PATHOLOGIC MANIFESTATIONS OF BRONCHIOLITIS, CONSTRICTIVE BRONCHIOLITIS, CRYPTOGENIC ORGANIZING PNEUMONIA, AND DIFFUSE PANBRONCHIOLITIS

Role of transforming growth factor-β in airway remodelling in bronchiolitis obliterans

Airway remodelling is the main pathological mechanism of bronchiolitis obliterans (BO). Several studies have found that transforming growth factor-β (TGF-β) expression is increased in BO during airway remodelling, where it plays an important role in various biological processes by binding to its receptor complex to activate multiple signalling proteins and pathways. This review examines the role of TGF-β in airway remodelling in BO and its potential as a therapeutic target, highlighting the mechanisms of TGF-β activation and signalling, cellular targets of TGF-β actions, and research progress in TGF-β signalling and TGF-β-mediated processes.

Environmental and occupational bronchiolitis obliterans: new reality

Patients diagnosed with environmental/occupational bronchiolitis obliterans (BO) over the last 2 decades often present with an indolent evolution of respiratory symptoms without a history of high-level, acute exposure to airborne toxins. Exertional dyspnea is the most common symptom and standard clinical and radiographic evaluation can be non-diagnostic. Lung biopsies often reveal pathological abnormalities affecting all distal lung compartments. These modern cases of BO typically exhibit the constrictive bronchiolitis phenotype of small airway remodeling, along with lymphocytic inflammation. In addition, hypertensive-type remodeling of intrapulmonary vasculature, diffuse fibroelastosis of alveolar tissue, and fibrous thickening of visceral pleura are frequently present. The diagnosis of environmental/occupational BO should be considered in patients who present with subacute onset of exertional dyspnea and a history compatible with prolonged or recurrent exposure to environmental toxins. Important areas for future studies include development of less invasive diagnostic approaches and testing of novel agents for disease prevention and treatment.

Severe cryptogenic bronchiolitis: Case report

Bronchiolitis obliterans (BO) is a progressive fibrotic process that predominantly affects the small airways and is identified as constrictive bronchiolitis by pathologists. It is commonly associated with allogeneic hematopoietic stem cell transplant (HSCT), lung transplant, exposure to inhaled toxins, post-infectious processes, autoimmune diseases, and sometimes, no known cause. In the latter case, it is referred to as cryptogenic bronchiolitis obliterans. A 52-year-old Hispanic man with a medical history of hypertension, diabetes mellitus, and coronary artery disease was referred to the pulmonary department due to experiencing dyspnea on exertion, intermittent dry cough, and progressive limitation of activities of daily living. Spirometry revealed severe obstructive changes, and chest high-resolution computed tomography showed ground-glass opacities with nodular infiltrates in the upper lobes, leading to a presumptive diagnosis of hypersensitivity pneumonitis. The patient underwent a lung surgical biopsy of the right upper and lower lobes, which revealed extensive constrictive bronchiolitis. Due to the patient's worsening general condition, bilateral lung transplantation succeeded without any further complications. Following the transplantation, the patient showed good recovery and functional improvement. Bronchiolitis obliterans, or constrictive bronchiolitis, has a variable natural history. It is associated with a higher risk of mortality in allogenic HSCT. When BO is secondary to inhalation of toxic gases, it is usually nonprogressive and limited to toxin exposure. Autoimmune diseases or cryptogenic bronchiolitis are rare and have a heterogeneous clinical course. To make a proper diagnosis, clinical history, radiologic and histologic findings must be considered.

Update in postinfectious bronchiolitis obliterans

Postinfectious bronchiolitis obliterans (PiBO) is a rare and severe form of chronic obstructive lung disease caused by an infectious injury to the lower respiratory tract. The most commonly recognized inciting stimuli leading to PiBO are airway pathogens, such as adenovirus and Mycoplasma. PiBO is characterized by persistent and nonreversible airway obstruction, with functional and radiological evidence of small airway involvement. The literature has limited information on the aetiology, clinical profile, treatment, and outcome of PiBO.

