calcified nodules and pleural thickening did not differ between groups.

Conclusion

Only a fibrotic scar ≥ 2 cm² and/or a calcified nodule ≥1.5 mm were significantly associated with LTBI. This finding is clinically relevant mainly in patients who are at significant risk of TB reactivation and in whom indirect diagnostic tests may be unreliable.

Nationwide surveillance algorithms for tuberculosis among immigrant workers from highly endemic countries following pre-entry screening in Taiwan

Background

This cross-sectional study was retrospectively performed to assess the trend of tuberculosis (TB) among Taiwan’s immigrant workers from highly TB-endemic countries under an intervention of conducting a 4-round follow-up (at 0–3 days and 6, 18, and 30 months post-migration) screening program with initial chest X-ray (CXR) following an overseas, pre-entry normal CXR.

Methods

The immigrant workers with TB disease enrolled in the Taiwan TB registry database in 2011–2014 were analyzed and linked to an immigrant worker physical exam database to stratify TB case categories of actively screened or not for comparison.

Results

Following pre-entry screening for the admission of CXR-normal immigrant workers from highly endemic countries, the overall TB incidence of 70.6–128.6/100,000 person-years resulted either from a subsequent series of 4-round post-entry active screenings or misalliance algorithms, including passive diagnostics for the illness. Overall, the TB relative risk based on incidence in the immigrant working population was 2.2- to 5.5-fold greater than that among corresponding age Taiwanese, with 14.3% (15.5/100,000 person-years) sputum-smear-positive pulmonary TB (SS+ PTB), 74.2% (80.8/100,000 person-years) sputum-smear-negative (SS-) PTB, and 7.8% (8.5/100,000 person-years) only extra-pulmonary TB (EPTB). Regarding the clinical characteristics, 55.5% TB cases – identified through passive illness diagnostics vs. 44.5% TB cases actively identified through mandatory screenings, were higher in SS+ PTB (adjusted odds Ratio (aOR): 1.5, 95% CI: 1.1–2.0, P = 0.008), higher in SC+ PTB (aOR: 1.4, 95% CI: 1.1–1.7, P = 0.004), higher in concurrent extra-pulmonary TB (aOR: 8.9, CI: 4.5–7.4, P < 0.001), and higher in normal CXR TB (aOR: > 100, CI: 0- > 100, P = 0.908). The TB yields of 3rd- to 4th-round screenings were higher than those of 1st- and 2nd-round screenings and ranged from 52.6–65.3 cases per 100,000 screenings in 2013–2014.

Conclusions

The multiple post-entry TB screenings with initial CXR for high-risk immigrants could actively reduce TB transmission by finding SS- TB cases at early stages. The TB yields at post-entry 3rd- to 4th-round screenings might imply a persistent reactivation of latent TB. Adding more sensitive, economical screenings and preventive treatments for latent TB infection is a comprehensive approach for accelerating TB elimination.

ACR Appropriateness Criteria® Imaging of Possible Tuberculosis

Pulmonary tuberculosis remains a major cause of disease worldwide and an important public health hazard in the United States. The imaging evaluation depends to a large degree on clinical symptoms and whether active disease is suspected or a subject is at high risk for developing active disease. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Incidence of Active Tuberculosis and Cohort Retention Among Adolescents in Western Kenya

SETTING

Siaya County, with the highest tuberculosis notification rates in Kenya.

OBJECTIVES

To determine the incidence of active tuberculosis and 1-year cohort retention in 12-18-year-old adolescents, in preparation for phase III tuberculosis vaccine trials.

METHODS

Adolescents were enrolled and followed up for 1-2 years to determine tuberculosis incidence. Adolescents with a positive tuberculin skin test, history of cohabitation with a tuberculosis case or at least 1 tuberculosis symptom received clinical and sputum examination and a chest radiograph. Definite tuberculosis cases were bacteriologically confirmed and clinical cases diagnosed by a clinician based on a suggestive chest radiograph and having clinical symptoms. Risk factors were explored using Poisson regression.

RESULTS

Among 4934 adolescents without tuberculosis at baseline, 26 tuberculosis cases were identified during follow-up with a corresponding incidence density of 4.4 [95% confidence interval (CI): 3.0-6.4] events per 1000 person-years of observation, 12 definite tuberculosis cases; incidence density of 2.0 (95% CI: 0.9-3.1). Having previous tuberculosis (rate ratio: 12.5; CI: 1.8-100) and presence of tuberculin skin test conversion (rate ratio: 3.4; CI: 1.5-7.7) were significantly associated with higher risk of tuberculosis. Overall (4086/4925), 83.0% of adolescents were retained in the study after 1 year of follow-up. Being female, older, out of school and being orphaned were significant risk factors for loss to follow-up.

