Elicker, Brett M.

Abstract Rationale Mucus plugs occur in chronic obstructive pulmonary disease (COPD), but little is known about their size and airway location or whether these mucus plug features change as emphysema worsens. Methods Computed tomographic lung scans from 31 participants with COPD from the SubPopulations and InteRmediate Outcomes In COPD Study (SPIROMICS) cohort were analyzed to quantify mucus plug size and airway location and extent of emphysema. Radiologist annotations of mucus plugs were incorporated in an image processing pipeline to generate size and location information. Emphysema was quantified as the percentage of voxels less than -950 Hounsfield units. Measurements and Main Results The length distribution of 563 annotated mucus plugs varied from 2 to 50 mm. The distribution was multimodal, and an 11-mm length defined short (“stubby,” ≤11 mm) and long (“stringy,” >11 mm) plug phenotypes, with stubby plugs being most common (64%). Mucus plugs localized predominantly to airway generations 6 to 9, and their prevalence was highest in lower lobes. On a lobar basis, the mucus plug number decreased as emphysema percentage increased, whereas average mucus plug volume tended to increase. Conclusion COPD is characterized by mucus plugs of varying size and shape, and emphysematous lung regions may be differentially susceptible to formation of these plugs. The location of mucus plugs in segmental and subsegmental airways in COPD makes them amenable to treatment with inhaled medications or bronchoscopy.

Context.— Idiopathic pulmonary fibrosis (IPF) is a distinctive clinicopathologic entity and the most common form of progressive diffuse lung scarring in older adults. Idiopathic pulmonary fibrosis manifests histopathologically as the usual interstitial pneumonia pattern. The usual interstitial pneumonia pattern is distinguished by geographically and temporally heterogeneous fibrosis that is peripherally accentuated, often with honeycombing and traction bronchiectasis. Idiopathic pulmonary fibrosis is not the only disease that leads to end-stage lung fibrosis, however, and several other entities may also cause advanced fibrosis. Surgical lung biopsies often present a diagnostic dilemma when they show clear evidence of advanced fibrosis, but the clinical, imaging, and/or histopathologic subcharacteristics suggest something other than IPF. Objective.— To address this dilemma, we review several other fibrotic lung diseases, including connective tissue disease–associated interstitial lung disease, chronic hypersensitivity pneumonitis, advanced pulmonary Langerhans cell histiocytosis, end-stage pulmonary sarcoidosis, Erdheim-Chester disease, Hermansky-Pudlak syndrome, and others, detailing their clinical, radiologic, and histopathologic attributes and emphasizing similarities to and differences from IPF. Data Sources.— Data sources comprised published peer-reviewed literature and personal experience of the authors. Conclusions.— Often, clues in the lung biopsy may offer the first suggestion of a fibrotic lung disease other than IPF, and accurate classification is important for prognosis, treatment, and the development of future therapies.

Abstract Rationale Gastroesophageal reflux (GER) is highly prevalent in patients with idiopathic pulmonary fibrosis (IPF). Chronic microaspiration secondary to GER may play a role in the pathogenesis and natural history of IPF. Objectives To investigate the relationship between GER-related variables and survival time in patients with IPF. Methods Regression analysis was used to investigate the relationship between GER-related variables and survival time in a retrospectively identified cohort of patients with well-characterized IPF from two academic medical centers. Measurements and Main Results Two hundred four patients were identified for inclusion. GER-related variables were common in this cohort: reported symptoms of GER (34%), a history of GER disease (45%), reported use of GER medications (47%), and Nissen fundoplication (5%). These GER-related variables were significantly associated with longer survival time on unadjusted analysis. After adjustment, the use of GER medications was an independent predictor of longer survival time. In addition, the use of gastroesophageal reflux medications was associated with a lower radiologic fibrosis score. These findings were present regardless of center. Conclusions The reported use of GER medications is associated with decreased radiologic fibrosis and is an independent predictor of longer survival time in patients with IPF. These findings further support the hypothesis that GER and chronic microaspiration may play important roles in the pathobiology of IPF.

A tomografia de alta resolução (TCAR) é a técnica de imagem radiológica que reflete mais de perto as alterações da estrutura pulmonar. Os vários achados tomográficos podem ser combinados para formar padrões típicos. Estes, conjuntamente com a distribuição anatômica dos achados, e com os dados clínicos, podem estreitar o diagnóstico das doenças intersticiais pulmonares difusas, e em vários casos sugerir o diagnóstico correto com alto grau de acurácia. Os padrões mais comuns das doenças intersticiais pulmonares difusas na TCAR são o nodular, linear e reticular, lesões císticas, opacidades em vidro fosco e consolidações. Este artigo revisa as correlações entre os padrões tomográficos na TCAR e os achados patológicos e resume as causas mais comuns e os métodos de investigação para se atingir um diagnóstico nas doenças pulmonares crônicas difusas mais comuns.