Update on cryptogenic organizing pneumonia

Cryptogenic organizing pneumonia (COP) is a form of idiopathic interstitial pneumonia that results from the pulmonary reaction to various unidentified injuries. Secondary organizing pneumonia is diagnosed when the triggering factor has been identified; it is mainly caused by infections, toxic substance exposure, drugs, connective tissue diseases, malignancies, autoimmune diseases, bone marrow, or organ transplantation, and radiotherapy. There has been an increase in the number of reports of drug-induced organizing pneumonia (OP). New biological therapies, interferon, monoclonal antibodies, anti-interleukin antibodies, and PD1/PDL-1 inhibitors may induce this specific pulmonary reaction. The classical form of COP is usually subacute and does not manifest as severe disease. Patients maintain sufficient respiratory function, and treatment with steroids is usually effective. Several specific forms of OP (e.g., the cicatricial variant or acute fibrinous type) have distinct clinical and histological features, require higher doses of immunosuppressive drugs, and have a worse prognosis. In the era of administering steroid-sparing therapies for the treatment of interstitial lung diseases, connective tissue dases, and other conditions, it is important to emphasize this type of therapy for patients with COP.

A breath of not so fresh air…

Despite being widely used as a recreational drug, "poppers" lack a legal framework for their delivery. Their composition may vary largely. This report describes a case of severe bronchiolitis following amyl nitrite mixture inhalation. https://bit.ly/3p3S7LM.

Childhood Interstitial Lung Disease: Imaging Guidelines and Recommendations

Childhood interstitial lung disease (ChILD) is an umbrella term encompassing a diverse group of diffuse lung diseases affecting infants and children. Although the timely and accurate diagnosis of ChILD is often challenging, it is optimally achieved through the multidisciplinary integration of imaging findings with clinical data, genetics, and potentially lung biopsy. This article reviews the definition and classification of ChILD; the role of imaging, pathology, and genetics in ChILD diagnosis; treatment options; and future goals. In addition, a practical approach to ChILD imaging based on the latest available research and the characteristic imaging appearance of ChILD entities are presented.

Cryptogenic organising pneumonia: current understanding of an enigmatic lung disease

Organising pneumonia (OP) is currently recognised as a nonspecific lung injury response that is associated with a variety of imaging patterns obtained with high-resolution computed tomography (HRCT) of the chest and is characterised histopathologically by the presence of inflammatory cells and a connective tissue matrix within distal airspaces of the lungs. OP is associated with many conditions that include connective tissue disorders, various infections, drug reactions, hypersensitivity pneumonitis and aspiration. When OP cannot be linked to an associated condition and appears to be idiopathic, it is termed cryptogenic organising pneumonia.

Complications of Lung Transplantation: Update on Imaging Manifestations and Management

As lung transplantation has become the most effective definitive treatment option for end-stage chronic respiratory diseases, yearly rates of this surgery have been steadily increasing. Despite improvement in surgical techniques and medical management of transplant recipients, complications from lung transplantation are a major cause of morbidity and mortality. Some of these complications can be classified on the basis of the time they typically occur after lung transplantation, while others may occur at any time. Imaging studies, in conjunction with clinical and laboratory evaluation, are key components in diagnosing and monitoring these conditions. Therefore, radiologists play a critical role in recognizing and communicating findings suggestive of lung transplantation complications. A description of imaging features of the most common lung transplantation complications, including surgical, medical, immunologic, and infectious complications, as well as an update on their management, will be reviewed here. Keywords: Pulmonary, Thorax, Surgery, Transplantation Supplemental material is available for this article. © RSNA, 2021.

Overview and Challenges of Bronchiolar Disorders

Bronchiolar abnormalities are common and can occur in conditions that affect either the large airways or the more distal parenchyma. In this review, we focus on the diagnosis and management of primary bronchiolar disorders, or conditions in which bronchiolitis is the predominant pathologic process, including constrictive bronchiolitis, follicular bronchiolitis, acute bronchiolitis, respiratory bronchiolitis, and diffuse panbronchiolitis. Due to the nature of abnormalities in the small airway, clinical and physiological changes in bronchiolitis can be subtle, making diagnosis challenging. Primary bronchiolar disorders frequently present with progressive dyspnea and cough that can be out of proportion to imaging and physiologic studies. Pulmonary function tests may be normal, impaired in an obstructive, restrictive, or mixed pattern, or have an isolated decrease in diffusion capacity. High-resolution computed tomography scan is an important diagnostic tool that may demonstrate one or more of the following three patterns: 1) solid centrilobular nodules, often with linear branching opacities (i.e., "tree-in-bud" pattern); 2) ill-defined ground glass centrilobular nodules; and 3) mosaic attenuation on inspiratory images that is accentuated on expiratory images, consistent with geographic air trapping. Bronchiolitis is often missed on standard transbronchial lung biopsies, as the areas of small airway involvement can be patchy. Fortunately, many patients can be diagnosed with a combination of clinical suspicion, inspiratory and expiratory high-resolution computed tomography scans, and pulmonary function testing. Joint consultation of clinicians with both radiologists and pathologists (in cases where histopathology is pursued) is critical to appropriately assess the clinical-radiographic-pathologic context in each individual patient.