CONCLUSION

The tuberculosis incidence in adolescents will help inform future tuberculosis vaccine trial sample size calculations for this setting. The predictive factors for tuberculosis and retention can be further explored in future trials.

Imaging of thoracic tuberculosis in children: current and future directions

Tuberculosis continues to be an important cause of morbidity and mortality worldwide. It is the leading cause of infection-related deaths worldwide. Children are amongst the high-risk groups for developing tuberculosis and often pose a challenge to the clinicians in making a definitive diagnosis. The newly released global tuberculosis report from World Health Organization reveals a 50% increase in fatality from tuberculosis in children. Significantly, diagnostic and treatment algorithms of tuberculosis for children differ from those of adults. Bacteriologic confirmation of the disease is often difficult in children; hence radiologists have an important role to play in early diagnosis of this disease. Despite advancing technology, the key diagnostic imaging modalities for primary care and emergency services, especially in rural and low-resource areas, are chest radiography and ultrasonography. In this article, we discuss various diagnostic imaging modalities used in diagnosis and treatment of tuberculosis and their indications. We highlight the use of US as point-of-care service along with mediastinal US and rapid MRI protocols, especially in mediastinal lymphadenopathy and thoracic complications. MRI is the ideal modality in high-resource areas when adequate infrastructure is available. Because the prevalence of tuberculosis is highest in lower-resource countries, we also discuss global initiatives in low-resource settings.

Low Yield of Chest Radiography in General Inpatients and Outpatients with "Positive PPD" Results in a Country with Low Prevalence of TB

RATIONALE AND OBJECTIVES

The purpose of this study was to assess the frequency and spectrum of abnormalities on routine screening chest radiographs among inpatients and outpatients with "positive purified protein derivative (PPD)" in a large tertiary care academic medical center in a country with low prevalence of tuberculosis (TB).

MATERIALS AND METHODS

The reports of all chest radiographs of general inpatients and outpatients referred for positive PPD (2010-2014) were evaluated for the frequency of evidence of active or latent TB and the spectrum of imaging findings. The results of additional chest radiographs and computed tomography scans were recorded, as were additional relevant clinical histories and symptoms.

RESULTS

Of the 2518 patients who underwent chest radiography for positive PPD, the radiographs were normal in 91.3%. The vast majority of the abnormal radiographs demonstrated findings consistent with old tuberculous disease. There were three cases (0.1%) of active TB, all of which were either recent immigrants from an endemic area or had other relevant histories or clinical symptoms suggestive of the disease.

CONCLUSIONS

Universal chest radiography in general inpatient and outpatient populations referred for positive PPD is of low yield for detecting active disease in a country with low prevalence of TB.

Use of low-dose computed tomography to assess pulmonary tuberculosis among healthcare workers in a tuberculosis hospital

Background

According to the World Health Organization, China is one of 22 countries with serious tuberculosis (TB) infections and one of the 27 countries with serious multidrug-resistant TB strains. Despite the decline of tuberculosis in the overall population, healthcare workers (HCWs) are still at a high risk of infection. Compared with high-income countries, the TB prevalence among HCWs is higher in low- and middle-income countries. Low-dose computed tomography (LDCT) is becoming more popular due to its superior sensitivity and lower radiation dose. However, there have been no reports about active pulmonary tuberculosis (PTB) among HCWs as assessed with LDCT. The purposes of this study were to examine PTB statuses in HCWs in hospitals specializing in TB treatment and explore the significance of the application of LDCT to these workers.

Methods

This study retrospectively analysed the physical examination data of healthcare workers in the Beijing Chest Hospital from September 2012 to December 2015. Low-dose lung CT examinations were performed in all cases. The comparisons between active and inactive PTB according to the CT findings were made using the Pearson chi-square test or the Fisher’s exact test. Comparisons between the incidences of active PTB in high-risk areas and non-high-risk areas were performed using the Pearson chi-square test. Analyses of active PTB were performed according to different ages, numbers of years on the job, and the risks of the working areas. Active PTB as diagnosed by the LDCT examinations alone was compared with the final comprehensive diagnoses, and the sensitivity and positive predictive value were calculated.

