Radiological versus histological diagnosis in UIP and NSIP: survival implications

Possible UIP pattern on high-resolution computed tomography is associated with better survival than definite UIP in IPF patients

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a progressive fibrosing lung disease of unknown etiology. Inter-society consensus guidelines on IPF diagnosis and management outline radiologic patterns including definite usual interstitial pneumonia (UIP), possible UIP, and inconsistent with UIP. We evaluate these diagnostic categories as prognostic markers among patients with IPF.

METHODS

Included subjects had biopsy-proven UIP, a multidisciplinary team diagnosis of IPF, and a baseline high-resolution computed tomography (HRCT). Thoracic radiologists assigned the radiologic pattern and documented the presence and extent of specific radiologic findings. The outcome of interest was lung transplant-free survival.

RESULTS

IPF patients with a possible UIP pattern on HRCT had significantly longer Kaplan-Meier event-free survival compared to those with definite UIP pattern (5.21 and 3.57 years, respectively, p = 0.002). In a multivariable Cox proportional hazards model adjusted for baseline age, gender, %-predicted FVC, and %-predicted DLCO via the GAP Stage, extent of fibrosis (via the traction bronchiectasis score) and ever-smoker status, possible UIP pattern on HRCT (versus definite UIP) was associated with reduced hazard of death or lung transplant (HR = 0.42, CI 95% 0.23-0.78, p = 0.006).

CONCLUSIONS

Radiologic diagnosis categories outlined by inter-society consensus guidelines is a widely-reported and potentially useful prognostic marker in IPF patients, with possible UIP pattern on HRCT associated with a favorable prognosis compared to definite UIP pattern, after adjusting for relevant covariates.

Diagnosis of Idiopathic Pulmonary Fibrosis "Pragmatic Challenges in Clinical Practice"

The past few years have signaled a major breakthrough on the management of idiopathic pulmonary fibrosis (IPF). Finally, we have drugs in our arsenal able to slow down the inexorable disease natural course. On the other hand, the latter evidence has increased the responsibility for a timely and accurate diagnosis. Establishment of IPF diagnosis directly affects the choice of appropriate treatment. The current diagnostic guidelines represent a major step forward providing an evidence-based road map; yet, clinicians are encountering major diagnostic dilemmas that inevitably affect therapeutic decisions. This review article aims to summarize the current state of knowledge on the diagnostic procedure of IPF based on the current guidelines and discuss pragmatic difficulties and challenges encountered by clinicians with regards to their applicability in the everyday clinical practice.

Evaluating disease severity in idiopathic pulmonary fibrosis

Accurate assessment of idiopathic pulmonary fibrosis (IPF) disease severity is integral to the care provided to patients with IPF. However, to date, there are no generally accepted or validated staging systems. There is an abundance of data on using information acquired from physiological, radiological and pathological parameters, in isolation or in combination, to assess disease severity in IPF. Recently, there has been interest in using serum biomarkers and computed tomography-derived quantitative lung fibrosis measures to stage disease severity in IPF. This review will focus on the suggested methods for staging IPF, at baseline and on serial assessment, their strengths and limitations, as well as future developments.

Serological and morphological prognostic factors in patients with interstitial pneumonia with autoimmune features

Background

To identify the prognostic factors for survival in patients with interstitial pneumonia with autoimmune features (IPAF) who meet the serological domain of the IPAF criteria.

Methods

We retrospectively analysed 99 IPAF patients who met the serological domain and were hospitalised at the Respiratory Medicine Unit of Kurashiki Central Hospital from 1999 to 2015. The high-resolution computed tomography findings were usual interstitial pneumonia (UIP; n = 1), non-specific interstitial pneumonia (NSIP; n = 63), NSIP with organizing pneumonia (OP) overlap (n = 15), and OP (n = 20). One patient who had radiological UIP pattern, and met the serological and clinical domains was excluded. The clinical characteristics, radiological findings, administered therapy, and prognosis of the remaining 98 IPAF patients who met the serological and morphological domains were analysed.

Results

The median age of the 98 IPAF patients was 68 years, and 41 (41.8%) of them were men. Twelve (12.2%) of the 98 IPAF patients developed other characteristics and were diagnosed with connective tissue disease (CTD) later during the median follow-up of 4.5 years. Univariate Cox analysis revealed systemic sclerosis (SSc)-specific and SSc-associated antibodies (ANA nucleolar pattern, ANA centromere pattern, anti-ribonucleoprotein and anti-Scl-70) positive IPAF, radiological NSIP pattern, bronchoalveolar lavage fluid lymphocytes >15%, and age as significant prognostic factors for survival. Multivariate Cox analysis revealed radiological NSIP pattern (hazard ratio [HR], 4.48; 95% confidence interval [CI], 1.28–15.77, p = 0.02) and age (HR, 1.07; 95% CI, 1.02–1.11, p = 0.01) were significantly associated with worse survival.

Conclusions

We confirmed that radiological NSIP pattern and age are poor prognostic factors for the survival of IPAF patients. This study suggested that the autoantibodies that are highly specific for certain connective tissue diseases might be less important for the prognosis of IPAF compared with the radiological-pathological patterns. The relatively high proportion of IPAF patients who developed CTD later suggests the importance of careful observation for evolution to CTD in IPAF.

Idiopathic Pulmonary Fibrosis: A Genetic Disease That Involves Mucociliary Dysfunction of the Peripheral Airways

Idiopathic pulmonary fibrosis (IPF) is an incurable complex genetic disorder that is associated with sequence changes in 7 genes (MUC5B, TERT, TERC, RTEL1, PARN, SFTPC, and SFTPA2) and with variants in at least 11 novel loci. We have previously found that 1) a common gain-of-function promoter variant in MUC5B rs35705950 is the strongest risk factor (genetic and otherwise), accounting for 30-35% of the risk of developing IPF, a disease that was previously considered idiopathic; 2) the MUC5B promoter variant can potentially be used to identify individuals with preclinical pulmonary fibrosis and is predictive of radiologic progression of preclinical pulmonary fibrosis; and 3) MUC5B may be involved in the pathogenesis of pulmonary fibrosis with MUC5B message and protein expressed in bronchiolo-alveolar epithelia of IPF and the characteristic IPF honeycomb cysts. Based on these considerations, we hypothesize that excessive production of MUC5B either enhances injury due to reduced mucociliary clearance or impedes repair consequent to disruption of normal regenerative mechanisms in the distal lung. In aggregate, these novel considerations should have broad impact, resulting in specific etiologic targets, early detection of disease, and novel biologic pathways for use in the design of future intervention, prevention, and mechanistic studies of IPF.