Risk factors for the development of bronchiolitis obliterans in children with severe adenovirus pneumonia: A retrospective study with dose-response analysis

To investigate and analyze the relevant risk factors for bronchiolitis obliterans (BO) in children with severe adenovirus pneumonia, a retrospective study of children with severe adenovirus pneumonia was performed in 34 cases that developing BO and 105 cases not developing BO in Children's hospital of Chongqing Medical University from January 2015 to February 2019. The multivariate logistic regression analysis was used to identify factors which were significantly associated with development of BO after the univariate analysis, and receiver operating characteristic (ROC) curve analysis was performed to find out the cut-off value for the significant relevant factors. A nonlinear dose-response relationship between risk factors and the risk of BO was assessed by restricted cubic spline model. Three factors were independently associated with development of BO, which were length of fever (OR 1.129, 95% CI 1.033-1.234), dyspnea (OR 3.922, 95% CI 1.060-14.514) and invasive mechanical ventilation (OR 6.861, 95% CI 1.854-25.387). The cut-off value of length of fever were 10.5 days. A linear dose-response relationship between length of fever and occurrence of BO was observed (P = .57 for nonlinearity). Children with severe adenovirus pneumonia who have a longer duration of fever (especially more than 10.5 days), have dyspnea or require invasive mechanical ventilation in the acute phase are more likely to develop BO.

Cryobiopsy in the diagnosis of bronchiolitis: a retrospective analysis of twenty-three consecutive patients

Bronchiolitis manifests as a variety of histological features that explain the complex clinical profiles and imaging aspects. In the period between January 2011 and June 2015, patients with a cryobiopsy diagnosis of bronchiolitis were retrospectively retrieved from the database of our institution. Clinical profiles, imaging features and histologic diagnoses were analysed to identify the role of cryobiopsy in the diagnostic process. Twenty-three patients with a multidisciplinary diagnosis of small airway disease were retrieved (14 females, 9 males; age range 31-74 years old; mean age 54.2 years old). The final MDT diagnoses were post-infectious bronchiolitis (n = 5), constrictive bronchiolitis (n = 3), DIPNECH (n = 1), idiopathic follicular bronchiolitis (n = 3), Sjogren's disease (n = 1), GLILD (n = 1), smoking-related interstitial lung disease (n = 6), sarcoid with granulomatous bronchiolar disorder (n = 1), and subacute hypersensitivity pneumonitis (n = 2). Complications reported after the cryobiopsy procedure consisted of two cases of pneumothorax soon after the biopsy (8.7%), which were successfully managed with the insertion of a chest tube. Transbronchial cryobiopsy represents a robust and mini-invasive method in the characterization of small airway diseases, allowing a low percentage of complications and good diagnostic confidence.

Acute Lung Injury and Non-infectious Pneumonias

Lung injury can occur secondary to a myriad of causes, including infection, immunologic disorders, drug toxicity, or inhalational injury among others. Although the list of causative agents is long, the lung’s response to injury is limited resulting in similar patterns of disease irrespective of the cause. From a pathological perspective, acute lung injury refers to a group of entities that present with acute or subacute disease. These conditions are characterized by particular histological patterns including diffuse alveolar damage, acute fibrinous and organizing pneumonia, organizing pneumonia, and eosinophilic pneumonia and clinically correspond to the varying degrees of acute respiratory distress syndrome (Patel et al, Chest 125:197–202, 2004; Beasley et al, Arch Pathol Lab Med 126:1064–1070, 2002; Avecillas et al, Clin Chest Med 27:549–557, 2006; Cottin, Cordier, Semin Respir Crit Care Med 33:462–475, 2012; Ferguson et al, Intensive Care Med 38:1573–1582, 2012). In most cases, the underlying cause will not be apparent from the histological findings requiring close correlation with clinical history and laboratory findings to determine the etiology. Nevertheless, careful search for infectious organisms with application of histochemical and immunohistochemical stains should be performed in all cases in order to identify cases that benefit from more targeted treatment.

