Predictive factors for tuberculosis in patients with a TB-PCR-negative bronchial aspirate

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.

Radiologic and laboratory differences in patients with tuberculous and parapneumonic pleural effusions showing non-lymphocytic predominance and high adenosine deaminase levels

PURPOSE

Tuberculous pleural effusion (TPE) is characterized by lymphocytic predominance and high adenosine deaminase (ADA) levels. However, TPEs sometimes present non-lymphocytic predominance, and parapneumonic effusion (PPE) often exceeds the cutoff value of ADA for TPE. Thus, the differential diagnosis of cases with pleural fluid (PF) showing non-lymphocytic predominance and high ADA levels is challenging. However, limited data concerning the clinical differences in these patients are available.

METHODS

A retrospective study was conducted on TPE and PPE patients with PF showing non-lymphocytic predominance and ADA levels ≥40 U/L in 2009-2013 in a South Korean tertiary referral hospital. The clinical, laboratory, and computed tomography (CT) findings between the groups were analyzed using multivariate logistic regression to develop a prediction model with independent factors for TPE.

RESULTS

Among 353 patients with TPE, 24 (6.8 %) showed PF with non-lymphocytic predominance and ADA levels of ≥40 U/L. Twenty-eight PPE patients who presented PF findings comparable with those of TPE patients were included in the control group. In the final analysis, PF ADA levels >58 U/L and nodular lung lesions on CT were independent positive predictors, while loculated effusion was an independent negative predictor for TPE. Using the prediction model, a score ≥ +3 provided a sensitivity of 88 %, specificity of 93 %, positive predictive value of 91 %, and negative predictive value of 90 % for TPE.

CONCLUSION

PF ADA levels, nodular lung lesions, and loculated pleural effusion may help differentiate TPE from PPE in patients with PF showing non-lymphocytic predominance and ADA levels ≥40 U/L.

Extra-pulmonary tuberculosis: a biomarker analysis

INTRODUCTION

Studies on biomarkers in tuberculosis are focused on pulmonary forms of this disease (PTB), and only limited information is currently available on biomarkers of extra-pulmonary tuberculosis (EPTB).

METHODS

Serum samples from 24 patients with PTB, 29 patients with EPTB and 27 healthy controls were obtained, and the levels of interferon-gamma, chemokine ligand 9, mannose-binding lectin (MBL), tumor marker Ca-125 and adenosine deaminase were determined.

RESULTS

The circulating levels of all tested biomarkers in the serum were significantly higher in PTB and EPTB patients than in controls. However, there were no significant differences in the levels of the biomarkers between patients with PTB and EPTB, with the exception of serum levels of MBL which were significantly higher in patients with EPTB than in patients with PTB (p = 0.01). In patients with EPTB, no significant differences were observed in biomarker levels among patients with or without concomitant PTB involvement. Based on MBL serum levels, ROC curve analysis showed an AUC of 0.85 for EPTB versus non-EPTB. The optimal cut-off value of MBL serum levels for EPTB versus non-EPTB was 1,000 μg/ml, with a sensitivity and specificity of 79.3 and 78.0 %, respectively.

CONCLUSIONS

Biomarkers usually present as acute phase reactants and do not enable pulmonary forms to be differentiated from more serious or extra-pulmonary forms. MBL may be an exception.

Tuberculous peritonitis with infracarinal mass and elevated CA-125 in a 13-year-old girl

A 13-year-old girl with weight loss and ascites was admitted with suspicion of a malignant disease. Abdominal magnetic resonance imaging indicated extensive peritonitis and showed no evidence of a solid tumor. As a new imaging observation, thoracic computed tomography showed a lymphoma-like infracarinal mass and further enlarged lymph nodes in the pathway of draining lymph ducts. A tuberculin skin test and an interferon-gamma blood test were positive, and the tumor marker CA-125 was elevated. Histology of a peritoneal biopsy showed infectious granulomas with central necrosis, and Mycobacterium tuberculosis could be cultured, leading to the diagnosis of a tuberculous peritonitis. The girl received multi-drug anti-tuberculous treatment and subsequently recovered. At follow-up the peritonitis and the infracarinal mass had vanished. In conclusion, tuberculous peritonitis is a rare but relevant differential diagnosis in peritonitis of unknown origin. Its diagnosis is facilitated by imaging, by tuberculosis skin and blood tests, and by clinical interpretation.