Pulmonary fibrosis, part I: epidemiology, pathogenesis, and diagnosis

INTRODUCTION

Many forms of interstitial lung disease (ILD) can progress to extensive fibrosis and respiratory failure. Idiopathic pulmonary fibrosis (IPF), which generally has a poor prognosis, has been thoroughly studied over the past two decades, and many important discoveries have been made that pertain to genetic predisposition, epidemiology, disease pathogenesis, diagnosis, and management. Additionally, non-IPF forms of ILD can have radiologic and histopathologic manifestations that mimic IPF, and making an accurate diagnosis is key to providing personalized medicine to patients with pulmonary fibrosis. Areas covered: This manuscript discusses current knowledge pertaining to the genetics, epidemiology, pathogenesis, and diagnosis of pulmonary fibrosis with an emphasis on IPF. The material upon which this discussion is based was obtained from various published texts and manuscripts identified via literature searching (e.g. PubMed). Expert commentary: Many genetic variants have been identified that are associated with risk of developing pulmonary fibrosis, and an improved understanding of the influence of both genomic and epigenomic factors in the development of pulmonary fibrosis is rapidly evolving. Because many forms of fibrosing ILD can have similar radiologic and histopathologic patterns yet have different responses to therapeutic interventions, making an accurate diagnosis of specific forms of pulmonary fibrosis is increasingly important.

High resolution computed tomography pattern of usual interstitial pneumonia in rheumatoid arthritis-associated interstitial lung disease: Relationship to survival

PURPOSE

Interstitial lung disease is a common extra-articular manifestation of rheumatoid arthritis (RA-ILD) and is associated with significant morbidity and mortality. However, limited data exist regarding predictors of mortality. We sought to examine the prognostic value of the high-resolution computed tomography (HRCT) patterns in patients with RA-ILD.

MATERIALS AND METHODS

RA-ILD patients with HRCT patterns of usual interstitial pneumonia (UIP) or nonspecific interstitial pneumonia (NSIP) were identified among a longitudinal cohort of individuals evaluated at National Jewish Health. A total of 158 subjects were included in the study. For each subject, the earliest available HRCT was reviewed independently by two expert thoracic radiologists blinded to clinical data. HRCT patterns were classified as demonstrating definite UIP, possible UIP, or NSIP. Kaplan-Meier curves were generated and survival was compared among the three patterns using a log rank test for trend.

RESULTS

One hundred subjects (63%) had HRCT findings classified as definite UIP, 23 (15%) as possible UIP and 35 (22%) as NSIP. No difference in survival was seen between subjects with definite UIP versus those with possible UIP. The combined group of subjects with either definite- or possible UIP had significantly worse survival than those with NSIP (log-rank p = 0.03).

CONCLUSIONS

In patients with RA-ILD, patients with either definite UIP or possible UIP have equally poor survival when compared to those with an NSIP pattern.

CT Findings, Radiologic-Pathologic Correlation, and Imaging Predictors of Survival for Patients With Interstitial Pneumonia With Autoimmune Features

OBJECTIVE

The objective of this study is to determine the CT findings and patterns of interstitial pneumonia with autoimmune features (IPAF) and to assess whether imaging can predict survival for patients with IPAF.

MATERIALS AND METHODS

The study included 136 subjects who met the criteria for IPAF and had diagnostic-quality chest CT scans obtained from 2006 to 2015; a total of 74 of these subjects had pathologic samples available for review within 1 year of chest CT examination. CT findings and the presence of an usual interstitial pneumonitis (UIP) pattern of disease were assessed, as was the UIP pattern noted on pathologic analysis. Analysis of chest CT findings associated with survival was performed using standard univariate and multivariate Cox proportional hazards methods as well as the unadjusted log-rank test. Survival data were visually presented using the Kaplan-Meier survival curve estimator.

RESULTS

Most subjects with IPAF (57.4%; 78/136) had a high-confidence diagnosis of a UIP pattern on CT. Substantially fewer subjects (28.7%; 39/136) had a pattern that was inconsistent with UIP noted on CT. The presence of a UIP pattern on CT was associated with smoking (p < 0.01), male sex (p < 0.01), and older age (p < 0.001). Approximately one-fourth of the subjects had a nonspecific interstitial pneumonitis pattern on CT. Of interest, nearly one-tenth of the subjects had a CT pattern that was most consistent with hypersensitivity pneumonitis rather than the customary CT patterns ascribed to lung disease resulting from connective tissue disease. Most subjects with a possible UIP pattern on CT (83.3%) had UIP diagnosed on the basis of pathologic findings. Focused multivariate analysis showed that honeycombing on CT (hazard ratio, 2.17; 95% CI, 1.05-4.47) and pulmonary artery enlargement on CT (hazard ratio, 2.08; 95% CI, 1.02-4.20) were independent predictors of survival.

CONCLUSION

IPAF most often presents with a UIP pattern on CT and is associated with worse survival when concomitant honeycombing or pulmonary artery enlargement is present.

Densitometric and local histogram based analysis of computed tomography images in patients with idiopathic pulmonary fibrosis

BACKGROUND

Prior studies of clinical prognostication in idiopathic pulmonary fibrosis (IPF) using computed tomography (CT) have often used subjective analyses or have evaluated quantitative measures in isolation. This study examined associations between both densitometric and local histogram based quantitative CT measurements with pulmonary function test (PFT) parameters and mortality. In addition, this study sought to compare risk prediction scores that incorporate quantitative CT measures with previously described systems.

METHODS

Forty six patients with biopsy proven IPF were identified from a registry of patients with interstitial lung disease at Brigham and Women's Hospital in Boston, MA. CT scans for each subject were visually scored using a previously published method. After a semi-automated method was used to segment the lungs from the surrounding tissue, densitometric measurements including the percent high attenuating area, mean lung density, skewness and kurtosis were made for the entirety of each patient's lungs. A separate, automated tool was used to detect and quantify the percent of lung occupied by interstitial lung features. These analyses were used to create clinical and quantitative CT based risk prediction scores, and the performance of these was compared to the performance of clinical and visual analysis based methods.

RESULTS

All of the densitometric measures were correlated with forced vital capacity and diffusing capacity, as were the total amount of interstitial change and the percentage of interstitial change that was honeycombing measured using the local histogram method. Higher percent high attenuating area, higher mean lung density, lower skewness, lower kurtosis and a higher percentage of honeycombing were associated with worse transplant free survival. The quantitative CT based risk prediction scores performed similarly to the clinical and visual analysis based methods.

CONCLUSIONS

Both densitometric and feature based quantitative CT measures correlate with pulmonary function test measures and are associated with transplant free survival. These objective measures may be useful for identifying high risk patients and monitoring disease progression. Further work will be needed to validate these measures and the quantitative imaging based risk prediction scores in other cohorts.