Perspectives in veterinary medicine: Description and classification of bronchiolar disorders in cats

This Perspectives in Veterinary Medicine article seeks to define, describe putative causes, and discuss key diagnostic tests for primary and secondary bronchiolar disorders to propose a classification scheme in cats with support from a literature review and case examples. The small airways (bronchioles with inner diameters <2 mm), located at the transitional zone between larger conducting airways and the pulmonary acinus, have been overlooked as major contributors to clinical syndromes of respiratory disease in cats. Because the trigger for many bronchiolar disorders is environmental and humans live in a shared environment with similar susceptibility, understanding these diseases in pet cats has relevance to One Health. Thoracic radiography, the major imaging modality used in the diagnostic evaluation of respiratory disease in cats, has low utility in detection of bronchiolar disease. Computed tomography (CT) with paired inspiratory and expiratory scans can detect pathology centered on small airways. In humans, treatment of bronchiolar disorders is not well established because of heterogeneous presentations and often late definitive diagnosis. A review of the human and veterinary medical literature will serve as the basis for a proposed classification scheme in cats. A case series of cats with CT or histopathologic evidence of bronchiolar lesions or both, either as a primary disorder or secondary to extension from large airway disease or interstitial lung disease, will be presented. Future multi‐institutional and multidisciplinary discussions among clinicians, radiologists, and pathologists will help refine and develop this classification scheme to promote early and specific recognition and optimize treatment.

Diagnosing and managing bronchiolitis obliterans in children

INTRODUCTION

Bronchiolitis obliterans (BO) is a chronic and irreversible obstructive lung disease leading to the obstruction and/or obliteration of the small airways. Three main BO entities are distinguished: post-infectious BO (PIBO); BO post lung transplantation; and BO after bone marrow transplantation (BMT) or hematopoietic stem cell transplantation (HSCT). All three entities are separate, however, there are similarities in histopathological characteristics and possibly in aspects of the development pathway. Areas covered: We review current evidence of bronchiolitis obliterans diagnosis and management in children. The diagnosis of BO is usually based on a combination of history, clinical and radiological findings, although lung biopsy and histopathology remain the gold standard approaches to confirm BO. Expert opinion: At present, we do not have a clear understanding of the mechanisms of the development of BO and lack strong evidence for treatment. Although most BO in children is post-infectious, most of the current evidence for treatment originates from studies analyzing BO in adult lung transplant and HSCT patients. BO management requires multidisciplinary approach and care in specialized centers.

Post-infectious bronchiolitis obliterans

Bronchiolitis obliterans is a rare and severe chronic lung disease resulting from a lower respiratory tract lesion. It may occur after a bone marrow or lung transplantation, infectious diseases, or less frequently after inhaling toxic substances or after connective tissue diseases. Pathology, pathogenesis, and molecular biology, as well as the best treatment of bronchiolitis obliterans, remain the subject of ongoing research. This review discusses our current knowledge of different areas of bronchiolitis obliterans associated with infectious lesions.

Bronchiolitis obliterans murine model induced by nitric acid aerosol inhalation: An economical and reproducible model

PURPOSE

Bronchiolitis obliterans (BO) is a highly debilitative and fatal syndrome associated with a series of severe lower airway disorders. The pathogenesis of BO is complicated and not entirely understood. An appropriate animal model of BO may aid research into its pathogenesis. Here, we establish a mouse model of BO to provide insight into this disease.

MATERIALS AND METHODS

6-8 week old BABL/c mice were exposed to 5% nitric acid (NA) aerosol through a nebulizer for 3 hours, and controls were exposed to distilled water instead. Symptoms, airway resistance and pathological process were observed dynamically. The levels of matrix metalloproteinase-2 (MMP-2), MMP-9, tissue inhibitor of metalloproteinase-1 (TIMP-1), 8-isoprostane and myeloperoxidase (MPO) in lung tissue and bronchoalveolar lavage fluids (BLAF) were determined by ELISA on day 3, 7, 14, 28 and 56 after the aerosol nebulization.

RESULTS

Typical BO lesions were observed in NA nebulized mice characterized histologically by initial necrotizing bronchiolitis and final airway fibrosis at day 28 after the aerosol nebulization. NA nebulized mice also exhibited labored breathing and significantly increased airway resistance. Expression of MMP-2, MMP-9, TIMP-1, 8-isoprostane and MPO were significantly elevated in NA nebulized mice in different time frame.

CONCLUSION

A murine BO model was established by NA aerosol inhalation. It provides an easy, economic, and reproducible mice model for BO research.

Successful treatment of suspected organizing pneumonia in a patient without typical imaging and pathological characteristic: A case report

Introduction

Organizing pneumonia (OP) is a clinicopathological entity characterized by granulation tissue plugs in the lumen of small airways, alveolar ducts, and alveoli. Diagnosis of OP needs the combination of clinical features, imaging and pathology. But it occurs often that there are no typical pathological features to support the diagnosis, which poses a challenge for clinicians' diagnosis and treatment. We diagnosed a case of OP without typical imaging and pathological characteristic and treated successfully. Finally we confirmed the pathological diagnosis.

