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

Diagnostic Accuracy of High-Resolution Computed Tomography (HRCT) in Detecting Pneumocystis carinii in Renal Transplant Patients With Pulmonary Infection: A Study Using Bronchoalveolar Lavage As the Gold Standard

INTRODUCTION

Patients receiving renal transplants have weakened immune systems and are more vulnerable to lung infections.

OBJECTIVES

To determine the diagnostic accuracy of high-resolution computed tomography (HRCT) in detecting pneumocystis carinii in renal transplant patients presenting with pulmonary infection in a tertiary care transplant center, keeping bronchoalveolar lavage (BAL) as the gold standard.

METHODS

 This cross-sectional study was conducted at the Department of Radiology, Sindh Institute of Urology and Transplant, Karachi, from February 14, 2023, to August 13, 2023. Using a non-probability consecutive sampling technique, we enrolled 81 post-renal transplant patients, aged 20 to 60 years, of both genders, who were receiving immunosuppressive therapy and referred to the Radiology Department for HRCT as part of a workup for pulmonary infection. Patients presented with pulmonary infection underwent HRCT and BAL. Diagnostic accuracy was determined and data was analyzed.

RESULTS

In this study, 81 patients were enrolled with a mean age of 35.4±11.3 years. There were 56 (69.1%) male and 25 (30.9%) female patients. The mean duration of renal transplant was 18.09±12.8 months. The mean duration of symptoms was 5.32±2 days. Diabetes was present in 43 (53.1%) patients. The sensitivity of HRCT in diagnosing pneumocystis carinii was 93%, specificity was 91.7%, positive predictive value was 96.4%, negative predictive value was 84.6%, and diagnostic accuracy was 92.5%, taking BAL as the gold standard.

CONCLUSION

HRCT is a good imaging modality to diagnose pneumocystis carinii in renal transplant patients.

Diagnosis of pulmonary tuberculosis with 3D neural network based on multi-scale attention mechanism

This paper presents a novel multi-scale attention residual network (MAResNet) for diagnosing patients with pulmonary tuberculosis (PTB) by computed tomography (CT) images. First, a three-dimensional (3D) network structure is applied in MAResNet based on the continuity and correlation of nodal features on different slices of CT images. Secondly, MAResNet incorporates the residual module and Convolutional Block Attention Module (CBAM) to reuse the shallow features of CT images and focus on key features to enhance the feature distinguishability of images. In addition, multi-scale inputs can increase the global receptive field of the network, extract the location information of PTB, and capture the local details of nodules. The expression ability of both high-level and low-level semantic information in the network can also be enhanced. The proposed MAResNet shows excellent results, with overall 94% accuracy in PTB classification. MAResNet based on 3D CT images can assist doctors make more accurate diagnosis of PTB and alleviate the burden of manual screening. In the experiment, a called Grad-CAM was employed to enhance the class activation mapping (CAM) technique for analyzing the model's output, which can identify lesions in important parts of the lungs and make transparent decisions.

Factors associated with pulmonary infection in kidney and kidney-pancreas transplant recipients: a case-control study

OBJECTIVE

To evaluate the etiology of and factors associated with pulmonary infection in kidney and kidney-pancreas transplant recipients.

METHODS

This was a single-center case-control study conducted between December of 2017 and March of 2020 at a referral center for kidney transplantation in the city of Belo Horizonte, Brazil. The case:control ratio was 1:1.8. Cases included kidney or kidney-pancreas transplant recipients hospitalized with pulmonary infection. Controls included kidney or kidney-pancreas transplant recipients without pulmonary infection and matched to cases for sex, age group, and donor type (living or deceased).

RESULTS

A total of 197 patients were included in the study. Of those, 70 were cases and 127 were controls. The mean age was 55 years (for cases) and 53 years (for controls), with a predominance of males. Corticosteroid use, bronchiectasis, and being overweight were associated with pulmonary infection risk in the multivariate logistic regression model. The most common etiologic agent of infection was cytomegalovirus (in 14.3% of the cases), followed by Mycobacterium tuberculosis (in 10%), Histoplasma capsulatum (in 7.1%), and Pseudomonas aeruginosa (in 7.1%).