Classification of idiopathic interstitial pneumonias using anti-myxovirus resistance-protein 1 autoantibody

Chronic fibrosing idiopathic interstitial pneumonia (IIP) can be divided into two main types: idiopathic pulmonary fibrosis (IPF), a steroid-resistant and progressive disease with a median survival of 2-3 years, and idiopathic non-specific interstitial pneumonia (INSIP), a steroid-sensitive and non-progressive autoimmune disease. Although the clinical courses of these two diseases differ, they may be difficult to distinguish at diagnosis. We performed a comprehensive analysis of serum autoantibodies from patients definitively diagnosed with IPF, INSIP, autoimmune pulmonary alveolar proteinosis, and sarcoidosis. We identified disease-specific autoantibodies and enriched KEGG pathways unique to each disease, and demonstrated that IPF and INSIP are serologically distinct. Furthermore, we discovered a new INSIP-specific autoantibody, anti-myxovirus resistance-1 (MX1) autoantibody. Patients positive for anti-MX1 autoantibody constituted 17.5% of all cases of chronic fibrosing IIPs. Notably, patients rarely simultaneously carried the anti-MX1 autoantibody and the anti-aminoacyl-transfer RNA synthetase autoantibody, which is common in chronic fibrosing IIPs. Because MX1 is one of the most important interferon-inducible anti-viral genes, we have not only identified a new diagnostic autoantibody of INSIP but also obtained new insight into the pathology of INSIP, which may be associated with viral infection and autoimmunity.

Quantitative assessment of lung stiffness in patients with interstitial lung disease using MR elastography

PURPOSE

To investigate the use of magnetic resonance elastography (MRE) in the quantitative assessment of pulmonary fibrosis by comparing quantitative shear stiffness measurements of lung parenchyma in patients diagnosed with fibrotic interstitial lung disease (ILD) and healthy controls.

MATERIALS AND METHODS

A 1.5T spin-echo, echo planar imaging MRE (SE-EPI MRE) pulse sequence was utilized to assess absolute lung shear stiffness in 15 patients with diagnosed ILD and in 11 healthy controls. Data were collected at residual volume (RV) and total lung capacity (TLC). Spirometry data were obtained immediately prior to scanning. To test for statistical significance between RV and TLC shear stiffness estimates a two-sample t-test was performed. To assess variability within individual subject shear stiffness estimates, the intraclass correlation coefficient (ICC) and Krippendorff's alpha were calculated.

RESULTS

Patients with ILD exhibited an average (±1 standard deviation) shear stiffness of 2.74 (±0.896) kPa at TLC and 1.32 (±0.300) kPa at RV. The corresponding values for healthy individuals were 1.33 (±0.195) kPa and 0.849 (±0.250) kPa, respectively. The difference in shear stiffness between RV and TLC was statistically significant (P < 0.001). At TLC, the ICC and alpha values were 0.909 and 0.887, respectively. At RV, the ICC and alpha values were 0.852 and 0.862, respectively.

CONCLUSION

In subjects with known fibrotic interstitial lung disease, parenchymal shear stiffness is increased when compared to normal controls at both RV and TLC, with TLC demonstrating the most significant difference. MRE-derived parenchymal shear stiffness is a promising new noninvasive imaging-based biomarker of interstitial lung disease.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:365-374.

Imaging of Idiopathic Pulmonary Fibrosis

Idiopathic interstitial pneumonias are a heterogeneous group of diffuse lung diseases characterized by distinct clinicopathologic entities with the usual interstitial pneumonia (UIP) being the most common. The pattern of UIP can be seen in idiopathic pulmonary fibrosis (IPF) as well as in secondary causes, most commonly in connective tissue diseases. IPF is usually progressive and associated with a very poor prognosis, and newer therapies pose a risk of serious complications; therefore, diagnostic certainty is crucial. This article reviews the radiologic findings in UIP with clinical correlation and histopathologic features along with its significance for prognosis and patients monitoring.

Pneumonia

The lung is constantly exposed to airborne infectious agents due to the large surface area of approximately 100 m². Therefore pneumonia is one of the most common lung diseases. Understanding infection requires understanding the routes of infections, the way invading organisms infect epithelial cells, as well as defense mechanisms of the lung tissue acquired during evolution.

 Different variants of infectious and non-infectious pneumonias are discussed; special types of pneumonias such as granulomatous and fibrosing pneumonias are presented under separate sections. Causing organisms and other causes of pneumonias are included, and their mode of action is included as far as understood.

Comparative Proteomic Analysis of Bleomycin-induced Pulmonary Fibrosis Based on Isobaric Tag for Quantitation

BACKGROUND

Pulmonary fibrosis (PF) is a destructive pulmonary disease and the molecular mechanisms underlying PF are unclear. This study investigated differentially expressed proteins associated with the occurrence and development of PF in rat lung tissue with bleomycin-induced PF.

METHODS

Sixteen Sprague-Dawley rats were randomly divided into 2 groups: the PF model group (n = 8) and the control group (n = 8). After successfully establishing the rat PF model induced by bleomycin, the differentially expressed proteins in the 2 groups were identified through isobaric tag for relative and absolute quantitation coupled with liquid chromatography-mass spectrometry and bioinformatics analysis.

RESULTS

A total of 146 differentially expressed proteins were identified; 88 of which displayed increased abundance and 58 were downregulated in the PF rat model group. Most functional proteins were associated with extracellular matrix, inflammation, damage response, vitamin A synthesis and metabolism. Critical proteins related to PF development and progression was identified, such as type V collagen-3, arachidonic acid 12-lipoxygenase, arachidonic acid 15-lipoxygenase and cytochrome P4501A1. Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that these differentially expressed proteins were enriched in extracellular matrix receptor interaction pathway, renin-angiotensin system and metabolic pathway of retinol.

CONCLUSIONS

The proteins expressed in bleomycin-induced PF rat model provide important data for further functional analysis of proteins involved in PF.

Prevalence and characteristics of TERT and TERC mutations in suspected genetic pulmonary fibrosis

Telomerase reverse transcriptase (TERT) or telomerase RNA (TERC) gene mutation is a major monogenic cause of pulmonary fibrosis. Sequencing of TERT/TERC genes is proposed to patients with familial pulmonary fibrosis. Little is known about the possible predictors of this mutation and its impact on prognosis.We retrospectively analysed all the genetic diagnoses made between 2007-2014 in patients with pulmonary fibrosis. We evaluated the prevalence of TERT/TERC disease-associated variant (DAV), factors associated with a DAV, and the impact of the DAV on survival.237 patients with pulmonary fibrosis (153 with familial pulmonary fibrosis, 84 with telomere syndrome features without familial pulmonary fibrosis) were tested for TERT/TERC DAV. DAV was diagnosed in 40 patients (16.8%), including five with non-idiopathic interstitial pneumonia. Prevalence of TERT/TERC DAV did not significantly differ between patients with familial pulmonary fibrosis or with only telomere syndrome features (18.2% versus 16.4%). Young age, red blood cell macrocytosis, and low platelet count were associated with the presence of DAV; the probability of DAV was increased for patients 40-60 years. Transplant-free survival was lower with than without TERT/TERC DAV (4.2 versus 7.2 years; p=0.046).TERT/TERC DAV were associated with specific clinical and biological features and reduced transplant-free survival.

