Evaluation of Immunohistochemistry Technique for Diagnosis of Extrapulmonary Tuberculosis in Biopsy Tissue Specimen as Compared to Composite Diagnostic Criteria

A retrospective study of extrapulmonary tuberculosis in the Khuzestan province of southwest Iran between 2002 and 2023

BACKGROUND

Worldwide, tuberculosis (TB) is among the most common causes of death. To our knowledge, there has been no study showing the prevalence of EPTB in Khuzestan province. Therefore, the objective of this research was to investigate the prevalence of EPTB in patients with or without pulmonary TB in different cities of Khuzestan province from 2002 to 2023. Additionally, the correlation between patient's gender, and age groups with the disease was also investigated.

METHODS

In this retrospective study, the existing records in Tuberculosis Regional Reference Laboratory of Khuzestan province related to patients were used. The research was carried out by investigating the archive information in 19 years (from 1st January 2002 to December 30, 2023). All confirmed cases of EPTB and simultaneous EPTB and PTB, based on laboratory results and medical examination were included in the study. Patients with incomplete information and military TB were excluded from the study. Information collected from patients includes age, gender, involved organ, place of residence, and year of disease.

RESULTS

A total of 12,900 EPTB-related medical records were extracted from Tuberculosis Regional Reference Laboratories in southwest Iran, Ahvaz. After excluding records, 12,836 clinically diagnosed or laboratory-confirmed tuberculosis patients were included in this study, including 5991 patients with simultaneous PTB and EPTB, and 6845 patients with EPTB only. The mean age of male EPTB patients was 37.5 years (SD ± 14.6), while the mean age of male patients with simultaneous PTB and EPTB was 45.8 years (SD ± 15.3). The mean age of female patients with EPTB only, and with simultaneous PTB and EPTB was 31.2 years (SD ± 12.6), and 31.5 years respectively.

DISCUSSION

tuberculosis is a systemic disease with different clinical manifestations. This study described different epidemiologic patterns of concurrent EPTB. The proportion of different types of EPTB was simultaneously determined for a group of hospitalized patients and shown to be different with gender and age. This study will likely increase clinicians' awareness of the disease and help them better address diagnostic challenges and improve treatment outcomes for patients with EPTB.

Imaging of musculoskeletal tuberculosis

Tuberculosis (TB) represents a major public health problem worldwide. Any tissue may be infected. Involvement of the musculoskeletal (MSK) system account for 1-3% of all tuberculous infections. MSK TB may manifest as tuberculous spondylitis, arthritis, osteomyelitis, and soft tissue infections. Although TB spondylitis may present with distinctive imaging features compared to pyogenic infections of the spine, the imaging semiology of extra-spinal TB infections is mostly nonspecific and may mimic other lesions. TB infections should therefore always be considered in the differential diagnosis, particularly in immunocompromised patients. The aim of this article is to review the imaging features of spinal and extra-spinal MSK TB. Magnetic resonance imaging is considered the modality of choice to make the diagnosis and to evaluate the extent of the disease.

Decoding the hidden realm: Molecular pioneering unravelling osteoarticular tuberculosis diagnosis

Osteoarticular tuberculosis (TB), a form of extrapulmonary tuberculosis, refers to the involvement of Mycobacterium tuberculosis (M.tb) in the bones and joints. While pulmonary tuberculosis is the most common form, osteoarticular TB represents a relatively rare but significant manifestation, accounting for approximately 1-3% of all TB cases. Accurate and timely diagnosis plays a pivotal role in the management of osteoarticular TB. Conventional diagnostic methods for osteoarticular TB, such as acid-fast bacilli smear microscopy and culture, have limitations in terms of sensitivity, specificity, and turnaround time. The purpose of this review is to comprehensively evaluate and synthesize the existing literature on molecular pioneering in osteoarticular TB diagnosis. Molecular techniques, such as nucleic acid amplification tests and gene-based assays, have emerged as promising tools for diagnosing TB. These techniques target specific genetic sequences of M.tb, enabling rapid and sensitive detection of the pathogen. However, the diagnostic accuracy, advantages, and limitations of these molecular techniques in the context of osteoarticular TB diagnosis require further investigation and consolidation of evidence. Furthermore, this review aims to identify areas for future research and development in the field of molecular diagnostics for osteoarticular TB.

