Chest computed tomography is more likely to show latent tuberculosis foci than simple chest radiography in liver transplant candidates

CT in the detection of latent tuberculosis: a systematic review

AIM

To evaluate the use of computed tomography (CT) and low-dose CT in the detection of latent tuberculosis (TB).

MATERIALS AND METHODS

A systematic search of literature in adherence with the PRISMA guidelines was carried out. Quality assessment of the included studies was conducted.

RESULTS

The search strategy identified a total of 4,621 studies. Sixteen studies were considered eligible and included in the review. There was high heterogeneity among all studies. CT was identified as much more sensitive for the detection of latent TB in all studies despite chest radiography often being recommended in guidelines to assess patients for latent TB. Low-dose CT showed promising results in four of the studies; however, these results were limited due to small sample sizes.

CONCLUSION

CT is much superior to chest radiography consistently identifying additional cases of latent TB. There are limited high-quality publications available using low-dose CT but findings thus far suggest low-dose CT could be used as an alternative to standard-dose CT for the detection of latent TB. It is recommended that a randomised controlled trial investigating low-dose CT should be carried out.

Mycobacteria in Organ Transplant Recipients

This review describes the epidemiology and risk factors of tuberculosis (TB) in solid organ transplant recipients. We discuss the pre-transplant screening for risk of TB and management of latent TB in this population. We also discuss the challenges of management of TB and other difficult to treat mycobacteria such as Mycobacterium abscessus and Mycobacterium avium complex. The drugs for the management of these infections include rifamycins which have significant drug interactions with immunosuppressants and must be monitored closely.

The cascade of care in testing and treatment of latent tuberculosis infection in liver transplant candidates

BACKGROUND

Testing and treatment for latent tuberculosis infection (LTBI) can mitigate risk of active tuberculosis (TB) post-liver transplant (LT). Testing and treatment completion rates have been reported low in this population. Our study aims to quantify the proportion of LT candidates who completed LTBI care cascade in our center.

METHODS

A retrospective chart review was conducted on LT candidates from 2012 to 2021. Primary outcome was the proportion of patients who completed each cascade stage. Secondary outcome was an analysis of factors associated with positive and indeterminate LTBI testing.

RESULTS

Of the 273 LT candidates, 265 (97.1%) were referred to transplant infectious disease (TID), 264 (96.7%) had orders for interferon-gamma release assay (IGRA), 262 (96%) underwent TID evaluation, and 259 (94.9%) completed IGRA. Twenty had LTBI, and 18 were treatment naïve and recommended for treatment. Of the 18, 15 (83.3%) agreed to therapy, 14 (77.8%) initiated treatment, and 12 (66.7%) completed treatment. No posttransplant TB reactivation occurred. Patients born in Asia, previous incarceration, past military service, and granuloma findings on chest imaging were likely to have positive IGRA (p < .05). Older age and travel to TB-endemic countries were likely to have indeterminate IGRA (p < .05). Indeterminate IGRAs were more common in QuantiFERON (QTF)-Gold Plus TB (15.3%) versus QTF-Gold TB (9.3%, p < .001).

CONCLUSIONS

High rates of LTBI testing and treatment initiation and completion can be attributed to a standardized process that includes TID evaluation. Future studies in larger cohort are needed to better understand factors that can optimize the completion rates of LTBI treatment in LT candidates.

Correlation between tuberculosis-specific interferon-γ release assay and intrathoracic calcification: A cross-sectional study

Background

Although persistent tuberculosis (TB) infection is known to cause calcification in the lungs, the relationship between intrathoracic calcification and the results of the interferon-γ release assay (IGRA) has not been fully elucidated. This study aimed to assess the association between intrathoracic calcification and IGRA results.

Methods

We retrospectively included consecutive patients who concurrently underwent chest X-ray, chest computed tomography (CT), and an IGRA. Patients with a current diagnosis of active TB or treatment history of active TB or latent tuberculosis infection (LTBI) were excluded. The association between calcification according to the chest X-ray or CT and IGRA results were analyzed using binomial logistic regression.