Idiopathic Pulmonary Fibrosis and the Elderly: Diagnosis and Management Considerations

Idiopathic pulmonary fibrosis (IPF) is a severe and progressive fibrosing interstitial lung disease, which ultimately results in respiratory failure and death. The median age at diagnosis is 66 years, and the incidence increases with age, making this a disease that predominantly affects the elderly population. IPF can often be difficult to diagnose, as its symptoms--cough, dyspnoea and fatigue--are non-specific and can often be attributed to co-morbidities such as heart failure and chronic obstructive pulmonary disease. Making an accurate diagnosis of IPF is imperative, as new treatments that appear to slow the progression of IPF have recently become available. Pirfenidone and nintedanib are two such treatments, which have shown efficacy in randomised controlled trials. As with all new treatments, caution must be advocated in the elderly, as these patients often lie outside the narrow clinical trial cohorts that are studied, and the benefits of therapy must be weighed against potential toxicities. Both medications, while relatively safe, have been associated with adverse effects, particularly gastrointestinal symptoms such as nausea, diarrhoea and anorexia. In this review, we highlight measures to improve recognition and accurate diagnosis of IPF, as well as co-morbidities that often affect the diagnosis and disease course. The gold standard for IPF diagnosis is a multidisciplinary meeting whereby clinicians, radiologists and histopathologists reach a consensus after interactive discussion. In many cases, a lung biopsy may not be available because of high risk or patient choice, particularly in the elderly. In these cases, there is debate as to whether a biopsy is required, given the high rates of IPF in patients over the age of 70 years with interstitial changes on computed tomography. We also discuss the management of IPF, drawing particular attention to specific issues affecting the elderly population, especially with regard to polypharmacy and end-of-life care. Through this article, we endeavour to improve awareness of this devastating disease and thus improve recognition of the disease and its outcomes in elderly patients.

Utility of Transbronchial vs Surgical Lung Biopsy in the Diagnosis of Suspected Fibrotic Interstitial Lung Disease

BACKGROUND

Surgical lung biopsy (SLB) is invasive and not possible in all patients with undiagnosed interstitial lung disease (ILD). We hypothesized that transbronchial biopsy (TBB) findings combined with clinical and high-resolution CT (HRCT) data leads to a confident diagnosis congruent to SLB and therefore avoids the need for SLB in some patients.

METHODS

We evaluated 33 patients being investigated for suspected ILD who underwent HRCT, TBB, and SLB. First, clinicians, radiologists, and a pathologist reviewed the clinical information and HRCT and TBB findings. Clinicians were asked to provide a diagnosis and were also asked if SLB was needed for a more confident diagnosis. Subsequently, the clinical, HRCT, and SLB data were reviewed, and the same participants were asked to provide a final diagnosis. Clinician consensus and overall agreement between TBB- and SLB-based diagnoses were calculated.

RESULTS

Four patients had definite usual interstitial pneumonia (UIP) on HRCT and would not be considered for biopsy using current guidelines. Of the 29 patients without a definitive HRCT diagnosis, the clinicians felt confident of the diagnosis (ie, would not recommend SLB) in six cases. In these cases, there was 100% agreement between TBB and SLB diagnoses. UIP was the most common diagnosis (n = 3) and was associated with an HRCT diagnosis of possible UIP/nonspecific interstitial pneumonia-like. Agreement was poor (33%) between TBB and SLB diagnoses when confidence in the TBB diagnosis was low.

CONCLUSIONS

Information from TBB, when combined with clinical and HRCT data, may provide enough information to make a confident and accurate diagnosis in approximately 20% to 30% of patients with ILD.

Diagnostic Approach to Advanced Fibrotic Interstitial Lung Disease: Bringing Together Clinical, Radiologic, and Histologic Clues

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.

Predictors of idiopathic pulmonary fibrosis in absence of radiologic honeycombing: A cross sectional analysis in ILD patients undergoing lung tissue sampling

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) can be diagnosed confidently and non-invasively when clinical and computed tomography (CT) criteria are met. Many do not meet these criteria due to absence of CT honeycombing. We investigated predictors of IPF and combinations allowing accurate diagnosis in individuals without honeycombing.

METHODS

We utilized prospectively collected clinical and CT data from patients enrolled in the Lung Tissue Research Consortium. Included patients had no honeycombing, no connective tissue disease, underwent diagnostic lung biopsy, and had CT pattern consistent with fibrosing ILD (n = 200). Logistic regression identified clinical and CT variables predictive of IPF. The probability of IPF was assessed at various cut-points of important clinical and CT variables.

RESULTS

A multivariable model adjusted for age and gender found increasingly extensive reticular densities (OR 2.93, CI 95% 1.55-5.56, p = 0.001) predicted IPF, while increasing ground glass densities predicted a diagnosis other than IPF (OR 0.55, CI 95% 0.34-0.89, p = 0.02). The model-based probability of IPF was 80% or greater in patients with age at least 60 years and extent of reticular density one-third or more of total lung volume; for patients meeting or exceeding these clinical thresholds the specificity for IPF is 96% (CI 95% 91-100%) with 21 of 134 (16%) biopsies avoided.

CONCLUSIONS

In patients with suspected fibrotic ILD and absence of CT honeycombing, extent of reticular and ground glass densities predict a diagnosis of IPF. The probability of IPF exceeds 80% in subjects over age 60 years with one-third of total lung having reticular densities.

Heterogeneity of incidence and outcome of acute exacerbation in idiopathic interstitial pneumonia

BACKGROUND AND OBJECTIVE

Acute exacerbations (AEs) of idiopathic pulmonary fibrosis (IPF) and other idiopathic interstitial pneumonia (IIP) have a poor prognosis. This study aims to clarify the incidence and prognosis of AE in IPF and the other IIP.

METHODS

A total of 229 patients were enrolled, of whom 92 had IPF and 137 had 'IIP other than IPF' based on the American Thoracic Society/European Respiratory Society/Japanese Respiratory Society/Latin American Thoracic Association (ATS/ERS/JRS/ALAT) 2011 IPF Guidelines. IIP other than IPF included 11 patients with a surgical lung biopsy (SLB) and the remainder without such a biopsy. IIP other than IPF was further classified into IIP with a 'possible usual interstitial pneumonia (UIP)' pattern on HRCT (n = 75) and IIP with 'inconsistent with UIP' pattern (n = 62) based on published guidelines. Predictors of AE and the prognosis after AE were examined in these groups.

