Nontuberculous mycobacterial pulmonary infection in patients with idiopathic interstitial pneumonias: comparison with patients without idiopathic interstitial pneumonias

Central Role of CT in Management of Pulmonary Fibrosis

With the approval of antifibrotic medications to treat patients with idiopathic pulmonary fibrosis and progressive pulmonary fibrosis, radiologists have an integral role in diagnosing these entities and guiding treatment decisions. CT features of early pulmonary fibrosis include irregular thickening of interlobular septa, pleura, and intralobular linear structures, with subsequent progression to reticular abnormality, traction bronchiectasis or bronchiolectasis, and honeycombing. CT patterns of fibrotic lung disease can often be reliably classified on the basis of the CT features and distribution of the condition. Accurate identification of usual interstitial pneumonia (UIP) or probable UIP patterns by radiologists can obviate the need for a tissue sample-based diagnosis. Other entities that can appear as a UIP pattern must be excluded in multidisciplinary discussion before a diagnosis of idiopathic pulmonary fibrosis is made. Although the imaging findings of nonspecific interstitial pneumonia and fibrotic hypersensitivity pneumonitis can overlap with those of a radiologic UIP pattern, these entities can often be distinguished by paying careful attention to the radiologic signs. Diagnostic challenges may include misdiagnosis of fibrotic lung disease due to pitfalls such as airspace enlargement with fibrosis, paraseptal emphysema, recurrent aspiration, and postinfectious fibrosis. The radiologist also plays an important role in identifying complications of pulmonary fibrosis-pulmonary hypertension, acute exacerbation, infection, and lung cancer in particular. In cases in which there is uncertainty regarding the clinical and radiologic diagnoses, surgical biopsy is recommended, and a multidisciplinary discussion among clinicians, radiologists, and pathologists can be used to address diagnosis and management strategies. This review is intended to help radiologists diagnose and manage pulmonary fibrosis more accurately, ultimately aiding in the clinical management of affected patients. ©RSNA, 2024 Supplemental material is available for this article.

Atypical presentation of nontuberculous mycobacterial pulmonary infection in a patient with interstitial lung abnormality: A case report

Nontuberculous mycobacterial (NTM) infection is a common and important cause of chronic pulmonary disease, typically characterized by fibrocavitary and nodular-bronchiectatic forms on computed tomography (CT) of the chest. Structural lung disease and the host’s immune status can affect NTM pulmonary infections. Herein, we report a rare case of an NTM pulmonary infection with multiple nodules and masses (with internal cavitation) in an immunocompetent patient exhibiting interstitial lung abnormality on a chest CT.

Comorbidities associated with nontuberculous mycobacterial disease in Japanese adults: a claims-data analysis

BACKGROUND

Nontuberculous mycobacterial (NTM) lung disease is one of a growing number of chronic health problems that is difficult to cure in aging societies. While it is important to be vigilant about associated comorbidities in order to provide better patient care, data on the prevalence of comorbidities stratified by country or region are scarce. We aimed to elucidate the comorbidities associated with NTM disease based on Japanese health insurance claims data.

METHODS

Cross-sectional analyses were performed using the claims data for 2014 provided by the Japan Medical Data Center Co., Ltd. Patients aged 20-75 years with ≥3 claims associated with NTM disease were identified and matched to 10 sex-and-age-matched controls that had never made a claim for NTM disease. Thirty-one comorbidities previously suspected to be associated with NTM disease were selected, and the prevalence of these comorbidities compared between cases and controls.

RESULT

Overall, 419 NTM patients (134 males and 285 females) and 4190 non-NTM controls were identified from the JMDC database. Aspergillosis, asthma, chronic heart failure, diffuse panbronchiolitis, gastroesophageal reflux, interstitial pneumonia, lung cancer, cancer other than breast, lung, ovary, or prostate cancer, and rheumatoid arthritis were associated with NTM disease in both males and females. Chronic obstructive pulmonary disease was associated with NTM in males while chronic kidney disease, osteoporosis, and Sjögren syndrome were associated with NTM in females.

CONCLUSION

NTM disease was associated with multiple comorbidities that should be considered when providing medical care to individuals with NTM disease.