Results

This study included 574 patients, and 38 (7%) patients had a positive IGRA result. Patients with a positive result were significantly older and had a higher proportion of comorbidities, and history of tuberculosis exposure compared to those with a negative result. Calcification of the lung field and mediastinal lymph nodes according to chest CT was more frequently observed in patients with a positive IGRA result, whereas no significant difference was observed concerning the proportion of lung field calcification on chest X-ray between patients with positive and negative IGRA results. In multivariate analysis, calcification of mediastinal lymph nodes alone (adjusted odds ratio [OR] = 3.82, 95% confidence interval [CI] = 1.76–8.26) and the combination of lung field and mediastinal lymph node calcification (adjusted OR = 4.12, 95% CI = 1.51–11.76) on chest CT was independently associated with positive IGRA results.

Conclusions

The finding of mediastinal lymph node calcification, with or without lung field calcification, on chest CT was associated with positive IGRA results independent of TB exposure history. Previous TB infection including eliminated TB infection and LTBI can be suspected when calcified lymph nodes in are observed the mediastinum on chest CT.

Review article: latent tuberculosis in patients with inflammatory bowel diseases receiving immunosuppression-risks, screening, diagnosis and management

BACKGROUND

One quarter of the world's population has latent tuberculosis infection (LTBI). Systemic immunosuppression is a risk factor for LTBI reactivation and the development of active tuberculosis. Such reactivation carries a risk of significant morbidity and mortality. Despite the increasing global incidence of inflammatory bowel disease (IBD) and the use of immune-based therapies, current guidelines on the testing and treatment of LTBI in patients with IBD are haphazard with a paucity of evidence.

AIM

To review the screening, diagnostic practices and medical management of LTBI in patients with IBD.

METHODS

Published literature was reviewed, and recommendations for testing and treatment were synthesised by experts in both infectious diseases and IBD.

RESULTS

Screening for LTBI should be performed proactively and includes assessment of risk factors, an interferon-gamma releasing assay or tuberculin skin test and chest X-ray. LTBI treatment in patients with IBD is scenario-dependent, related to geographical endemicity, travel and other factors. Ideally, LTBI therapy should be used prior to immune suppression but can be applied concurrently where urgent IBD medical treatment is required. Management is best directed by a multidisciplinary team involving gastroenterologists, infectious diseases specialists and pharmacists. Ongoing surveillance is recommended during therapy. Newer LTBI therapies show promise, but medication interactions need to be considered. There are major gaps in evidence, particularly with specific newer therapeutic approaches to IBD.

CONCLUSIONS

Proactive screening for LTBI is essential in patients with IBD undergoing immune-suppressing therapy and several therapeutic strategies are available. Reporting of real-world experience is essential to refining current management recommendations.

Mycobacterial infections in solid organ transplant recipients

Mycobacterium tuberculosis (MTB) infection in solid organ transplant (SOT) recipients remains a major challenge for physicians and surgeons. Active tuberculosis (TB) is associated with increased morbidity and mortality in SOT recipients. MTB usually develops after transplantation in a recipient with latent TB infection (LTBI) before transplantation and may also be transmitted from the donor or acquired from the community. Therefore, screening for LTBI in donors and recipients before transplantation is very important in preventing active disease after transplantation. This review article is based on recently published data, case series, and expert recommendations. We reviewed updated information about the epidemiology, diagnosis, and treatment of latent and active TB before and after transplantation. We also reviewed recent treatments for multidrug-resistant TB.

Latent tuberculosis: Risk factors, screening and treatment in liver transplantation recipients from an endemic area

BACKGROUND

Patients undergoing solid organ transplantation, particularly those who live or have lived in tuberculosis (TB) endemic areas, are at a high risk of developing TB. The majority of post-transplantation TB cases are associated with reactivation of latent TB infection (LTBI). Brazil is in a single position with overlapping areas of high TB endemicity and high transplant activity. In liver transplant (LT), one should be aware of the potential hepatotoxicity associated with the treatment regimens for LTBI.

AIM

To evaluate the frequency of LTBI in LT patients and treatment-related issues.