RESULTS

The 1-year incidence of AE in IPF, IIP with possible UIP HRCT patterns and IIP with inconsistent with UIP HRCT patterns was 16.5%, 8.9% and 4.0%, respectively. AE occurred significantly more frequently in IPF than in IIP with possible UIP and inconsistent with UIP HRCT patterns after adjustment for BMI, modified Medical Research Council score and %forced vital capacity. Prognosis of AE-IIP with possible UIP HRCT pattern was significantly worse than that of AE-IPF.

CONCLUSION

Although AE occurred significantly less frequently in IIP with possible UIP and inconsistent with UIP HRCT patterns than in IPF, the prognosis of AE-IIP with possible UIP HRCT patterns might be worse than that of AE-IPF.

Surgical Lung Biopsy for Interstitial Lung Diseases

This review addresses common questions regarding the role of surgical lung biopsy (SLB) in the diagnosis and treatment of interstitial lung disease (ILD). We specifically address when a SLB can be diagnostic as well as when it may be avoided; for example, when the combination of the clinical context and the imaging pattern seen on high-resolution CT (HRCT) chest scans can provide a confident diagnosis. Existing studies on the diagnostic utility as well as the complications associated with SLB are reviewed; also reviewed are the performance characteristics and reliability of HRCT scans of the chest in predicting the underlying histopathologic findings of the lung. The review is formatted in the form of answers to questions that clinicians regularly ask when considering an SLB in a patient with ILD.

Eosinophil alveolitis in two patients with idiopathic pulmonary fibrosis

Bronchoalveolar lavage fluid (BALF) in patients with idiopathic pulmonary fibrosis (IPF) is typically characterized by a neutrophil inflammatory pattern and to a lesser extent (<25%) a mild eosinophil alveolitis. We here present two patients with a definite usual interstitial pneumonia (UIP) pattern on high-resolution computed tomography of the thorax (HRCT) which demonstrated unusually high eosinophil counts in the BALF (40% and 51%). Based on HRCT, lack of response to steroids and the disease course they were both diagnosed as IPF after a multidisciplinary team discussion. This report discusses the diagnostic and etiological considerations of a coexisting UIP pattern and an eosinophil alveolitis. We conclude that these cases illustrate that high level BALF eosinophilia (40–50%) may occur among patients with IPF.

The Value of a Multidisciplinary Approach to the Diagnosis of Usual Interstitial Pneumonitis and Idiopathic Pulmonary Fibrosis: Radiology, Pathology, and Clinical Correlation

OBJECTIVE

Multidisciplinary discussion is essential in establishing the diagnosis of idiopathic pulmonary fibrosis (IPF) and in determining prognosis.

CONCLUSION

The CT and histopathologic correlate for IPF is usual interstitial pneumonitis (UIP). If a high-confidence diagnosis of UIP is made on CT, IPF is almost always the diagnosis, obviating lung biopsy. If a confident diagnosis of UIP cannot be made on CT, further assessment with lung biopsy and multidisciplinary discussion are often necessary to achieve a confident final diagnosis.

Lung diffusing capacity for nitric oxide as a marker of fibrotic changes in idiopathic interstitial pneumonias

Lung diffusing capacity for carbon monoxide (DLCO) is decreased in both usual interstitial pneumonia-idiopathic pulmonary fibrosis (UIP-IPF) and nonspecific interstitial pneumonia (NSIP), but is moderately related to computed tomography (CT)-determined fibrotic changes. This may be due to the relative insensitivity of DLCO to changes in alveolar membrane diffusive conductance (DMCO). The purpose of this study was to determine whether measurement of lung diffusing capacity for nitric oxide (DLNO) better reflects fibrotic changes than DLCO. DLNO-DLCO were measured simultaneously in 30 patients with UIP-IPF and 30 with NSIP. Eighty-one matched healthy subjects served as a control group. The amount of pulmonary fibrosis was estimated by CT volumetric analysis of visually bounded areas showing reticular opacities and honeycombing. DMCO and pulmonary capillary volume (VC) were calculated. DLNO was below the lower limit of normal in all patients irrespective of extent and nature of disease, whereas DLCO was within the normal range in a nonnegligible number of patients. Both DLNO and DLCO were significantly correlated with visual assessment of fibrosis but DLNO more closely than DLCO. DMCO was also below the lower limit of normal in all UIP-IPF and NSIP patients and significantly correlated with fibrosis extent in both diseases, whereas VC was weakly correlated with fibrosis in UIP-IPF and uncorrelated in NSIP, with normal values in half of patients. In conclusion, measurement of DLNO may provide a more sensitive evaluation of fibrotic changes than DLCO in either UIP-IPF or NSIP, because it better reflects DMCO.

Comparisons of Prognosis between Surgically and Clinically Diagnosed Idiopathic Pulmonary Fibrosis Using Gap Model: A Korean National Cohort Study

Although a multidisciplinary approach has become an important criterion for an idiopathic pulmonary fibrosis (IPF) diagnosis, lung biopsies remain crucial. However, the prognosis of patients with surgically diagnosed IPF (sIPF) is uncertain. We aimed to investigate the prognosis of patients with clinically diagnosed IPF (cIPF) and sIPF. In this retrospective observational study, the Korean Interstitial Lung Disease Study Group conducted a national survey to evaluate the clinical, physiological, radiological, and survival characteristics of patients with IPF from January 1, 2003 to December 31, 2007. Patients were recruited from 54 universities and teaching hospitals across the Republic of Korea. IPF diagnoses were established according to the 2002 American Thoracic Society (ATS)/European Respiratory Society criteria (ERS) guideline. A total of 1685 patients with IPF (1027 cIPF and 658 sIPF) were enrolled. Patients with sIPF were significantly younger, predominantly female, and nonsmokers (all P < 0.001). sIPF group had significantly better initial pulmonary function. The proportion of computed tomography-based honeycomb findings of patients with cIPF was higher than in those with sIPF (P < 0.001). A Kaplan-Meier analysis showed that the sIPF group had a better prognosis (P = 0.001). A survival analysis showed that age, pulmonary function parameters, pulmonary oxygen tension, honeycombing change, and combined lung cancer had a significant influence on patient prognosis. However, there was no significant difference in prognosis between the cIPF and sIPF groups after adjusting for GAP (gender, age, physiology) stage. The patients with sIPF had better clinical features than those with cIPF. However, after adjusting for GAP stage, the sIPF group showed similar prognoses as the cIPF group. This study showed that after adjusting for GAP stage, the prognosis of patients with IPF is the same regardless of the diagnostic method used.