Results

A total of 1 012 participants were included in this study. During the 4-year period of medical examinations, active PTB was found in 19 cases, and inactive PTB was found in 109 cases. The prevalence of active PTB in the participants was 1.24%, 0.67%, 0.81%, and 0.53% for years 2012 to 2015. The corresponding incidences of active PTB among the tuberculosis hospital participants were 0.86%, 0.41%, 0.54%, and 0.26%. Most HCWs with active TB (78.9%, 15/19) worked in the high-risk areas of the hospital. There was a significant difference in the incidences of active PTB between the HCWs who worked in the high-risk and non-high-risk areas (odds ratio [OR], 14.415; 95% confidence interval (CI): 4.733 – 43.896). Comparisons of the CT signs between the active and inactive groups via chi-square tests revealed that the tree-in-bud, cavity, fibrous shadow, and calcification signs exhibited significant differences (P = 0.000, 0.021, 0.001, and 0.024, respectively). Tree-in-bud and cavity opacities suggest active pulmonary tuberculosis, whereas fibrous shadow and calcification opacities are the main features of inactive pulmonary tuberculosis. Comparison with the final comprehensive diagnoses revealed that the sensitivity and positive predictive value of the diagnoses of active PTB based on LDCT alone were 100% and 86.4%, respectively.

Conclusions

Healthcare workers in tuberculosis hospitals are a high-risk group for active PTB. Yearly LDCT examinations of such high-risk groups are feasible and necessary.

Electronic supplementary material

The online version of this article (doi:10.1186/s40249-017-0274-6) contains supplementary material, which is available to authorized users.

Tuberculin Skin Test Conversion among Individuals with Human Immunodeficiency Virus Infection on Antiretroviral Therapy in a Referral Teaching Hospital, Tehran, Iran

BACKGROUND

The risk of tuberculosis (TB) is greater for individuals with human immunodeficiency virus (HIV) who are on combined antiretroviral therapy (c-ART) than for the normal population. Therefore, the detection and treatment of latent tuberculosis infections is recommended for all HIV-positive persons with positive tuberculin skin tests (TSTs).

MATERIALS AND METHODS

This retrospective cohort study included all HIV-positive individuals with CD4 lymphocyte counts greater than 200 cells/μL and negative TST results, who were taking antiretroviral drugs and had been referred to Imam Khomeini Teaching Hospital Consultation Centre for Clients with Risky Behaviors in Tehran, Iran, from 2008 to 2013. TST conversion to positivity is defined as an induration increase of at least 5 mm compared with a previously negative TST result within a 1-year period. Conversion rates are expressed in person-years of observation.

RESULTS

A total of 113 patients were included in our study. At 1 year, 9 of the 113 TST-negative patients taking c-ART became TST-positive (8%; 8 males and 1 female). The TST conversion incidence rate was 10.09/100 person-years. TST conversion was only found to be associated with sex (odds ratio: 8.64; 95% confidence interval: 1.04-7.56, p = 0.032).

CONCLUSION

Our results suggest that TSTs should be administered to all HIV-positive patients before beginning isoniazid preventive therapy in Iran.

Tuberculosis screening using IGRA and chest computed tomography in patients with inflammatory bowel disease: A retrospective study

OBJECTIVES

To assess the prevalence and potential risk factors of latent tuberculosis infection (LTBI) in Chinese patients with inflammatory bowel disease (IBD) and to evaluate the role of chest computed tomography (CT) in the screening of LTBI.

METHODS

A single-center retrospective study was conducted and all IBD patients who had been screened for LTBI by T-SPOT.TB between December 2011 and January 2016 were enrolled in the study. Both inpatient and outpatient records were collected and comprehensively reviewed.

RESULTS

Altogether 534 IBD patients were included. The positivity rate of T-SPOT.TB was 18.0% overall, 31.9% in IBD unclassified, 22.5% in ulcerative colitis and 13.0% in Crohn's disease patients, respectively. Age, history of TB and the administration of immunosuppressants were significantly associated with T-SPOT.TB positivity. Among 123 patients who underwent serial testing, the conversion and reversion rate of T-SPOT.TB was 10.2% and 42.9%, respectively. Furthermore, 102 of 447 (22.8%) patients who underwent chest computed tomography (CT) were found with abnormal CT findings suggestive of LTBI. The concordance rate was 75% between the T-SPOT.TB and chest CT with a kappa value of 0.25 (95% CI 0.15-0.35).

CONCLUSIONS

The prevalence of LTBI in IBD patients is high in China. Chest CT is recommended as an alternative to IGRA for screening LTBI of IBD patients before commencing immunosuppressive therapy in high-prevalence regions.