Incidence and etiology of chronic pulmonary infections in patients with idiopathic pulmonary fibrosis

BACKGROUND

The incidence and etiologies of chronic pulmonary infection (CPI) in patients with idiopathic pulmonary fibrosis (IPF) have been poorly investigated.

METHODS

We conducted a retrospective study of 659 patients with IPF to assess the incidence, etiologies, and risk factors of CPI development. CPI was defined if the etiology of infection was diagnosed one or more months after the onset of symptoms or upon the appearance of new shadows on pulmonary radiological images.

RESULTS

At IPF diagnosis, 36 (5.5%) patients had CPI, and 46 (7.0%) patients without CPI at IPF diagnosis developed CPI over a median follow-up period of 6.1 years. The incidence density of CPI development was 18.90 cases per 1000 person-years. Detected organisms from these 46 patients were Mycobacterium avium complex in 20 patients, other nontuberculous mycobacteria in 4, M. tuberculosis in 7, Aspergillus spp. in 22, and Nocardia sp. in one. In a multivariate Cox regression hazard model, PaO2 <70 Torr and KL-6 ≥2000 U/mL were associated with CPI development.

CONCLUSIONS

Nontuberculous mycobacteria, M. tuberculosis, and Aspergillus and Nocardia spp. were the four most frequent etiologies of CPI in patients with IPF. During follow-up of IPF, clinicians should pay attention to the development of CPI, especially in patients with PaO2 <70 Torr or KL-6 ≥2000 U/mL.

Application of diagnostic criteria for non-tuberculous mycobacterial disease to a case series of mycobacterial-positive isolates

The American Thoracic Society (ATS) and Infectious Diseases Society of America (IDSA) have provided guidelines to assist in the accurate diagnosis of lung disease caused by nontuberculous mycobacteria (NTM). These microbiologic, radiographic, and clinical criteria are considered equally important and all must be met to make the diagnosis of NTM lung disease. To assess the significance of the three criteria, each was evaluated for its contribution to the diagnosis of NTM lung disease in a case series. Laboratory reports of any specimen positive for NTM isolation were collected between January 1, 2006 and December 31, 2010 at a university medical center. Medical records were reviewed in detail using a standardized form. The total number of patients with a culture from any site positive for NTM was 297 while the number from respiratory specimens during the same period was 232 (78%). Samples from two of these patients also yielded M. tuberculosis complex and were excluded. While 128 of the remaining 230 patients (55.7%) in the cohort met the microbiologic criterion for diagnosis of NTM lung disease, 151 (65.6%) and 189 (78.3%) met the radiologic and clinical criteria respectively. Only 78 patients (33.9%) met all three criteria provided by the ATS/IDSA for diagnosis of NTM lung disease. This evaluation reaffirms that defining NTM lung disease using either one or two of the criteria provided by the 2007 ATS/IDSA guidelines may significantly overestimate the number of cases of NTM lung disease. Based on the experience of defining NTM lung disease in this case series, recommendations for modification of the ATS/IDSA guidelines are provided which include expansion of both radiologic patterns and the list of symptoms associated with NTM lung disease.

Clinical and radiological features of pulmonary tuberculosis in patients with idiopathic pulmonary fibrosis

BACKGROUND

Data regarding the radiological and clinical features of pulmonary tuberculosis (PTB) in patients with idiopathic pulmonary fibrosis (IPF) are limited. Accordingly, the aim of this study was to investigate the clinico-radiological features of PTB in patients with IPF.

METHODS

Clinico-radiological variables were retrospectively compared between PTB patients with and without IPF (TB-IPF and TB-control, respectively), and computed tomography (CT) findings were compared between the TB-IPF group and patients with nontuberculous mycobacterial lung disease and IPF (NTM-IPF).

RESULTS

Of 609 IPF patients, 28 (4.6%) were diagnosed with PTB. In the TB-IPF group, incidental radiological finding was the most common presenting manifestation, and the rate of treatment success was significantly lower than in the TB-control group. On CT scan, the typical locations of reactivated PTB were significantly less often involved in the TB-IPF group than in the TB-control group. The TB-IPF group exhibited a significantly lower frequency of centrilobular nodules and a higher rate of consolidation-predominant pattern than did the TB-control group. CT findings in the TB-IPF group were similar to those in the NTM-IPF group.