CONCLUSIONS

Corticosteroid use, bronchiectasis, and being overweight appear to be risk factors for pulmonary infection in kidney/kidney-pancreas transplant recipients, endemic mycoses being prevalent in this population. Appropriate planning and follow-up play an important role in identifying kidney and kidney-pancreas transplant recipients at risk of pulmonary infection.

Miliary tuberculosis in an immune-competent Bangladeshi man-A case report

Miliary tuberculosis is a disseminated and active form of tuberculosis caused by Mycobacterium tuberculosis. It frequently affects immunocompromised patients. However, immune-competent hosts are reported rarely. Herein, we reported a case of miliary tuberculosis of a 40-year-old immune-competent Bangladeshi man presented with pyrexia of unknown origin.

Clinical manifestations and immune response to tuberculosis

Tuberculosis is a far-reaching, high-impact disease. It is among the top ten causes of death worldwide caused by a single infectious agent; 1.6 million tuberculosis-related deaths were reported in 2021 and it has been estimated that a third of the world's population are carriers of the tuberculosis bacillus but do not develop active disease. Several authors have attributed this to hosts' differential immune response in which cellular and humoral components are involved, along with cytokines and chemokines. Ascertaining the relationship between TB development's clinical manifestations and an immune response should increase understanding of tuberculosis pathophysiological and immunological mechanisms and correlating such material with protection against Mycobacterium tuberculosis. Tuberculosis continues to be a major public health problem globally. Mortality rates have not decreased significantly; rather, they are increasing. This review has thus been aimed at deepening knowledge regarding tuberculosis by examining published material related to an immune response against Mycobacterium tuberculosis, mycobacterial evasion mechanisms regarding such response and the relationship between pulmonary and extrapulmonary clinical manifestations induced by this bacterium which are related to inflammation associated with tuberculosis dissemination through different routes.

Differences in CT imaging signs between patients with tuberculosis and those with tuberculosis and concurrent lung cancer

OBJECTIVE

The purpose of this study was to compare the differences in imaging features between patients with pulmonary tuberculosis (TB) alone and patients with TB complicated with lung cancer (LCA) as well as to investigate the diagnostic value of CT in these two groups.

METHODS

In this retrospective study, 110 patients with confirmed TB admitted to the Second Affiliated Hospital of Hainan Medical University from March 2020 to April 2021 were collected and divided into TB+LCA group (50 cases, diagnosed with TB complicated with lung cancer) and TB group (60 cases, diagnosed with TB alone) according to actual diagnosis. The CT results of both groups were analyzed by the same group of physicians in a double-blind manner. The diagnostic value of CT for TB alone and TB complicated with lung cancer was calculated. The differences in CT imaging characteristics between the two groups were investigated. The differences in the structural characteristics of para-cancerous tissue between the two groups were analyzed.

RESULTS

The diagnostic accuracy of CT was 91.67% in TB patients (55/60) and 92.00% in TB+LCA patients (46/50) without significant difference (X² =0.004, P=0.949). The detection rate of spiculation, lobulation and cavitation in TB+LCA group was significantly higher than that in TB group (P<0.05), and the distribution, size and wall thickness of cavitation varied significantly between the two groups (P<0.05). Patients in TB group had higher percentage of mediastinal lymph node calcification, peripheral satellite lesion, and mediastinal lymph node enlargement around the TB lesions compared with those in TB+LCA group (P<0.05).

CONCLUSION

CT has certain application value in differentiating TB alone from TB complicated with lung cancer, and there are many similarities in the imaging features of the two conditions. CT can be considered as a preliminary means of differential diagnosis of TB complicated with lung cancer, which is helpful to the primary screening diagnosis of lung cancer.

Automated screening of COVID-19 using two-dimensional variational mode decomposition and locally linear embedding

In order to aid imaging physicians to effectively screen chest radiography medical images for presence of Coronavirus Disease 2019 (COVID-19), a novel computer aided diagnosis technology for automatic processing of COVID-19 images is proposed based on two-dimensional variational mode decomposition (2D-VMD) and locally linear embedding (LLE). 2D-VMD algorithm is used to decompose normal and COVID-19 images, and then feature extraction of intrinsic mode functions (IMFs) using Gabor filter. To better extract low-dimensional parameters which are useful for COVID-19 diagnosis, the performance of two dimensionality reduction techniques of principal component analysis (PCA) and LLE are compared, and the LLE is shown to offer satisfactory effect of dimension reduction. Thereafter, the particle swarm optimization-support vector machine (PSO-SVM) algorithm is used to classify. The simulation results show that the proposed technology has achieved accuracy of 99.33%, precision of 100%, recall of 98.63% and F-Measure of 99.31%. Hence, the developed diagnosis technology can be used as an important auxiliary tool to assist diagnosis of imaging physicians.