METHODS

This was a retrospective analysis of a cohort of cirrhotic patients aged ≥ 18 years, who underwent LT at a high-complexity teaching hospital from January 2005 to December 2012.

RESULTS

Overall, 429 patients underwent LT during the study period. Of these, 213 (49.7%) underwent the tuberculin skin test (TST) during the pre-transplant period, and 35 (16.4%) of them had a positive result. The treatment for LTBI was initiated after LT in 12 (34.3%) of the TST-positive patients; in 3 (25.0%), treatment was maintained for at least 6 mo.

CONCLUSION

The prevalence of LTBI was lower than expected. Initiation and completion of LTBI treatment was limited by difficulties in the management of these special patients.

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.

Risk Groups of Developing Active Tuberculosis in Liver Transplant Recipients in a Tuberculosis Endemic Area: Risk Stratification by Chest Image and Interferon Gamma Release Assay

OBJECTIVES

We implemented a stratified risk analysis to predict the development of active tuberculosis (TB) in liver transplantation (LT) recipients based on IGRA and chest images in a TB-endemic area.

METHODS

In this retrospective cohort study, LT recipients who tested for IGRA between May 2008 and December 2017 were included. Chest images compatible with old TB lesions were considered as positive images. LT recipients were divided into six groups: LT recipients with history of treated TB, image (+)/IGRA (+), image (+)/IGRA (-), image (-)/IGRA (+), image (-)/IGRA (-) and LTBI treated. The Cox regression model was used to analyze risk groups.

RESULTS

Among the 717 eligible LT recipients included in this study, 21 patients developed active TB. Incidence rates of TB were 2,261, 724, and 119 cases/100,000 person-years in the 1st, 2nd, and ≥ 3rd year after transplantation, respectively. History of treated TB (HR 18.92; 95% CI 4.10-87.25) and image (+)/IGRA (+) (HR 10.86; 95% CI 2.75-42.89) were independent risk factors for developing active TB. IGRA (+) with a negative image was not a risk factor.

CONCLUSIONS

Our findings suggested that both IGRA and chest images should be considered to identify risk groups for LTBI treatment.

Incidence and Treatment Outcome of Rhinosinusitis before Kidney Transplantation: A Retrospective Cohort Study

BACKGROUND

The use of immunosuppressants after transplantation can aggravate sinus infections. Although kidney transplantation (KT) recipients are administered strong immunosuppressant therapy, there is few consensus or reports on incidence and treatment of rhinosinusitis before KT. This study was undertaken to analyze the results of a cohort of KT recipients that underwent sinonasal evaluation before KT.

METHODS

Observational retrospective cohort data were analyzed from adults who underwent a KT between January 2015 and December 2018. In total, 966 patients were screened by clinical history, nasal endoscopy, and plain X-ray before KT.

RESULTS

A total of 86 patients (8.9%) were diagnosed with rhinosinusitis. Twenty-three of the eighty-six patients (26.7%) who underwent plain X-ray on second follow up were successfully treated with primary and secondary antibiotics, saline irrigation, and INS. From the remaining 63 patients who underwent additional CT on second follow up, 43 patients were treated with primary or secondary antibiotics and 20 patients (10 with chronic rhinosinusitis and 10 with fungal ball) were treated with endoscopic sinus surgery. There were no serious complications affecting patient mortality after KT.

CONCLUSION

We report that 8.9% of patients showed abnormal findings in sinonasal evaluation before KT. Although most patients did not require surgery, surgery is recommended for active rhinosinusitis, which does not respond to medication, and for fungal rhinosinusitis to prevent postoperative sinonasal infection.

Chest Radiographs and CT Findings during Healthcare Workers' Tuberculosis Screening Using Interferon-Gamma Release Assay: Retrospective Observational Study

Purpose

To investigate the incidence of tuberculosis (TB) in healthcare workers (HCWs) with positive interferon-gamma release assay (IGRA) results based on chest X-ray (CXR) and CT findings and determine the role of imaging in the diagnosis of TB.