CONCLUSIONS

Incidental radiological findings were the most common presenting manifestations in TB-IPF patients, who were more likely to present with atypical PTB manifestations on CT scan and who experienced poorer treatment outcomes.

Clinicoradiological Features of Pulmonary Tuberculosis with Interstitial Pneumonia

Objective Although rare, pulmonary tuberculosis occasionally develops in patients with interstitial pneumonia (IP). In this study, we aimed to evaluate the clinicoradiological features of pulmonary tuberculosis associated with IP. Methods In this retrospective, observational, single-center study, the medical charts, high-resolution computed tomography (HRCT) findings, and bacteriological test results of patients with IP who also tested positive for Mycobacterium tuberculosis were reviewed. Patients The study included 20 patients with IP out of 329 who tested positive for M. tuberculosis in sputum or bronchoalveolar lavage fluid cultures at Toranomon Hospital between January 2006 and December 2017. Results The HRCT patterns were usual interstitial pneumonia (UIP) in 11 patients and non-UIP in 9 patients. Consolidations (80%) were the most frequent HRCT findings, followed by cavities (60%) and nodules (45%), which are generally characteristic of pulmonary tuberculosis. Consolidations often developed in relation to fibrotic or emphysematous lesions. Tuberculosis lesions could not be identified in one patient. All patients were treated with anti-tuberculosis drugs according to WHO guidelines, and 13 patients achieved a WHO category of "Treatment success." No patient died of tuberculosis, and the median survival time for the 20 patients was 1,196 days. Conclusion Although the HRCT findings for pulmonary tuberculosis associated with IP are atypical, appropriate tuberculosis treatments can lead to favorable outcomes.

Natural history of Mycobacterium avium complex lung disease in untreated patients with stable course

Little is known about the long-term natural history of Mycobacterium avium complex lung disease (MAC-LD) in untreated patients with stable course.The aim of this study was to investigate the natural course of untreated stable MAC-LD, with a focus on factors associated with clinical deterioration, spontaneous sputum conversion and prognosis.Of 488 patients diagnosed with MAC-LD between 1998 and 2011, 305 patients (62.5%) showed progressive MAC-LD resulting in treatment initiation within 3 years of diagnosis and 115 patients (23.6%) exhibited stable MAC-LD for at least 3 years with a median follow-up duration of 5.6 years. Patients with stable MAC-LD were more likely to have higher body mass index and less systemic symptoms at initial diagnosis compared with patients with progressive MAC-LD, while positive sputum acid-fast bacilli smear, fibrocavitary type and more extensive disease in radiological findings were more associated with progressive MAC-LD. Of the untreated patients with stable MAC-LD, 51.6% underwent spontaneous sputum conversion, with younger age, higher body mass index and negative sputum acid-fast bacilli smear at initial diagnosis found to be predictors of this occurrence.Advanced age, fibrocavitary type and abnormal pulmonary function were negative prognostic factors for survival in patients with stable MAC-LD.

Newly detected pulmonary nontuberculous mycobacterial infection and peripheral lung cancers in patients during follow-up of idiopathic interstitial pneumonia: comparison of CT findings

This article describes the difference between the computed tomography (CT) findings in patients with newly detected pulmonary nontuberculous mycobacterial infection (NTM-IIP) and Cancer-IIP. We retrospectively evaluated 35 NTM-IIP and 78 Cancer-IIP patients in reference to their null idiopathic interstitial pneumonia CT (n = 113), using >10 years of data. Two independent radiologists analyzed the CT characteristics and the axial location of the main opacity. The interobserver agreement was good (κ > 0.771). The NTM-IIP patients were older (P = 0.034). The median size of the main opacity in the NTM-IIP (27 mm; 11-73) was larger (19 mm; 5-60; P = 0.002). Consolidation (n = 30; 85.7%; odds ratio [OR], 45) and cavities (n = 14; 40%, OR, 25) were more common in NTM-IIP (all P < 0.001). The midst of the fibrotic cysts including honeycomb cysts (n = 16; 45.7%, OR, 4.95) was more common in NTM-IIP (P = 0.006). NTM-IIP appeared larger, with more frequent consolidation and cavities, and was more likely to have been located in the midst of the fibrotic cysts including honeycomb cysts at the CT, which showed that it was older than Cancer-IIP.