Conclusions

Not every OP case is supported by pathological evidence and typical imaging changes. It is important for us to judge and decide the diagnosis according to clinical experience.

Organizing Pneumonia in Rheumatoid Arthritis Patients: A Case-Based Review

We treated 21 patients with organizing pneumonia (OP) associated with rheumatoid arthritis (RA) or related to biological disease-modifying antirheumatic drugs (DMARDs) at our institution between 2006 and 2014. Among these cases, 3 (14.3%) preceded articular symptoms of RA, 4 (19.0%) developed simultaneously with RA onset, and 14 (66.7%) occurred during follow-up periods for RA. In the case of OP preceding RA, increased levels of anti-cyclic citrullinated peptide antibodies and rheumatoid factor were observed at the OP onset. RA disease activity was related to the development of OP in the simultaneous cases. In the cases of OP developing after RA diagnosis, 10 of 14 patients had maintained low disease activity with biological DMARD therapy at the OP onset, and among them, 6 patients developed OP within the first year of this therapy. In the remaining four patients, RA activity was not controlled at the OP onset. All patients responded well to systemic steroid therapy, but two patients suffered from relapses of articular and pulmonary symptoms upon steroid tapering. In most of the RA patients, DMARD therapy was introduced or restarted during the steroid tapering. We successfully restarted a biological DMARD that had not been previously used for patients whose RA would otherwise have been difficult to control. In this study, we also perform a review of the literature on RA-associated or biological DMARD-related OP and discuss the pathogenesis and management of OP occurring in RA patients.

Chronic obstructive pulmonary diseases in children

OBJECTIVES

To verify and describe the main events related to the diagnosis and management of chronic obstructive pulmonary diseases in children (COPDC) and adolescents, considering the interrelated physiopathology, genetic, and environmental characteristics.

SOURCES

Relevant literature from PubMed was selected and reviewed.

SUMMARY OF THE FINDINGS

COPDC have an environmental and/or genetic origin and its manifestation has manifold genotypes, phenotypes, and endotypes. Although COPDC has no cure, it can be clinically controlled. Chronic cough is the main symptom and bronchiectasis can be present in several COPDC patients. The management of COPDC is more effective if based on guidelines and when treatment regimen adherence is promoted. Oral and inhaled corticosteroids, bronchodilators, inhaled antibiotics, and treatment of pulmonary exacerbation (PE) are the bases of COPDC management, and should be individualized for each patient.

CONCLUSIONS

Correct diagnosis and knowledge of risk factors and comorbidities are essential in COPDC management. Procedures and drugs used should be based on specific guidelines for each COPDC case. Treatment adherence is critical to obtain the benefits of management. COPDC clinical control must be evaluated by the decrease in PEs, improved quality of life, reduction of pulmonary function loss, and lung structural damage. For most cases of COPDC, monitoring by interdisciplinary teams in specialized reference centers with surveillance strategies and continuous care leads to better outcomes, which must be evaluated by decreasing pulmonary function damage and deterioration, better prognosis, better quality life, and increased life expectancy.

Adult bronchiolitis--a clinical and pathological interpretative classification

INTRODUCTION

Bronchiolitis is a heterogeneous group of diseases of an inflammatory nature, centered on small conducting airways and often associated with other pulmonary disorders. No single classification scheme for bronchiolar diseases has been widely accepted. In this retrospective study, it was decided to apply a new clinical and pathological interpretative classification.

OBJECTIVES

To propose a new clinical and pathological interpretative classification for adult bronchiolitis, based on statistical analysis of a population of 193 patients with histopathological diagnosis of bronchiolitis.

MATERIALS AND METHODS

A retrospective study analyzed the epidemiological characteristics, co-morbidities and radiological findings present in a group of patients with histopathological diagnosis of bronchiolitis.

RESULTS

This trial involved 193 cases collected over a period of eleven years; 48 (24.9%) patients had simultaneous pulmonary disease; non-pulmonary diseases, such as cardiovascular diseases, type II Diabetes mellitus and dyslipidemia were present in 57 cases. The image study was extremely important in order to integrate clinical and pathological aspects. In this study respiratory bronchiolitis related to smoking dominated. The radiological findings confirmed the secondary nature of the histopathological features, with prevalence of ground-glass patterns, pneumothorax and patterns of interstitial involvement, as described in the literature. It was also verified that clinical behavior of different forms of bronchiolitis was important to distinguish the various types, since they could progress without typical anatomopathological aspects.