Materials and Methods

Among 1976 hospital personnel screened for TB using IGRA, IGRA-positive subjects were retrospectively investigated. Clustered nodular and/or linear streaky opacities in the upper lung zone were considered positive on CXR. The CT findings were classified as active, indeterminate, inactive, or normal. The active or indeterminate class was considered CT-positive.

Results

IGRA was positive in 255 subjects (12.9%). CXR and CT were performed in 249 (99.2%) and 113 subjects (45.0%), respectively. CXR- and CT-positive findings were found in 7 of 249 (2.8%) and 9 of 113 (8.0%) patients, respectively. Among the nine CT-positive subjects, active and indeterminate TB findings were found in 6 (5.3%) and 3 (2.7%) patients, respectively. Microbiological tests, including acid-fast bacilli staining, culture, and polymerase chain reaction for TB, were negative in all nine CT-positive subjects. Empirical anti-TB medications were administered to 9 CT-positive subjects, and 3 of these nine subjects were CXR-negative for pulmonary TB.

Conclusion

CT helped diagnose asymptomatic TB in IGRA-positive HCWs.

Evolution of Interferon-Gamma Release Assay Results and Submillisievert Chest CT Findings among Close Contacts of Active Pulmonary Tuberculosis Patients

Background

Latent tuberculosis (TB) infection among TB contacts is diagnosed using plain chest radiography and interferon-gamma release assays (IGRAs). However, plain chest radiographs often miss active TB, and the results of IGRA could fluctuate over time. The purpose of this study was to elucidate changes in the results of the serial IGRAs and in the findings of the serial submillisievert chest computed tomography (CT) scans among the close contacts of active pulmonary TB patients.

Methods

Patients age 20 or older with active pulmonary TB and their close contacts were invited to participate in this study. Two types of IGRA (QuantiFERON-TB Gold In-Tube assay [QFT-GIT] and the T-SPOT.TB test [T-SPOT]) and submillisievert chest CT scanning were performed at baseline and at 3 and 12 months after enrollment.

Results

In total, 19 close contacts participated in this study. One was diagnosed with active pulmonary TB and was excluded from further analysis. At baseline, four of 18 contacts (22.2%) showed positive results for QFT-GIT and T-SPOT; there were no discordant results. During the follow-up, transient and permanent positive or negative conversions and discordant results between the two types of IGRAs were observed in some patients. Among the 17 contacts who underwent submillisievert chest CT scanning, calcified nodules were identified in seven (41.2%), noncalcified nodules in 14 (82.4%), and bronchiectasis in four (23.5%). Some nodules disappeared over time.

Conclusion

The results of the QFT-GIT and T-SPOT assays and the CT images may change during 1 year of observation of close contacts of the active TB patients.

Trends in diagnostic methods and treatment of latent tuberculosis infection in a tertiary care center from 2000 to 2017

Screening for latent tuberculosis infection (LTBI) is indicated before immunosuppressive therapies but is complicated by lack of a gold standard and limited by, e.g., immunosuppression. This study aimed to investigate a series of patients diagnosed with LTBI during screening before immunosuppressive therapy, describing how the use of diagnostic tests and treatment evolved over time. This retrospective cohort study included all individuals diagnosed with LTBI during screening before intended immunosuppressive therapy in a tertiary care hospital between January 2000 and December 2017. Evidence for LTBI, including history, tuberculin skin test (TST), QuantiFERON (QFT) result and suggestive lesions on chest radiography (CXR), and CT scan if available, was analyzed. The study included 295 individuals with LTBI, with median follow-up of 3.8 years (IQR 1.7–7.4 years). During screening, TST, QFT, and CXR were positive in 80.8%, 53.4%, and 22.7%, respectively. Chest CT revealed lesions associated with past tuberculosis infection in around 70%, significantly more frequent than CXR. In patients diagnosed with LTBI, we observed that the use of TST declined over time whereas the use of QFT increased, and that isoniazid was replaced with rifampicin as preferential treatment. Preventive treatment was started in 82.3%, of whom 88.6% completed treatment. During follow-up, no individuals developed active tuberculosis. The diagnosis of LTBI was based on history, TST, QFT, and/or CXR in nearly every possible combination, but mostly on TST and QFT. The most striking trends were the decreased use of TST, increased use of QFT, and the replacement of isoniazid with rifampicin for treatment.