Clinical characteristics of tuberculous infection following renal transplantation

OBJECTIVE

This study investigated the clinical characteristics of patients with tuberculosis (TB) following renal transplantation (RT) in order to identify markers or signs that can facilitate early diagnosis.

METHODS

A retrospective analysis was performed on 12 cases of Mycobacterium tuberculosis infection treated at our hospital between 2005 and 2020.

RESULTS

The incidence of TB after RT at our hospital was 0.9%, and the median postoperative onset time was 22 months. The average age of patients included in our analysis was 44.2 ± 9.4 years; 11 of the 12 patients were male, and most patients had (low) fever as the first or only manifestation. Five patients had respiratory symptoms; 5 had typical computed tomography (CT) presentation; and 2 had a confirmed history of TB. Two sputum smears from 12 patients were positive by acid fast staining, and M. tuberculosis was detected in peripheral blood samples by metagenomic next-generation sequencing (NGS). One patient had a positive result in the purified protein derivative (PPD) test, 7 were positive with the interferon gamma release assay (IGRA), 8/12 patients were confirmed to have TB infection by NGS and 1 was confirmed positive by lung biopsy.

CONCLUSION

Because of the use of immunosuppressive agents, most patients with TB following RT have atypical clinical symptoms and CT findings, and may have a high probability of a false negative result with the traditional PPD test and a low probability of M. tuberculosis detection, making early diagnosis difficult. Therefore, in RT recipients with prolonged fever of unknown origin and unusual clinical manifestations, especially those who are unresponsive to antibiotic treatment, a diagnosis of TB should be considered. The interferon gamma release assay and NGS are relatively new detection methods with high sensitivity and specificity; these along with regular, repeated testing by various approaches can aid the early diagnosis of TB.

Mycobacterium tuberculosis in solid organ transplant donors and recipients

PURPOSE OF REVIEW

Due to impaired immune response, solid organ transplant (SOT) recipients are susceptible to tuberculosis (TB) and its subsequent morbidity and mortality. Current prevention strategies, diagnostic and treatment approach to TB infection in donors and recipients were reviewed in this article.

RECENT FINDINGS

Screening of latent tuberculosis infection (LTBI) in donors and recipients is the cornerstone of TB-preventive strategy in recipients and requires an assessment of TB risk factors, TB-specific immunity testing, and radiographic evaluation. Interferon-gamma release assay has superseded the tuberculin skin test in LTBI evaluation despite its recognized limitations. LTBI treatment should be offered to transplant candidates and living donors before transplantation and donation, respectively. Diagnosis of TB disease can be challenging because of nonspecific clinical presentation in the recipient and is limited by the sensitivity of current diagnostics. The approach to LTBI and TB disease treatment is similar to the general population, but can be challenging because of potential drug interactions and toxicities.

SUMMARY

The appropriate evaluation of donors and recipients for TB can mitigate posttransplant TB disease. Current approaches to diagnosis and treatment parallels that of immunocompetent hosts. Future research evaluating existing and novel diagnostics and treatment in transplant recipients is needed.

Empiric vs screening-based use of isoniazid for tuberculosis prophylaxis: Safety and effectiveness in lung transplant recipients in Saudi Arabia

Background

Tuberculosis (TB) is a major complication following transplantation. The likelihood of TB may be increased in transplant patients living in TB‐endemic areas such as Saudi Arabia. In areas where TB is less common, guidelines recommend isoniazid (INH) for TB prophylaxis depending on patient and donor screening results. However, in TB‐endemic regions, studies have supported its use in all transplant patients regardless of TB screening results. This study aimed to compare the safety and effectiveness of administering INH prophylaxis therapy based on the TB screening results of lung transplant (LT) recipients.

