Clinical Features and Prognosis of Nontuberculous Mycobacterial Pleuritis: A Multicenter Retrospective Study

Predictive risk factors of treatment-refractory Mycobacterium avium complex lung disease: a single-center retrospective cohort study

Background

Mycobacterium avium complex lung disease (MAC-LD) is a chronic, progressive, potentially life-threatening infection. Some cases are refractory to standard guideline-based therapy (GBT), and sputum cultures are persistently positive for acid-fast bacilli. Although an early identification of treatment-refractory MAC-LD is crucial, its risk factors remain unknown.

Objectives

We aimed to identify the risk factors for refractory MAC-LD in response to initial GBT.

Design

A retrospective single-center study was conducted involving consecutive patients with MAC-LD who were diagnosed between 2006 and 2024 and received initial GBT.

Methods

Refractory MAC-LD was defined as sputum culture positivity at least 6 months after the initial GBT. Prognostic factors were identified using Cox proportional hazards analysis, and risk factors for refractory MAC-LD were examined using logistic regression analysis.

Results

Of the 201 patients with definite MAC-LD, 35 (17.4%) had refractory MAC-LD. Patients with refractory MAC-LD had a significantly lower body mass index (BMI), more cavitary lesions on high-resolution computed tomography (HRCT), and higher mortality (log-rank test, p = 0.006) compared to those with non-refractory MAC-LD. A multivariate analysis adjusted for age and sex showed that refractory MAC-LD (adjusted hazard ratio (HR): 2.76; 95% confidence interval (CI): 1.10-6.95; p = 0.030) and cavitary lesions on HRCT (adjusted HR: 2.77; 95% CI: 1.34-5.70; p = 0.005) were significantly associated with all-cause mortality. In addition, a multivariate analysis revealed that lower BMI (odds ratio (OR): 0.68; 95% CI: 0.55-0.85; p < 0.001) and cavitary lesions on HRCT (OR: 2.52; 95% CI: 1.15-5.50; p = 0.020) were independent risk factors of refractory MAC-LD.

Conclusion

Low BMI and cavitary lesions on HRCT are risk factors for refractory MAC-LD.

A Systematic Review of Factors Associated with Mortality among Patients with Mycobacterium avium Complex Lung Disease

PURPOSE

As the number of patients with Mycobacterium avium complex lung disease is significantly increasing worldwide, several studies have focused on the prognostic factors associated with the disease. This systematic review investigated the factors associated with mortality among patients with Mycobacterium avium complex lung disease.

METHODS

Two investigators independently identified studies that were designed to determine risk factors for mortality in patients with Mycobacterium avium complex lung disease from PubMed, the Cochrane Register of Control Trial database, and EMBASE (accessed on 25 November 2022).

RESULTS

Of the 1133 titles and abstracts screened, 54 full texts were selected for review, and 15 studies were finally included in this systematic review. The most commonly studied risk factors were advanced age and low body mass index (11 studies for each), followed by male sex (8 studies), hypoalbuminemia (5 studies), and cavity (5 studies). In each study, these factors were mostly associated with increased all-cause mortality among patients with Mycobacterium avium complex lung disease as confirmed via multivariate analysis.

CONCLUSIONS

Advanced age, male sex, low body mass index, hypoalbuminemia, and cavity are likely to be the common risk factors for all-cause mortality among patients with Mycobacterium avium complex lung disease, suggesting that patients with these factors need to be carefully monitored.

Longitudinal significance of six-minute walk test in patients with nontuberculous mycobacterial pulmonary disease: an observational study

BACKGROUND

The long-term exercise tolerance changes in patients with nontuberculous mycobacterial pulmonary disease (NTM-PD) are of great interest because of its chronic course. This study aimed to characterize the associations between changes over time in six-minute walking test (6MWT) parameters and clinical parameters in patients with NTM-PD.