Radiologic–pathologic discordance in biopsy-proven usual interstitial pneumonia

The aim of this study was to compare the clinical, radiological and histological findings in a large population of subjects enrolled during a multicentre study of idiopathic pulmonary fibrosis, with a focus on discordance between imaging and histologic diagnoses of usual interstitial pneumonia (UIP).

Two independent radiologists retrospectively reviewed 241 subjects who underwent high-resolution computed tomography (HRCT) and surgical lung biopsies. HRCT findings were classified as UIP, possible UIP and inconsistent with UIP. Histological findings were classified as definite, probable, possible and not UIP.

Of the 241 cases, 102 (42.3%) had HRCT findings of UIP, 64 (26.6%) had possible UIP and 75 (31.1%) were inconsistent with UIP. Among those with UIP on HRCT, 99 (97.1%) had histologically definite or probable UIP (concordant group), and 71 (94.7%) of those with “inconsistent” HRCT features had histologically definite or probable UIP (discordant group). Discordant subjects were slightly younger and less likely to be smokers than concordant subjects, but no survival differences were identified.

In this population of patients enrolled with a diagnosis of idiopathic pulmonary fibrosis, 94.7% of those with HRCT findings “inconsistent with UIP” demonstrated histological UIP. This suggests that the term “inconsistent with UIP” is misleading.

CT Imaging Phenotypes of Pulmonary Fibrosis in the MUC5B Promoter Site Polymorphism

BACKGROUND

To determine the effect of the MUC5B promoter polymorphism (rs35705950) on the CT imaging appearance of pulmonary fibrosis.

METHODS

High-resolution CT scans of 1,764 subjects were scored as part of a, genomewide association study with institutional review board approval; 1,491 of these had pulmonary fibrosis on CT scans and were included in the study. Two thoracic radiologists independently scored CT scans systematically. Discrepancies were resolved by a third thoracic radiologist. All patients were genotyped specifically for the rs35705950 single-nucleotide polymorphism (SNP). Two-tailed Fisher exact or χ(2) tests and Student t tests or Mann-Whitney U tests were used to compare proportions and means, respectively.

RESULTS

The major and minor alleles at the rs35705950 SNP are guanine (G) and thymine (T), respectively: 514 were homozygous for the major allele (G group), and 977 were heterozygous or homozygous for the minor allele (T group). The G group had a higher proportion than the T group with ground-glass opacity (62.1% vs 54.2%; P = .04). There was no significant difference between the G and T groups regarding presence of honeycombing. The T group showed a significantly higher subpleural axial distribution of fibrosis than did the G group (62.3% vs 42.2%; P < .0001). The T group showed a lower proportion of diagnoses inconsistent with usual interstitial pneumonitis (UIP; 20.3% compared with 30.5% for the G group) and a greater proportion of confident (probable UIP and UIP) UIP diagnoses (43.8% compared with 32.6% for the G group).

CONCLUSIONS

The MUC5B promoter polymorphism identifies a pattern of fibrosis that is different from other causes of fibrosis and may respond differently to potential therapies.

Rheumatoid arthritis-associated lung disease

Comprehensive, up-to-date review of RA-associated lung diseases including pathogenesis and managementhttp://ow.ly/FBaNZ

Plakoglobin expression in fibroblasts and its role in idiopathic pulmonary fibrosis

Background

Idiopathic pulmonary fibrosis (IPF) is an interstitial fibrotic lung disease of unknown origin and without effective therapy characterized by deposition of extracellular matrix by activated fibroblasts in the lung. Fibroblast activation in IPF is associated with Wnt/β-catenin signaling, but little is known about the role of the β-catenin-homologous desmosomal protein, plakoglobin (PG), in IPF. The objective of this study was to assess the functional role of PG in human lung fibroblasts in IPF.

Methods

Human lung fibroblasts from normal or IPF patients were transfected with siRNA targeting PG and used to assess cellular adhesion to a fibronectin substrate, apoptosis and proliferation. Statistical analysis was performed using Student’s t-test with Mann–Whitney post-hoc analyses and results were considered significant when p < 0.05.

Results

We found that IPF lung fibroblasts expressed less PG protein than control fibroblasts, but that characteristic fibroblast phenotypes (adhesion, proliferation, and apoptosis) were not controlled by PG expression. Consistent with this, normal fibroblasts in which PG was silenced displayed no change in functional phenotype.

Conclusions

We conclude that diminished PG levels in IPF lung fibroblasts do not directly affect certain phenotypic behaviors. Further study is needed to identify the functional consequences of decreased PG in these cells.

American Thoracic Society-European Respiratory Society Classification of the Idiopathic Interstitial Pneumonias: Advances in Knowledge since 2002

In the updated American Thoracic Society-European Respiratory Society classification of the idiopathic interstitial pneumonias (IIPs), the major entities have been preserved and grouped into (a) "chronic fibrosing IIPs" (idiopathic pulmonary fibrosis and idiopathic nonspecific interstitial pneumonia), (b) "smoking-related IIPs" (respiratory bronchiolitis-associated interstitial lung disease and desquamative interstitial pneumonia), (c) "acute or subacute IIPs" (cryptogenic organizing pneumonia and acute interstitial pneumonia), and (d) "rare IIPs" (lymphoid interstitial pneumonia and idiopathic pleuroparenchymal fibroelastosis). Furthermore, it has been acknowledged that a final diagnosis is not always achievable, and the category "unclassifiable IIP" has been proposed. The diagnostic interpretation of the IIPs is often challenging because other diseases with a known etiology (most notably, connective tissue disease and hypersensitivity pneumonitis) may show similar morphologic patterns. Indeed, more emphasis has been given to the integration of clinical, computed tomographic (CT), and pathologic findings for multidisciplinary diagnosis. Typical CT-based morphologic patterns are associated with the IIPs, and radiologists play an important role in diagnosis and characterization. Optimal CT quality and a systematic approach are both pivotal for evaluation of IIP. Interobserver variation for the various patterns encountered in the IIPs is an issue. It is important for radiologists to understand the longitudinal behavior of IIPs at serial CT examinations, especially for providing a framework for cases that are unclassifiable or in which a histologic diagnosis cannot be obtained.

Clinical features of rheumatoid arthritis-associated interstitial lung disease

Interstitial lung disease (ILD) is the most common extra-articular manifestations of rheumatoid arthritis (RA) in the lung. This study aimed to identify clinical features of RA-associated ILD (RA-ILD). Patients with RA were retrospectively enrolled and sub-classified as RA-ILD or RA without ILD based on high-resolution computed tomography imaging. Pulmonary function testing parameters and levels of RA-related biomarkers, tumour markers, and acute-phase proteins were compared between the two groups. Logistic regression model was used to assess the strength of association between RA-ILD and clinical features of interest. Receiver operating characteristic analysis was performed to assess potential predictive value of clinical features for detecting RA-ILD. Comparison analysis indicated that the percentage of predicted value of total lung capacity, inspiratory capacity, and diffusion capacity of the lung for carbon monoxide (DLCO) were reduced in patients with RA-ILD. Tumour markers CA15–3 and CA125 were increased in patients with RA-ILD. Logistic regression analysis revealed that decreased DLCO was related to the increased likelihood of RA-ILD (OR = 0.94, 95%CI = [0.91, 0.98]). The cut-off point at 52.95 percent of predicted value could sensitively discriminate RA patients with or without ILD. Our study suggested that DLCO value could be a useful tool for detecting ILD in patients with RA.