Targeted nanopore sequencing using clinical specimens for the rapid diagnosis of extrapulmonary tuberculosis

BACKGROUND

The clinical presentation of extrapulmonary tuberculosis (EPTB) is atypical and it is easily confused with other diseases such as common infections, making prompt diagnosis a great challenge. This study aimed to evaluate the accuracy of targeted nanopore sequencing (TNS) in the diagnosis of EPTB. The diagnostic accuracy of TNS using different types of extrapulmonary specimens was also evaluated.

METHODS

We reviewed the clinical data of patients with suspected EPTB for whom TNS was conducted and who were hospitalized at our center. The true positive, false positive, false negative, and true negative values were determined. Indices of diagnostic accuracy were computed, including sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the curve (AUC) for TNS and acid-fast bacilli (AFB) culture, and compared with those from clinical diagnosis.

RESULTS

149 patients were included in the analysis. The overall sensitivity, specificity, PPV, NPV, and AUC of TNS for the diagnosis of EPTB were 86.4%, 87.5%, 97.3%, 55.3%, and 0.87, respectively. For diagnosis by AFB culture, these values were 25.6%, 100.0%, 100.0%, 20.5%, and 0.63, respectively. The most common specimens used were lymph node tissue, cerebrospinal fluid, pleural effusion, and pleural tissue. The diagnostic accuracy of TNS using all types of extrapulmonary specimens was good.

CONCLUSIONS

TNS demonstrates good diagnostic accuracy in the rapid diagnosis of EPTB and this was true across different types of extrapulmonary specimens.

Diagnosis of extra pulmonary tuberculosis: An update on novel diagnostic approaches

Tuberculosis (TB) remains a major global public health problem worldwide. Though Pulmonary TB (PTB) is mostly discussed, one in five cases of TB present are extrapulmonary TB (EPTB) that manifests conspicuous diagnostic and management challenges with respect to the site of infection. The diagnosis of EPTB is often delayed or even missed due to insidious clinical presentation, pauci-bacillary nature of the disease, and lack of laboratory facilities in the resource limited settings. Culture, the classical gold standard for the diagnosis of tuberculosis, suffers from increased technical and logistical constraints in EPTB cases. Other than culture, several other tests are available but their feasibility and effciacy for the detection of EPTB is still the matter of interest. We need more specific and precise test/s for the various forms of EPTB diagnosis which can easily be applied in the routine TB control program is required. A test that can contribute remarkably towards improving EPTB case detection reducing the morbidity and mortality is the utmost requirement. In this review we described the scenario of molecular and other noval methods available for laboratory diagnosis of EPTB, and also discussed the challenges linked with each diagnostic method. This review will make the readers aware of new emerging diagnostic techniques in the field of EPTB diagnosis. They can make an informed decision to choose the appropriate one according to the test availability, their clinical settings and financial considerations.

Clinical Application of the Mycobacterium tuberculosis-RNA Assay of Pericardial Tissue Specimens in the Diagnosis of Tuberculous Pericarditis

Purpose

To assess the accuracy of the Mycobacterium tuberculosis (MTB)-RNA assay using pericardial tissue specimens for tuberculous pericarditis (TBP) diagnosis.

Methods

MTB culture and MTB-RNA assay were performed for patients with suspected TBP. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the curve (AUC) of these two assays were analyzed.

Results

This study included 79 patients. The sensitivity, specificity, PPV, NPV, and AUC were 28.1% (18/64), 100.0% (15/15), 100.0% (18/18), 24.6% (15/61), and 0.64 for the MTB culture and 37.5% (24/64), 100.0% (15/15), 100.0% (24/24), 27.3% (15/55), and 0.69 for the MTB-RNA assay, respectively. Patients with positive pericardial tissue culture were defined as having definite TBP; in other words, culture was the gold standard for this group of patients and had a sensitivity, specificity, PPV, and NPV of 100% and an AUC of 1.00. However, these values were found to be 72.2% (13/18), 100.0% (15/15), 100.0% (13/13), 75.0% (15/20), and 0.86 for the MTB-RNA assay, respectively. Among patients with probable TBP (culture-negative patients), the sensitivity, specificity, NPV, and AUC of MTB culture were 0.0% (0/46), 100.0% (15/15), 24.6% (15/61), and 0.50, respectively, but the PPV could not be determined. These values were found to be 23.9% (11/46), 100.0% (15/15), 100.0% (11/11), 30.0% (15/50), and 0.62 for the MTB-RNA assay, respectively.

Conclusion

MTB-RNA assay using pericardial tissues had limited diagnostic efficacy for TBP. In culture-positive TBP, the diagnostic accuracy of MTB-RNA was good. In contrast, in culture-negative TBP, its diagnostic accuracy was unsatisfactory.