Evaluation of Chest X-ray and Thoracic Computed Tomography in Patients with Suspected Tuberculosis

OBJECTIVE

To investigate if there is any correlation between positive findings detected by posterior-anterior (PA) chest radiograph and thoracic computerized tomography (CT) in cases with suspected lung tuberculosis (TB) due to positive tuberculin skin test (TST) results.

METHODS

This is a retrospective evaluation of the medical files of patients who visited the Department of Pediatrics, Istanbul University, Istanbul Faculty of Medicine from 2006, through 2011 as outpatients and had positive TST (>15 mm) results.

RESULTS

A total of 326 patients were included in the study; 45.7 % (n = 149) were girls, and the mean age was 9.0 ± 4.1 y (range: 1-17 y). In total, 14.4 % (n = 47) had TB findings, all of which were in the form of hilar lymphadenopathy. Among the 47 cases with TB findings in PA chest X-ray, 45 (95.7 %) also had findings in thoracic CT. Only 2 (4.3 %) patients had normal thoracic CT results although their PA chest X-ray results were positive.

CONCLUSIONS

Evaluation for pulmonary TB in children with positive isolated TSTs should be made primarily with PA chest X-ray. A routine thoracic CT scan is not necessary for asymptomatic patients with only hilar lymphadenopathy findings in PA chest radiographs.

Implementation of latent tuberculosis screening in HIV care centres: evaluation in a low tuberculosis incidence setting

The screening and treatment of latent tuberculosis infection (LTBI) to prevent active tuberculosis (TB) is recommended by the WHO in all HIV-infected patients. The aim of this study was to evaluate its implementation within Belgium's HIV care. A multiple-choice questionnaire was sent to 55 physicians working in the country's AIDS reference centres. Response rate reached 62%. Only 20% screened all their HIV-infected patients for LTBI. Screening methods used and their interpretation vary from one physician to another. The main barriers to the implementation of LTBI screening and treatment, as perceived by the participants, are lack of sensitivity of screening tools, risks associated with polypharmacy and toxicity of treatment. The poor coverage of LTBI screening reported here and the inconsistency in methods used raises concern. However, this was not unexpected as, in low-TB incidence countries, who, when and how to screen for LTBI remains unclear and published guidelines show important disparities. Recently, a targeted approach in which only HIV-infected patients at highest risk of TB are screened has been suggested. Such a strategy would limit unnecessary exposure to LTBI treatment. This methodology was approved by 80% of the participants and could therefore achieve greater coverage. Its clinical validation is still pending.

Using Spatial Disease Patterns and Patient-Level Characteristics to Describe Prevalence Elastic Behavior in Treatment for Latent Tuberculosis Infection (LTBI)

OBJECTIVE

Individual adherence to a 9-month regimen of isoniazid (9INH) for treatment of latent tuberculosis infection (LTBI) was hypothesized to reflect a prevalent elastic health behavior pattern, or prevention behavior correlated with relevant disease burden.

METHOD

Log-rank tests were used to compare survival functions among raw prevalence tertiles for diseases including TB, diabetes, and obesity. Own and cross-prevalence elasticities were calculated and spatially characterized behavioral response to diseases that may impact TB re-infection and/or re-activation. Discrete choice models were used to assess the significance of the spatial elasticities among an ethnically diverse clinic population of 552 patients in an urban American county in 2010.

RESULTS

Log-rank results revealed a statistical association between dropout and chronic disease prevalence (p < .01), but not TB prevalence (p = .13). Discrete choice models incorporating spatial elasticities and controlling for patient- and treatment-level characteristics demonstrated significant associations with adherence (p < .01), an effect robust to various alternative treatment definitions.

CONCLUSION

Individual LTBI adherence tracks a prevalence elastic pattern that may represent a potential risk for re-infection and re-activation.

IGRA as a predictive factor of silent pulmonary changes in individuals following exposure to tuberculosis

OBJECTIVES

We conducted a study on usefulness of the tuberculin skin test (TST) and the Quantiferon-TB Gold IT (QFT) tests as predictors of radiological changes after contact with tuberculosis.

MATERIALS AND METHODS

The study group consisted of TB-exposed HCWs working in the Military Institute of Medicine (Warsaw, Poland). The usefulness of TST, QFT, and a combination of both tests was assessed for prediction of silent radiological findings.