CONCLUSION

This trial showed that the vast majority of diagnosis obtained corresponded to bronchiolitis as secondary to pulmonary pathology. In most cases, morphological findings had to be complemented with clinical and radiological characteristics, in order to obtain the final diagnosis.

Airway inflammation in children and adolescents with bronchiolitis obliterans

BACKGROUND

Airway inflammation plays a major role in the progression of chronic lung diseases. The features of airway inflammation are not well defined among patients with cases of bronchiolitis obliterans (BO) that began in childhood.

OBJECTIVES

To investigate the sputum cell and cytokine profiles of stable cases of BO regarding lung function and the involvement of small airway disease (SAD).

METHODS

Twenty patients with BO (median age=14.5, range=7-23years) and 22 healthy controls (median age=16.5years, range=7-24years) were investigated. Lung function parameters and bronchial reversibility testing as well as sputum cell and cytokine profiles (IL-1β, IL-6, IL-8, TNF-α, IL-5, IFN-γ, and NFκB regulation) were analysed using quantitative RT-PCR and cytometric bead assay (CBA) in induced sputum.

RESULTS

Patients with BO had significantly lower lung function values, including FVC, forced expiratory volume (FEV1), the Tiffeneau index (FEV1/VC), and MEF25, but increased functional residual capacity (RV/TLC) values. Bronchial reversibility was found in five patients (25%). Moreover, airway inflammation (as indicated by total cells, neutrophils, IL-1β, IL-6, IL-8, TNF-α, and NFκB) was significantly increased among patients with BO compared with controls.

CONCLUSIONS

BO is predominantly a neutrophilic disease of the small bronchioles featuring elevated levels of pro-inflammatory cytokines leading to tissue remodelling and fibrosis of the small airways. Future therapies for patients with BO should more efficiently target the small airways.

Airspace-Occupying Diseases

Diseases of the air space of the lung share many common findings and presentation that it makes more sense to be grouped together in a differential diagnosis. The common imaging finding is usually as a lung infiltrate or consolidation of some type of distribution or another. Trying to find the putative cause for the imaging pattern is a good first step in narrowing the differential diagnosis and answering the question: what accounts for this pattern on imaging studies? Most of these diseases have an acute or subacute onset and exhibit restrictive pattern on pulmonary function tests. When treated promptly, they resolve completely with little or no residual injury to the lung architecture.

On a small biopsy it is important to have a clinical history and imaging results before embarking on a descriptive rather than a definitive diagnosis. The smaller the sample, the more information is needed to complete the picture. Pulmonologists should be advised to target the part of the lung that should provide the most information related to the process under investigation. An endobronchial wall biopsy is not suitable in the setting of investigating a lung infiltrate as part of the alveolated lung has to be included.

The category of airspace-occupying diseases of the lung includes:

Acute lung infections such as bacterial and viral pneumonias

Acute lung injury pattern which includes bronchiolitis obliterans/organizing pneumonia and diffuse alveolar damage

Intra-alveolar hemorrhage

Pulmonary alveolar proteinosis

Pulmonary edema

Pneumocystis pneumonia

Lymphangitic carcinomatosis

In all of these instances, there are ground-glass opacities obscuring the air space. Most clinicians would describe the imaging as “infiltrate” or “consolidation.” The task for the pathologist is to find the pertinent finding that could account for the imaging.

Study of active duty military for pulmonary disease related to environmental deployment exposures (STAMPEDE)

RATIONALE

Because of increased levels of airborne particulate matter in Southwest Asia, deployed military personnel are at risk for developing acute and chronic lung diseases. Increased respiratory symptoms are reported, but limited data exist on reported lung diseases.

OBJECTIVES

To evaluate new respiratory complaints in military personnel returning from Southwest Asia to determine potential etiologies for symptoms.

METHODS

Returning military personnel underwent a prospective standardized evaluation for deployment-related respiratory symptoms within 6 months of returning to their duty station.

MEASUREMENTS AND MAIN RESULTS

Prospective standardized evaluation included full pulmonary function testing, high-resolution chest tomography, methacholine challenge testing, and fiberoptic bronchoscopy with bronchoalveolar lavage. Other procedures including lung biopsy were performed if clinically indicated. Fifty patients completed the study procedures. A large percentage (42%) remained undiagnosed, including 12% with normal testing and an isolated increase in lavage neutrophils or lymphocytes. Twenty (40%) patients demonstrated some evidence of airway hyperreactivity to include eight who met asthma criteria and two with findings secondary to gastroesophageal reflux. Four (8%) additional patients had isolated reduced diffusing capacity and the remaining six had other miscellaneous airway disorders. No patients were identified with diffuse parenchymal disease on the basis of computed tomography imaging. A significant number (66%) of this cohort had underlying mental health and sleep disorders.