Management of Idiopathic Pulmonary Fibrosis in the Elderly Patient: Addressing Key Questions

Idiopathic pulmonary fibrosis (IPF) is strongly associated with advanced age. Making an accurate diagnosis of IPF is critical, as it remains only one of many potential diagnoses for an elderly patient with newly recognized interstitial lung disease. Optimal management of IPF, especially in older-aged patients, hinges on such factors as balancing the application of standard-of-care measures with the patient's overall health status (robustness vs frailty) and considering the patient's wishes, desires, and expectations. IPF is known to be associated with certain comorbidities that tend to be more prevalent in the elderly population. Until recently, options for the pharmacologic management of IPF were limited and included therapies such as immunosuppressive agents, which may pose substantial risk to the elderly patient. However, the antifibrotic agents pirfenidone and nintedanib have now become commercially available in the United States for the treatment of IPF. The monitoring and treatment of patients with IPF, especially elderly patients with comorbid medical conditions, require consideration of adverse side effects, the avoidance of potential drug-drug interactions, treatment of comorbidities, and the timely implementation of supportive and palliative measures. Individualized counseling to guide decision-making and enhance quality of life is also integral to optimal management of the elderly patient with IPF.

Management of Rheumatoid Arthritis Patients with Interstitial Lung Disease: Safety of Biological Antirheumatic Drugs and Assessment of Pulmonary Fibrosis

Interstitial lung disease (ILD) is one of the major causes of morbidity and mortality of patients with rheumatoid arthritis (RA). Accompanying the increased number of reports on the development or exacerbation of ILD in RA patients following therapy with biological disease-modifying antirheumatic drugs (DMARDs), RA-associated ILD (RA-ILD) has aroused renewed interest. Although such cases have been reported mainly in association with the use of tumor necrosis factor inhibitors, the use of other biological DMARDs has also become a matter of concern. Nevertheless, it is difficult to establish a causative relationship between the use of biological DMARDs and either the development or exacerbation of ILD. Such pulmonary complications may occur in the natural course of RA regardless of the use of biological DMARDs. Since rheumatologists currently aim to achieve remission in RA patients, the administration of biological DMARDs is increasing, even for those with RA-ILD. However, there are no reliable, evidence-based guidelines for deciding whether biological DMARDs can be safely introduced and continued in RA-ILD patients. A standardized staging system for pulmonary conditions of RA-ILD patients is needed when making therapeutic decisions at baseline and monitoring during biological DMARD therapy. Based on the available information regarding the safety of biological DMARDs and the predictive factors for a worse prognosis, this review discusses candidate parameters for risk evaluation of ILD in RA patients who are scheduled to receive biological antirheumatic therapy.

Diagnosis of biopsy verified usual interstitial pneumonia by computed tomography

OBJECTIVE

To identify the combination of clinical data and high resolution computed tomography (HRCT) features that best identified biopsy verified usual interstitial pneumonia (UIP).

METHODS

The study included 91 patients with a tentative diagnosis of interstitial lung disease. All underwent clinical investigation, surgical lung biopsy and HRCT. Two independent readers assessed the HRCT images for the extent and pattern of abnormality. On the basis of the biopsy result the patients were categorized in three groups: 1) Usual interstitial pneumonia, 2) Other idiopathic interstitial pneumonias (IIPs) and hypersensitivity pneumonitis and 3) Other interstitial lung diseases. The diagnostic value of HRCT was investigated using likelihood ratio to estimate the post-test probability of UIP.

RESULTS

We found that UIP was associated with significantly higher scores for reticular pattern and for bronchiectasis than the remaining patients (p < 0.001). Moreover, these scores showed a steeper cranial-caudal increase in patients with histologically verified UIP than in the remaining patients (p < 0.001). UIP was associated with lower scores for ground glass opacities (p < 0.001). Using Bayes theorem and likelihood ratio estimation we found that UIP could be diagnosed with 90% certainty in patients 60 years or older and restrictive pattern in spirometry provided that HRCT demonstrated at least 15% reticular pattern and no ground glass opacities.

CONCLUSION

In older patients with a restrictive spirometry in whom HRCT demonstrates a reticular pattern without ground glass opacities surgical lung biopsy is not warranted for the diagnosis of UIP.

Usual interstitial pneumonia end-stage features from explants with radiologic and pathological correlations

Idiopathic pulmonary fibrosis (IPF) is the most frequent and severe idiopathic interstitial pneumonia, with typical high-resolution computed tomography (HRCT) features and histologic pattern of usual interstitial pneumonia (UIP); its main differential diagnosis is fibrotic nonspecific interstitial pneumonia (F-NSIP). Usual interstitial pneumonia was mainly described from lung biopsies, and little is known on explants. Twenty-two UIP/IPF explants were analyzed histologically and compared with previous open lung biopsies (OLBs; n = 11) and HRCT (n = 19), when available. Temporospatial heterogeneity and subpleural and paraseptal fibrosis were similarly found in UIP/IPF explants and OLB (91%-95%). Fibroblastic foci were found in 82% of OLBs and 100% of explants, with a higher mean score in explants (P = .023). Honeycombing was present in 64% of OLBs and 95% of explants, with a higher mean score in explants (P = .005). Almost 60% of UIP/IPF explants showed NSIP areas and 41% peribronchiolar fibrosis; inflammation, bronchiolar metaplasia, and vascular changes were more frequent in UIP/IPF explants; and Desquamative Interstitial Pneumonia (DIP)-like areas were not common (18%-27%). Numerous large airspace enlargements with fibrosis were frequent in UIP/IPF explants (59%). On HRCT, honeycombing was observed in 95% of the cases and ground-glass opacities in 53%, correlating with NSIP areas or acute exacerbation at histology. Six patients had combined IPF and emphysema. Lesions were more severe in UIP/IPF explants, reflecting the worsening of the disease. Usual interstitial pneumonia/IPF explants more frequently presented with confounding lesions such as NSIP areas, peribronchiolar fibrosis, and airspace enlargements with fibrosis sometimes associated with emphysema.