METHODS

Overall, 188 patients with NTM-PD, visiting outpatient clinics at Keio University Hospital from April 2012 to March 2020 were included in the study. Data were collected using the St. George's Respiratory Questionnaire (SGRQ), pulmonary function test (PFT), blood tests, and the 6MWT at registration and at least once after that. The association of the anchors and clinical indicators with the 6MWT parameters was assessed.

RESULTS

The median age [interquartile range] of the patients was 67 [63-74] years. The median baseline six-minute walk distance (6MWD) and final Borg scale (FBS) were 413 [361-470] m and 1 [0-2], respectively. In the correlation analysis, ΔSGRQ total/year (yr), Δforced vital capacity (FVC, % predicted)/yr, Δforced expiratory volume in 1 s (FEV₁, % predicted)/yr, and Δdiffusing capacity for carbon monoxide (DL_CO, % predicted)/yr correlated with both Δ6MWD/yr and ΔFBS/yr in the longitudinal analysis (|Rho| > 0.20). When stratified into three quantiles of changes in each anchor, the 6MWT parameters worsened over time in the bottom 25% group by mixed-effects model. Specifically, Δ6MWD was affected by SGRQ activity, SGRQ impacts, PFT (FVC, FEV₁, and DL_CO), and C-reactive protein (CRP). ΔFBS was affected by all SGRQ components, total score, and PFT. Anchor scores and variables at baseline that worsened Δ6MWD were higher SGRQ scores, lower FVC (% predicted), lower DL_CO (% predicted), higher Krebs von den Lungen-6, old age, and undergoing treatment at registration. Similarly, these clinical parameters and elevated CRP, excluding undergoing treatment at registration, worsened ΔFBS.

CONCLUSIONS

The decreased walking distance and exacerbation of dyspnea on exertion over time in patients with NTM-PD may reflect a deterioration of health-related quality of life and pulmonary function. Thus, the change in 6MWT over time can be used as an indicator to accurately assess the patient's condition and tailor their healthcare environment.

Nontuberculous mycobacteria infections of the pleura: A systematic review

BACKGROUND

Nontuberculous mycobacterial (NTM) pleuritis is an uncommon manifestation of NTM infection. Case reports and small case series have shown a variable clinical course and high mortality rates.

OBJECTIVE

To describe patients' characteristics, clinical presentation and outcomes of NTM pleural infections.

METHODS

A systematic review of cases of NTM pleural infections published in PubMed-indexed journals from 1980 to 2021.

RESULTS

A total of 206 cases of NTM pleural infections were found and analyzed. Fifty-eight percent of cases were males. The mean age was 57.5 yrs (range 9-87 yrs). Forty-three percent of patients were immunosuppressed, and 43% had a chronic lung disease; thirty-two percent had neither risk factor. In addition to the pleural infection, 67% of cases had a concurrent pulmonary NTM infection, and in 18 cases there was another extrapulmonary site of NTM infection. In 29% of cases the pleural infection was the sole manifestation of NTM disease. The most common isolated mycobacterium was Mycobacterium avium complex (65%). Fifty-three percent and 26% of patients required pleural effusion drainage and a surgical intervention, respectively, to treat the infection, in addition to anti-NTM chemotherapy. Forty percent of patients developed pneumothorax, 16% suffered from empyema, and 16.5% had broncho-pleural fistula. The reported mortality rate was 24%.

CONCLUSION

NTM pleural infections may arise in immunocompetent and immunosuppressed patients, with or without chronic lung disease or concurrent NTM pulmonary infection. These infections carry a poor prognosis and a high risk of complications requiring surgical interventions in addition to anti-NTM chemotherapy.

Mycobacterium avium Pleurisy with Bronchopleural Fistula Resulting in Rapidly Progressive Respiratory Failure Diagnosed by Transbronchial Autopsy: A Case Report

Nontuberculous mycobacterial lung disease usually manifests as a chronic pulmonary infection. We herein report a fatal case of Mycobacterium avium pleurisy in a man with a refractory bronchopleural fistula that led to rapidly progressive pneumonia. A post-mortem transbronchial biopsy was performed. Histopathology revealed an acute lung injury pattern and epithelioid granulomas. Variable number tandem repeat analyses and drug susceptibility testing revealed Mycobacterium avium had acquired macrolide resistance during chemotherapy with rifampicin, ethambutol, and clarithromycin. Clinicians should be aware that Mycobacterium avium pleurisy with bronchopleural fistula can lead to fatal pneumonia, especially in patients with persistently positive cultures despite multidrug treatment.