CONCLUSIONS

Evaluation of new respiratory symptoms in military personnel after service in Southwest Asia should focus on airway hyperreactivity from exposures to higher levels of ambient particulate matter. These patients may be difficult to diagnose and require close follow-up.

Approach to Lung Biopsies From Patients With Pneumothorax

Context.—Patients with pneumothorax occasionally require limited lung resections to control persistent air leaks. In some patients, especially smokers, histopathologic findings suggest that a ruptured bulla or bleb caused the pneumothorax. Other patients only exhibit histopathologic changes related to the physical trauma of acute, and likely occult recurrent, peripheral lung injury in the setting of “spontaneous,” or idiopathic, lung rupture. Sometimes, pneumothorax occurs secondary to an underlying localized or diffuse parenchymal lung disease. A comprehensive description of the morphologic findings that may be seen in these specimens will help the surgical pathologist distinguish patients with more common and indolent occurrences of pneumothorax from those requiring additional workup or treatment.

Objective.—To develop a diagnostic approach for surgical pathologists encountering lung specimens obtained in the context of pneumothorax repair.

Data Sources.—Literature review and consultation experience of the authors.

Conclusions.—Two general categories of histopathologic changes can be identified: (1) nonspecific changes, reflecting the lung's acute and chronic response to localized injury, and (2) changes suggesting an underlying lung disease that may have played an etiologic role in the development of pneumothorax. The latter changes are important to recognize because they may require additional workup or treatment of clinically occult lung disease. Difficulty arises when nonspecific histopathologic changes overlap with those of an underlying lung disease. Awareness of these diagnostic challenges and pitfalls, together with clinicoradiographic correlation, is essential in these situations and will help guide the surgical pathologist toward an accurate diagnosis and the appropriate management of clinically occult disease.

The idiopathic interstitial pneumonias: an update and review

Idiopathic interstitial pneumonias (IIPs) are a group of disorders with distinct histologic and radiologic appearances and no identifiable cause. The IIPs comprise 8 currently recognized entities. Each of these entities demonstrates a prototypical imaging and histologic pattern, although in practice the imaging patterns may overlap, and some interstitial pneumonias are not classifiable. To be considered an IIP, the disease must be idiopathic; however, each pattern may be secondary to a recognizable cause, most notably collagen vascular disease, hypersensitivity pneumonitis, or drug reactions. The diagnosis of IIP requires the correlation of clinical, imaging, and pathologic features.

Pulmonary manifestations of Sjögren's syndrome

Sjögren's syndrome (SS) is primarily defined by its impact on the oral and ocular system resulting in xerostomia and xerophthalmia. However, SS can also manifest throughout the respiratory system. Subclinical pulmonary involvement is common. Clinically significant involvement can result in a 4-fold increased risk of death. Thus, recognizing the many potential presentations of SS in the lung is critical in caring for patients with SS. Additionally, SS should be included in the differential diagnosis of a number of forms of interstitial lung disease.

Diagnosis and management of chronic lung disease in deployed military personnel

Military personnel are a unique group of individuals referred to the pulmonary physician for evaluation. Despite accession standards that limit entrance into the military for individuals with various pre-existing lung diseases, the most common disorders found in the general population such as asthma and chronic obstructive pulmonary disease remain frequently diagnosed. Military personnel generally tend to be a more physically fit population who are required to exercise on a regular basis and as such may have earlier presentations of disease than their civilian counterparts. Exertional dyspnea is a common complaint; establishing a diagnosis may be challenging given the subtle nature of symptoms and lack of specificity with pulmonary function testing. The conflicts over the past 10 years in Iraq and Afghanistan have also given rise to new challenges for deployed military. Various respiratory hazards in the deployed environment include suspended geologic dusts, burn pits, vehicle exhaust emissions, industrial air pollution, and isolated exposure incidents and may give rise to both acute respiratory symptoms and chronic lung disease. In the evaluation of deployed military personnel, establishing the presence of actual pulmonary disease and the relationship of existing disease to deployment is an ongoing issue to both military and civilian physicians. This paper reviews the current evidence for chronic lung disease in the deployed military population and addresses any differences in diagnosis and management.