Risk factors of tuberculosis after liver transplant in a tertiary care hospital

BACKGROUND

Tuberculosis (TB) is a serious opportunistic infection in liver transplant (LT) recipients with a high rate of morbidity and mortality. This study aims to clarify the frequency and risk factors for tuberculosis in LT recipients.

METHODS

A total of 884 LT recipients were investigated retrospectively at China Medical University Hospital, Taichung, Taiwan. We performed a case-control study (1:2) to investigate the potential risk factors and disease onset of TB after LT.

RESULTS

Among the 884 LT recipients, 25 of TB cases (2.8%) were reported from 2009 to 2016. The overall incidence of TB was 744 cases per 100,000 patient-year, which was 18-fold higher than the general population in Taiwan. The median time to develop TB after liver transplant was 20 months. Of the TB cases, 15 were pulmonary TB and 10 were extra-pulmonary TB. Five cases of those extra-pulmonary TB occurred in the first post-transplant year. Overall five-year survival rate was 63.3%. Multivariate analyses identified apical fibrotic change in pre-transplant computed tomographic (CT) finding and the exposure to mammalian target of rapamycin (mTOR) inhibitors before TB event as independent risk factors for TB development (Odd ratio (OR) 10.79, 95% confidence interval (CI), 1.73-67.49, p = 0.01; OR 3.847, 95% CI 0.80-18.51, P = 0.09, respectively).

CONCLUSION

TB incidence in LT recipients is high in this study. Among those post-transplant recipients with long-term immunosuppression, abnormal CT finding and exposure to mTOR inhibitors before liver transplant might be the risk factors for TB.

Indian guidelines on imaging of the small intestine in Crohn's disease: A joint Indian Society of Gastroenterology and Indian Radiology and Imaging Association consensus statement

The Indian Society of Gastroenterology (ISG) Task Force on Inflammatory Bowel Disease and the Indian Radiological and Imaging Association (IRIA) developed combined ISG-IRIA evidence-based best-practice guidelines for imaging of the small intestine in patients suspected to have or having Crohn's disease. The 29 consensus statements, developed through a modified Delphi process, are intended to serve as reference for teaching, clinical practice, and research.

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.

Mycobacterium tuberculosis infections in solid organ transplantation: Guidelines from the infectious diseases community of practice of the American Society of Transplantation

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of tuberculosis in the pre- and post-transplant period. The challenges of screening for both latent and active TB in the setting of transplantation are reviewed. The use of interferon gamma release assays for detection of latent tuberculosis is discussed and compared to tuberculin skin testing. Given the limitations of both testing modality, it is important to consider exposure history and chest imaging. The clinical manifestations of active tuberculosis in transplantation are covered. New recommendations for treatment of latent tuberculosis and active tuberculosis are included.

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.

Chest X-ray and chest CT findings in patients diagnosed with pulmonary tuberculosis following solid organ transplantation: a systematic review

The objective of this systematic review was to select articles including chest X-ray or chest CT findings in patients who developed pulmonary tuberculosis following solid organ transplantation (lung, kidney, or liver). The following search terms were used: "tuberculosis"; "transplants"; "transplantation"; "mycobacterium"; and "lung". The databases used in this review were PubMed and the Brazilian Biblioteca Virtual em Saúde (Virtual Health Library). We selected articles in English, Portuguese, or Spanish, regardless of the year of publication, that met the selection criteria in their title, abstract, or body of text. Articles with no data on chest CT or chest X-ray findings were excluded, as were those not related to solid organ transplantation or pulmonary tuberculosis. We selected 29 articles involving a collective total of 219 patients. The largest samples were in studies conducted in Brazil and South Korea (78 and 35 patients, respectively). The imaging findings were subdivided into five common patterns. The imaging findings varied depending on the transplanted organ in these patients. In liver and lung transplant recipients, the most common pattern was the classic one for pulmonary tuberculosis (cavitation and "tree-in-bud" nodules), which is similar to the findings for pulmonary tuberculosis in the general population. The proportion of cases showing a miliary pattern and lymph node enlargement, which is most similar to the pattern seen in patients coinfected with tuberculosis and HIV, was highest among the kidney transplant recipients. Further studies evaluating clinical data, such as immunosuppression regimens, are needed in order to improve understanding of the distribution of these imaging patterns in this population.