Diagnosis of idiopathic pulmonary fibrosis: Current issues

Idiopathic pulmonary fibrosis (IPF) accounts for the majority of lung diseases classified as idiopathic interstitial pneumonia (IIP). It is considered to be lethal because prognosis is very poor and far worse than other types of IIP. An early and accurate diagnosis of IPF is critical. The diagnostic process is complex and requires a multidisciplinary approach involving a pulmonologist, radiologist and pathologist.

CT scan findings of probable usual interstitial pneumonitis have a high predictive value for histologic usual interstitial pneumonitis

BACKGROUND

The current usual interstitial pneumonitis (UIP)/idiopathic pulmonary fibrosis CT scan classification system excludes probable UIP as a diagnostic category. We sought to determine the predictive effect of probable UIP on CT scan on histology and the effect of the promoter polymorphism in MUC5B (rs35705950) on histologic and CT scan UIP diagnosis.

METHODS

The cohort included 201 subjects with pulmonary fibrosis who had lung tissue samples obtained within 1 year of chest CT scan. UIP diagnosis on CT scan was categorized as inconsistent with, indeterminate, probable, or definite UIP by two to three pulmonary radiologists. Tissue slides were scored by two expert pulmonary pathologists. All subjects with available DNA (N = 200) were genotyped for rs35705950.

RESULTS

The proportion of CT scan diagnoses were as follows: inconsistent with (69 of 201, 34.3%), indeterminate (72 of 201, 35.8%), probable (34 of 201, 16.9%), and definite (26 of 201, 12.9%) UIP. Subjects with probable UIP on CT scan were more likely to have histologic probable/definite UIP than subjects with indeterminate UIP on CT scan (82.4% [28 of 34] vs 54.2% [39 of 72]; P = .01). CT scan and microscopic honeycombing were not associated with each other (P = .76). The minor (T) allele of the MUC5B polymorphism was associated with concordant CT scan and histologic UIP diagnosis (P = .03).

CONCLUSIONS

Probable UIP on CT scan is associated with a higher rate of histologic UIP than indeterminate UIP on CT scan suggesting that they are distinct groups and should not be combined into a single CT scan category as currently recommended by guidelines. CT scan and microscopic honeycombing may be dissimilar entities. The T allele at rs35705950 predicts a UIP diagnosis by both chest CT scan and histology.

HRCT of fibrosing lung disease

The use of high-resolution computed tomography (HRCT) has brought increased diagnostic discrimination to the evaluation of lung disease, particularly fibrosing lung diseases. Once the presence of a predominantly fibrosing lung disease has been established on evaluation of a HRCT, a stepwise approach is proposed that can refine the potential HRCT diagnoses from a list of over 100 different interstitial lung diseases to one of only five fibrosing lung diseases. Within the category of the fibrosing lung diseases, the recognition of idiopathic pulmonary fibrosis (IPF) is key. IPF is the most prevalent idiopathic interstitial pneumonia and has a mortality greater than any of the other diffuse lung diseases. Several diagnostic dilemmas are explored including challenges with the recent IPF diagnosis and management guidelines (2011), as well as with the 'difficult to characterize' fibrosing diseases such as smoking-related lung fibrosis, unclassifiable disease and acute exacerbations of fibrosing lung disease.

The diagnosis and treatment of idiopathic pulmonary fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is the most common idiopathic interstitial disease of the lung and has the worst prognosis of all such diseases, with a median survival time of three to four years. Its prevalence is 2-29 per 100,000 persons and its incidence approximately 10 per 100,000 persons per year, with an upward trend.

METHOD

Selective literature search in the EMBASE and PubMed databases for pertinent publications from 1996 to 2012, with special attention to randomized controlled trials.

RESULTS

IPF manifests itself clinically with exertional dyspnea, dry cough, and inspiratory crepitations (sclerosiphonia). The diagnosis is confirmed by the demonstration of a usual interstitial pneumonia (UIP) pattern in a high-resolution thin-slice CT (HRCT) of the lungs, or else histologically by lung biopsy, along with the exclusion of other causes such as asbestosis or connective tissue disease. In 15 randomized controlled therapeutic trials carried out since 2004, most of the drugs that were tested, including immune suppressants, were found to be ineffective against IPF or even harmful. Only pirfenidone lessens the annual reduction of pulmonary volume (FVC, forced expiratory vital capacity) and of the distance walked in 6 minutes by about 30%, with corresponding improvement of progression-free survival, but without any significant lessening of overall mortality (placebo, 10%; pirfenidone, 8%). Pirfenidone also commonly causes gastrointestinal and cutaneous side effects. The efficacy of N-acetyldysteine and nintedanib has not yet been definitively demonstrated. Lung transplantation is the only current treatment that enables long-term survival.

CONCLUSION

IPF has a worse prognosis than many types of cancer. Drugs can delay the progression of the disease but probably cannot bring it to a permanent standstill.

Cardiovascular involvement in connective tissue disease: the role of interstitial lung disease

Objective

The aim of this study was to assess cardiovascular involvement in patients with connective tissue disease (CTD), and determine whether interstitial lung disease (ILD) in these patients is associated with elevated cardiovascular risk.

Methods

This study evaluated a retrospective cohort of 436 CTD patients admitted to a large teaching hospital in Zhejiang province, China, along with an additional 436 participants of an annual community health screening conducted in the physical examination center who served as age- and gender-matched controls. Demographic, clinical, serologic and imaging characteristics, as well as medications used by each participant were recorded. Cardiovascular involvement was defined by uniform criteria. Correlations between clinical/serologic factors and cardiovascular involvement were determined by univariate and multivariate analyses.

Results

CTD patients had a significantly higher cardiovascular involvement rate than controls (64.7% vs 23.4%), with higher rates of diabetes, hypertension, and hyperlipidemia, elevated systolic and diastolic pressures, C-reactive protein, total cholesterol, and low-density lipoprotein cholesterol, and lower albumin and high-density lipoprotein cholesterol (all p < 0.05). Furthermore, CTP patients with cardiovascular involvement were significantly older, had higher systolic and diastolic pressures, C-reactive protein, glucose, and uric acid, higher rates of diabetes, hypertension, and use of moderate- to high-dose glucocorticoids, and longer disease duration compared to patients without involvement (all p < 0.05). Moreover, CTD in patients with cardiovascular involvement was more likely to be complicated by ILD (p < 0.01), which manifested as a higher alveolar inflammation score (p < 0.05). In the multivariate analysis, cardiovascular involvement in CTD patients was associated with age, systolic pressure, body mass index, uric acid, disease duration > 2 years, use of moderate- to high-dose glucocorticoids, and ILD with a high alveolar inflammation score.

Conclusion

Cardiovascular involvement is increased in CTD patients, and is associated with ILD with a higher alveolar inflammation score. Thus, early-stage echocardiography and CT scans should be used to detect potential cardiovascular complications in these patients.