Methods

We conducted a single‐center retrospective cohort study on LT recipients. The outcomes were compared between patients who were administered screening‐based prophylaxis (SBP) with INH based on their tuberculin skin tests (TSTs) or QuantiFERON results and those who were administered empirical prophylaxis (EP) with INH regardless of TB screening results. The primary endpoint was the incidence of TB infection, and the secondary endpoints were INH‐induced hepatotoxicity and INH resistance.

Results

A total of 50 patients received SBP and 30 received EP. TB incidences were 8% and 0%, respectively (P = .0487). One of these patients had INH resistance, and one patient experienced INH‐induced hepatotoxicity (P = .1591); both were in the SBP group.

Conclusion

The low rates of TB infection, INH‐induced hepatotoxicity, and INH resistance in the EP group suggest that INH prophylaxis appears to prevent TB and can be safely used in all LT recipients. However, prospective studies using large sample sizes are required to confirm these findings.

Diagnostic Value of Flow Cytometry in Kidney Transplant Recipients With Active Pulmonary Tuberculosis

OBJECTIVES

Long-term use of immunosuppressant drugs in kidney transplant recipients leads to immunosuppression. When active pulmonary tuberculosis infection occurs, lymphocyte proliferation and function are impaired, and the clinical symptoms of patients are not typical, which often leads to delay in diagnosis.

MATERIALS AND METHODS

We collected and analyzed the peripheral blood lymphocytes of hospitalized patients with active pulmonary tuberculosis and other types of pulmonary infection after kidney transplant within 2 years. The proportion and absolute values of lymphocytes were obtained by a flow cytometer.

RESULTS

There were significant differences in the proportion of CD8+ subsets between active pulmonary tuberculosis and bacterial pneumonia in kidney transplant recipients. If the proportion of CD8+ subsets in peripheral blood is over 33.27%, then the active pulmonary tuberculosis diagnosis sensitivity is higher than 88.9% and specificity is higher than 83.3%.

CONCLUSIONS

Analysis of peripheral lymphocyte subsets is helpful in the early diagnosis of kidney transplant recipients with active pulmonary tuberculosis. It should be added into routine examinations of kidney transplant recipients who have an ambiguous diagnosis between active pulmonary tuberculosis and bacterial pneumonia.

Miliary pattern, a classic pulmonary finding of tuberculosis disease

Introduction

The increase in age of the population and in the use of immunosuppressive treatment makes tuberculosis (TB) with hematogenous or lymphatic dissemination a current problem.

Methods

We collected all the patients diagnosed with tuberculosis with miliary pulmonary pattern at the Santiago de Compostela University Teaching Hospital (NW Spain) from 1 January 2006 to 31 December 2015.

Results

A total of 27 patients were included, 70.4% women, with a median age of 69.0 years old. A cause of immunosuppression was observed only in 51.9% of patients. The majority of the cases (65.0%) presented pulmonary affectation. The most frequently isolated species was Mycobacterium tuberculosis (88.9%). Multiresistance to first-line antituberculosis drugs was observed only in 3.7%. 92.6% of the patients received treatment with Isoniazid, Rifampicin and Pyrazinamine, associated in 48.1% of them with Ethambutol. Two patients died during admission and there were no recurrences in the 2-years follow-up.

Conclusions

Miliary tuberculosis remains a current pathology. Most patients do not have a known cause of immunosuppression. The response to the typical treatment is usually good.

Miliary Tuberculosis Presenting with Hyponatremia and ARDS in an 82-Year-Old Immunocompetent Female

An immunocompetent 82-year-old female was admitted to our hospital due to fever without clear origin and hyponatremia. In the following days, an acute and bilateral pulmonary infiltrate appeared with a progressive worsening in respiratory function. Chest x-ray and CT (Computed tomography) showed bilateral reticulonodular infiltrates. Bronchoscopic aspiration and bronchoalveolar lavage (BAL), and transbronchial lung biopsy (TBBX) studies did not reveal microbiological and histopathological diagnosis. Broad-spectrum antibiotics were non-effective, and the patient died due to respiratory failure. Necropsy study revealed a miliary tuberculosis affecting lungs, liver, bone marrow, spleen, kidney, arteries, pancreas, and adrenal glands. Some weeks after the patient´s death, mycobacterial cultures from sputum, BAL and TBBX samples were positive for Mycobacterium tuberculosis.