Prevention and Management of Tuberculosis in Solid Organ Transplant Recipients. Infect Dis Clin North Am. 2018;32:703-718. [PMID: 30146031 DOI: 10.1016/j.idc.2018.05.002]

Solid organ transplant recipients are at an increased risk of tuberculosis and transplant candidates should be screened early in their evaluation with a detailed history, tuberculin skin test or tuberculosis interferon-gamma release assay, and chest radiograph. For latent tuberculosis treatment, isoniazid and rifamycin-based regimens have advantages and disadvantages; treatment decisions should be customized. Tuberculosis after solid organ transplantation generally occurs after months or years; early infections should raise the possibility of donor-derived infections. Tuberculosis diagnosis and treatment in solid organ transplant recipients may be complicated by protean manifestations, drug interactions, and adverse drug reactions.

A practical approach to tuberculosis diagnosis and treatment in liver transplant recipients in a low-prevalence area

Solid organ transplant candidates/recipients are at risk of mycobacterial infections. Although guidelines on the management of latent tuberculosis infection and active tuberculosis are available for solid organ transplant recipients, limited guidance focuses on end-stage liver disease or liver transplant recipients who require management in a referral center. Therapeutic challenges arise from direct antituberculosis drug-related hepatotoxicity, and substantial metabolic interactions between immunosuppressive and antituberculosis drugs. Another issue is the optimal timing of therapy with regards to the time of transplantation. This review focuses on the importance of tuberculosis screening with immunological tests, challenges in the diagnosis, management, and treatment of latent tuberculosis infection and active tuberculosis, as well as risk assessment for active tuberculosis in the critical peri-liver transplantation period. We detail therapeutic adjustments required for the management of antituberculosis drugs in latent tuberculosis infection and active tuberculosis, particularly when concomitantly using rifampicin and immunosuppressive drugs.

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.

Tuberculosis after liver transplantation in a large center in New York City: QuantiFERON® -TB Gold-based pre-transplant screening performance and active tuberculosis post-transplant

INTRODUCTION

Pre-transplant screening for latent tuberculosis infection (LTBI) is a complex consideration that varies by institution. Inconsistent performance of interferon-gamma release assay (IGRA) further complicates screening. Data regarding LTBI screening outcomes and test characteristics in a large, foreign-born pre-transplant population within the United States are limited.

METHODS

In this retrospective study, patients who received QuantiFERON^® -TB Gold (QFT) prior to liver transplantation (LT) were included. Characteristics of patients were compared by QFT result, and predictors of indeterminate results were evaluated. Similar comparisons were performed between patients who developed active TB and those who did not.

RESULTS

Of 148 patients screened, the rate of positive, indeterminate, and negative testing was 13.5% (20/148), 27% (40/148), and 59% (88/148), respectively. An indeterminate QFT result was more than 16 times more likely in patients with a Model for End-stage Liver Disease score >25 (odds ratio [OR] 16.7; 95% confidence interval [CI], 2.1-132.0; P = .008) and more than 4 times when performed in our institution's lab compared with commercial lab (OR 4.1; 95% CI, 1.34-12.44; P = .013). The overall TB incidence was 1102/100 000 transplant cases. No patient who developed active TB had a positive QFT. All were born outside of the United States (P = .06) and had pre-transplantation chest imaging demonstrating granulomatous disease (P = .006).

CONCLUSION

Our experience further highlights the challenges of LTBI screening prior to LT and suggests that QFT may be a poor predictor of active TB in higher risk pre-transplant populations. Candidates should be screened as early as possible to optimize QFT performance, and local epidemiological data should be used to create institution-specific screening protocols in areas with large populations from TB-endemic regions. Management should consider TB risk factors, QFT, and imaging instead of reliance on QFT testing alone.