Pleurisy with pneumothorax due to CAM-resistant MAC lung disease

A 72-year-old man received rifampicin, ethambutol and sitafloxacin to treat clarithromycin (CAM)-resistant Mycobacterium avium complex (MAC) lung disease. He was admitted because of fever. Pneumothorax and pleural effusion were present in the right lung, and a new consolidation appeared in the right upper lobe. Based on positive culture of the pleural effusion for CAM-resistant M. avium and findings on chest computed tomography, he was diagnosed with pleurisy due to M. avium, with rupture of the subpleural lung parenchymal lesion into the pleural space. Additional treatment with streptomycin (SM) improved the patient's high-grade fever. SM might be effective for pleurisy caused by CAM-resistant MAC lung disease.

Pleuritis due to Mycobacterium xenopi without pulmonary infection

Nontuberculous mycobacteria (NTM) may cause pulmonary and extra-pulmonary disease in both immunocompetent and immunocompromised patients. Pleuritis is an uncommon manifestation on NTM disease, and pleuritis caused by Mycobacterium xenopi has only been described once before. Because it is considered to be an environmental contaminant, isolation of M. xenopi from bronchopulmonary secretions or other sites is often dismissed. The disease caused by M. xenopi is usually a pulmonary infection and typically occurs in severely immunocompromised individuals or in immunocompetent patients with an underlying chronic lung disease. We describe an unusual case of pleuritis caused by M. xenopi in a patient without an underlying chronic lung disease and with no evidence of a concurrent M. xenopi pulmonary infection.

Development of Rheumatoid Arthritis in Cavitary Mycobacterium avium Pulmonary Disease: A Case Report of Successful Treatment with CTLA4-Ig (Abatacept)

Background

Nontuberculous mycobacterial pulmonary disease (NTM-PD) often develops in patients with rheumatoid arthritis (RA), especially during immunosuppressive treatment, including biological disease-modifying antirheumatic drugs. NTM-PD is associated with airway lesions such as bronchiectasis, which is frequently seen in RA patients. Distinguishing which diseases cause the pulmonary lesion is difficult. However, there are limited reports of the development of RA during the follow-up of NTM-PD and how biological agents should be administered in these conditions, especially with cavitary lesions.

Case Presentation

A 62-year-old woman with hemosputum was referred to our hospital, where she was diagnosed with Mycobacterium avium pulmonary disease. She began treatment with several antibiotics, including clarithromycin, ethambutol, rifampicin, and amikacin. In the course of treatment, M. avium became macrolide-resistant. Five years after beginning antibiotic treatment, she felt arthralgia in the fingers and wrists and had a high titer of rheumatoid factor and anticitrullinated peptide antibody, with which we diagnosed RA. Methotrexate, prednisolone, and iguratimod were subsequently administered, but the activity of RA gradually worsened. Meanwhile, M. avium changed to a macrolide-susceptible strain, her sputum smear results remained almost negative, and the NTM-PD disease was well controlled with antimicrobial therapy, despite her having cavitary lesions. Therefore, we started using CTLA4-Ig (abatacept). RA symptoms were substantially ameliorated. The pulmonary lesions and NTM-PD worsened mildly, but her pulmonary symptoms were stable.

Conclusion

Physicians should be mindful of the etiologies of bronchiectasis, including RA, even in patients with a long-term history of treatment for bronchiectasis and NTM-PD. When NTM-PD is well controlled, even with remaining cavitary lesions, abatacept may be an option for patients with RA based on a comprehensive assessment of disease progression using NTM sputum smear/culture, computed tomography findings, and treatment response.