RESULTS

83 previously TB-exposed participants were recruited. None of the participants had a history of active tuberculosis. Positive TST results were reported in 72 (86.8 %) participants, and positive QFTs were observed in 27 (32.5 %) cases. Chest radiographs revealed 23 findings specific for non-active tuberculosis in 18 (21.7 %) participants. The results of the QFTs were associated with the highest negative predictive value, positive predictive value, and positive likelihood ratio of silent chest X-ray findings suggestive of latent tuberculosis infection. Positive QFT was the only statistically significant variable that increases the odds ratio (OR-8.3) of the presence of typical of tuberculosis radiological changes in the lung.

CONCLUSION

A positive QFT result in an individual with no TB history who was exposed to tuberculosis in the past is associated with a significantly higher risk of clinically silent parenchymal lesions in lungs suggestive of previous tuberculosis.

To x-ray or not to x-ray? Screening asymptomatic children for pulmonary TB: a retrospective audit

OBJECTIVE

Recent studies found that a chest x-ray (CXR) has limited value in the assessment of asymptomatic adults with tuberculosis (TB) infection. We aimed to determine in asymptomatic children with a positive tuberculin skin test and/or interferon-γ release assay (TST/IGRA) whether a CXR identifies findings suggestive of pulmonary TB.

DESIGN, SETTING AND PATIENTS

All children with TB infection (defined as TST ≥10 mm and/or positive IGRA) presenting to The Royal Children's Hospital Melbourne during a 54-month period were included. All CXRs were reviewed by a senior radiologist blinded to the clinical details. The medical records of those with radiological abnormalities suggestive of TB were examined to identify those who were asymptomatic when the CXR was done. Demographical data were also collected.

RESULTS

CXRs were available for 268 of 330 TB-infected children, of whom 60 had CXR findings suggestive of TB. Of the 57 for whom clinical details were available, 26 were asymptomatic. Of these asymptomatic children with radiological abnormalities suggestive of TB, 6 had CXR findings suggestive of active TB, 14 had CXR findings suggestive of prior TB and 6 had isolated non-calcified hilar lymphadenopathy. The six with findings suggestive of active TB represented 2.6% (95% CI 0.9 to 5.5%) of asymptomatic TST/IGRA-positive children with evaluable CXRs. One child with isolated hilar lymphadenopathy had microbiologically-confirmed TB.

CONCLUSIONS

In contrast to the results from studies in adults, a CXR identified a small but noteworthy number of children with findings suggestive of pulmonary TB in the absence of clinical symptoms.

Immunosuppression Adversely Affects TST but Not IGRAs in Patients with Psoriasis or Inflammatory Musculoskeletal Diseases

The performance of the interferon gamma release assays (IGRAs) and tuberculin skin test (TST) was reviewed retrospectively in patients with psoriasis, inflammatory musculoskeletal diseases, or miscellaneous inflammatory conditions. The study was carried out over a 22-month period using 109 records of patients with psoriasis (n = 21), musculoskeletal disease (n = 74), or other inflammatory conditions (n = 14). Forty-four (48%) of 109 patients were on immunosuppressive therapy and 38/109 (35%) on systemic glucocorticoid therapy. The agreement between the IGRAs was substantial (κ = 0.71) whilst that between the IGRAs and TST was low (κ = 0.32). Logistic regression models revealed that IGRAs associated with risk factors for latent tuberculosis infection better than TST. TST was influenced by age, BCG vaccination, sex, and glucocorticoid therapy. We found that IGRAs performed equally well with low level of indeterminate results (1-2%). IGRAs were superior to TST because the latter was influenced by BCG-vaccination status and immunosuppressive therapy.

Tuberculous Spondylitis Presenting as Severe Chest Pain

This case report describes a 32-year-old male who presented to an emergency department with severe chest pain and a history of cough, fever, night sweats, loss of appetite and weight. Chest radiography revealed a left upper lobe consolidation and multiple compression deformities in the thoracic spine. Magnetic resonance imaging demonstrated significant kyphosis and vertebral plana at two thoracic levels. Anterior compression of the spinal cord and adjacent soft tissue masses were also noted.

Redefining latent tuberculosis

TB remains a public health problem worldwide, in part due to latent TB infection that serves as a global reservoir of potential disease. In the 20th century, the natural history of TB was defined by clinical symptoms, the tuberculin skin test and chest x-ray. The last decade witnessed the invention and application of IFN-γ release assays and newer immunological tools that enabled a re-appraisal of the natural history of TB. Here, we review the conventional understanding of latent TB and recount how immunology has redefined latent TB as a spectrum of pathogen burden and host immune control. We discuss recent and future advances in the fields of TB immunology and diagnostics that will improve public health strategies to control TB.