Imaging of the small intestine in Crohn's disease: Joint position statement of the Indian Society of Gastroenterology and Indian Radiological and Imaging Association

The Indian Society of Gastroenterology (ISG) Task Force on Inflammatory Bowel Disease and the Indian Radiological and Imaging Association (IRIA) developed combined ISG-IRIA evidence-based best-practice guidelines for imaging of the small intestine in patients with suspected or known Crohn's disease. These 29 position statements, developed through a modified Delphi process, are intended to serve as reference for teaching, clinical practice, and research.

Risk of tuberculosis after lung transplantation: the value of pretransplant chest computed tomography and the impact of mTOR inhibitors and azathioprine use

BACKGROUND

It is necessary to determine the incidence and risk factors for tuberculosis (TB), as well as strategies to assess and treat latent tuberculosis infection (LTBI) in lung transplant recipients.

METHODS

A retrospective cohort study of 398 lung transplant recipients was performed. Episodes of TB were studied and the incidence rate was calculated. Logistic regression analysis was used to analyze specific variables as potential risk factors for TB.

RESULTS

Median follow-up was 558 days (range 1-6636). Six cases (1.5%) of TB were documented in 398 transplant patients. The incidence density of TB was 406.3 cases/10(5) patient-years (95% confidence interval [CI] 164.7-845), which is higher than in the general population (13.10 cases/10(5) person-years). All cases occurred in the period 1993-2006, when the tuberculin skin test (TST) and treatment of LTBI in positive TST patients were not part of the protocol. Pretransplant computed tomography (CT) showed residual lesions in 50% of patients who developed TB, although the TST was negative and the chest radiograph was inconclusive. Multivariate analysis identified the presence of residual lesions in the pretransplant chest CT (odds ratio [OR] 11.5, 95% CI 1.9-69.1, P = 0.008), use of azathioprine (OR 10.6, 95% CI 1.1-99.1, P = 0.038), and use of everolimus (OR 6.7, 95% CI 1.1-39.8, P = 0.036) as independent risk factors for TB.

CONCLUSIONS

Residual lesions in the pretransplant chest CTs and the use of azathioprine and mTOR inhibitors are associated with the risk of TB.

Exposure to ionizing radiation during liver transplantation evaluation, waitlist time, and in the postoperative period: a cause for concern

Substantial evidence has linked ionizing radiation exposure (RE) to oncogenesis. Patients evaluated for transplantation undergo extensive diagnostic imaging and have increased baseline cancer risk factors. The objective was to examine exposure in a cohort of patients undergoing evaluation and liver transplantation. Radiation exposure from all diagnostic examinations and procedures were retrospectively recorded. Radiation exposure is reported in mSv, a standardized measure of the detrimental biologic effect of radiation which allows for population-level comparisons. Seventy-four patients (69% male, mean 57 years) were evaluated, of which 13 of 35 subsequently listed patients were transplanted; an additional 18 previously evaluated patients were also transplanted during 2010. The most common indications were hepatitis C (55%) and hepatocellular carcinoma (HCC) (30%). The median observation period was 14 months. In all, 1,826 imaging examinations were performed, of which 408 (22%) involved considerable ionizing radiation and were the focus of investigation. Median annualized effective RE was 51 mSv (interquartile range [IQR]: 19,126), with 10% exposed to almost twice the amount of radiation recommended for a 5-year period. Patients with HCC received significantly (P < 0.00001) higher median annualized effective RE than patients without HCC, 137 mSv (IQR: 87,259) versus 32 mSv (IQR: 13,57), respectively. Computed tomography (CT) abdomen (23%) and chest (16%) accounted for the most common exposures, with CT abdomen accounting for 46% of overall cohort RE.

CONCLUSION

Patients undergoing evaluation and liver transplantation at our center are exposed to very high levels of ionizing radiation. Although long-term effects in these patients are yet to be defined, the theoretical increased risk of malignancy must be given its due consideration. Routine use of nonradiation imaging and reconsideration of indications may be preferred and justified in this population.

Results of implementation of preventive recommendations for tuberculosis after renal transplantation in an endemic area

This retrospective cohort study assessed the results of the implementation of preventive recommendations for tuberculosis (TB) among renal transplant recipients in an endemic area (Rio de Janeiro, Brazil). Subjects were defined as at high risk for TB if they had latent tuberculosis infection (LTBI), reported recent close contact with individuals with TB or received a graft from a donor with LTBI. A 6-month course of isoniazid preventive therapy (IPT) was targeted to high-risk subjects. The study end point was TB confirmed by culture. Altogether, 535 patients were included. Median follow-up was 59 months. The overall cumulative incidence of TB was 2.1% while among the 274 patients in whom the preventive protocol was fully implemented, the incidence was only 0.7%. The incidence of TB among 75 high-risk recipients not treated with isoniazid (7%) was significantly higher than that observed in 209 untreated low-risk patients (1%, p = 0.006) and in 65 high-risk subjects that received IPT (no case, p = 0.03). In conclusion, the implementation of preventive recommendations for TB in an endemic area allowed the appropriate discrimination between high- and low-risk renal transplant recipients and was associated with long-term reduction in the incidence of this complication among high-risk subjects.

Challenging issues in tuberculosis in solid organ transplantation

Solid organ transplant (SOT) recipients are at risk for opportunistic infections including tuberculosis. Although guidelines on the management of latent tuberculosis and active tuberculosis are available, there remain a number of clinical areas with limited guidance. We discuss challenges in the diagnosis, management, and treatment of latent and active tuberculosis in SOT candidates and recipients who reside in low-tuberculosis-prevalence areas. We discuss the diagnosis of latent tuberculosis in SOT candidates/recipients using tuberculin skin tests and interferon-γ release assays and risk stratification of SOT candidates/recipients that would identify individuals at high risk for latent tuberculosis despite negative test results. Through a careful review of posttransplant tuberculosis cases, we identify a history of treated tuberculosis in SOT recipients as a risk factor for development of posttransplant active tuberculosis. Finally, we include comparisons of recommendations by several large transplant organizations and identify areas for future research.

Hepatocyte nuclear factor 1β is a novel prognostic marker independent of the Milan criteria in transplantable hepatocellular carcinoma: a retrospective analysis based on tissue microarrays

We retrospectively investigated the prognostic value of hepatocyte nuclear factor 1 (HNF1) proteins in 159 liver transplant patients with hepatocellular carcinoma (HCC), including 36 (22.6%) exceeding the Milan criteria. The expression of alpha-fetoprotein (AFP), HNF1α, and HNF1β was examined with immunohistochemistry on duplicate tissue microarray slides containing HCC tumor explants. The times to recurrence and cancer death were analyzed with a Cox regression model and were compared according to the expression of markers of interest. We compared risk predictions with area under the receiver operator curves (AUROCs) and C statistics. AFP, HNF1α, and HNF1β were positive in 22.6%, 46.5%, and 61.0% of the tumor immunoprofiles, respectively. Although several variables were associated with the times to recurrence and cancer death in univariate Cox analyses, only AFP expression for the time to recurrence and the Milan criteria and HNF1β expression for the times to recurrence and cancer death remained significant after multivariate adjustments. The expression of HNF1β (but not HNF1α) was related to a serum AFP level ≥ 200 ng/mL, microvascular invasion, and AFP expression (P < 0.05 for all). A subgroup analysis showed that in the group meeting the Milan criteria, recurrence and cancer death rates at 10 years in the HNF1β-negative patients were approximately one-tenth of those in the HNF1β-positive patients, but the difference was not significant in the group exceeding the Milan criteria. The addition of HNF1β expression to the Milan criteria increased the C statistics and AUROCs for both recurrence and mortality (P < 0.05 for all). In conclusion, the immunohistological detection of HNF1β predicts recurrence and HCC-specific death after transplantation and provides an additive benefit in comparison with the Milan selection criteria on their own.