[Post-infectious bronchiolitis obliterans]

Post-infectious bronchiolitis obliterans (BO) is characterized by inflammatory and fibrotic lesions of small airways following a pulmonary infection and leading to some degree of airway obstruction. It represents a rare cause of chronic obstructive pulmonary disease, and is probably underestimated, especially when the lesions affect small areas of the lungs. The clinical features differ between children and adults. In children, adenovirus is the most frequently involved infectious agent, especially the more virulent serotypes 3, 7 and 21. The clinical and radiological signs vary widely and the functional outcome depends on the extent of the lung injury. The diagnosis is based on the medical history, the CT-scan and functional data. The treatment is symptomatic. The most severe forms may result in chronic respiratory insufficiency. In adults, the frequency of obstructive injuries of the small airways in the context of lung infection is unclear. Parenchymal lesions are often present, resulting in BO with organizing pneumonia. These lesions alter the clinical presentation and the radiographic features of the initial infectious disease and often prove difficult to diagnose and manage. Several authors have published clinical cases describing presumed efficacy of systemic corticosteroids but the data are scarce.

Organizing pneumonia in recipients of hematopoietic stem cell transplantation: CT features in 16 patients

PURPOSE

To evaluate computed tomographic (CT) scans of patients with organizing pneumonia (OP) complicating hematopoietic stem cell transplantation (HSCT).

MATERIALS AND METHODS

A review of patients who underwent HSCT at our institution identified 16 patients who had documented OP on biopsy. Computed tomographic scans were reviewed by 2 thoracic radiologists.

RESULTS

Ground glass opacities (GGO) were seen in 15 patients, consolidation in 8 patients, linear opacities in 8 patients, traction bronchiectasis in 2 patients, and septal thickening in 2 patients. Ground glass opacity was the dominant abnormality in 7 patients, consolidation in 4 patients, and linear opacities in 5 patients. Peribronchovascular distribution was found in 4 patients, peripheral in 2 patients, diffuse in 3 patients; upper lung predominance was found in 10 patients, and lower lung predominance in 5 patients.

CONCLUSION

The principal computed tomographic features of OP after HSCT are ground glass opacities, consolidation and linear opacities, with upper lung predominance. Allowing for a possible sampling bias, these findings differ from those reported in cryptogenic OP and OP from other causes.

Cryptogenic Organizing Pneumonia in Tomm5–/– Mice

Almost all mitochondrial proteins are encoded in the nuclear DNA and synthesized in the cytosol as pre-proteins. There is a protein translocase located in the mitochondrial outer membrane that transports mitochondrial pre-proteins into mitochondria. The central component of this translocase of the outer mitochondrial membrane (TOMM) complex is TOMM40, and TOMM5 is one of three small subunits associated with TOMM40. Translocase of outer mitochondrial membrane 5 homolog ( Tomm5–/–) knockout mice demonstrated an unexpected lung-specific phenotype characterized by widespread intra-alveolar fibrosis. Although TOMM5-deficient mice tested normal in a very broad range of phenotyping assays, they displayed histopathological lesions in the lung that were consistent with those reported in humans with cryptogenic organizing pneumonia (COP), which is also known as bronchiolitis obliterans organizing pneumonia (BOOP). The lesions had a patchy distribution in the lung and were characterized by the presence of intraluminal fibrogenic buds consisting of fibroblasts and myofibroblasts embedded in a loose connective tissue matrix that occupied the lumina of alveoli and alveolar ducts, with preservation of underlying alveolar architecture. In addition to macrophages, which were numerous in affected and surrounding alveoli, eosinophils comprised the most common and widespread inflammatory cell. Taken together, the findings in Tomm5–/– mice provide yet another example of the value of histopathology as a baseline assay in high-throughput phenotyping systems.

Irritant-induced airway disorders

Thousands of persons experience accidental high-level irritant exposures each year but most recover and few die. Irritants function differently than allergens because their actions proceed nonspecifically and by nonimmunologic mechanisms. For some individuals, the consequence of a single massive exposure to an irritant, gas, vapor or fume is persistent airway hyperresponsiveness and the clinical picture of asthma, referred to as reactive airways dysfunction syndrome (RADS). Repeated irritant exposures may lead to chronic cough and continual airway hyperresponsiveness. Cases of asthma attributed to repeated irritant-exposures may be the result of genetic and/or host factors.

The evolving spectrum of pulmonary disease in responders to the World Trade Center tragedy

On September 11, 2001, events at the World Trade Center (WTC) exposed residents ofNew York City to WTC dust and products of combustion and pyrolysis. The majority ofWTC-exposed fire department rescue workers experienced a substantial decline in airflowover the first 12 months post-9/11, in addition to the normal age-related declinethat affected all responders, followed by a persistent plateau in pulmonary function inthe 6 years thereafter. The spectrum of the resulting pulmonary diseases consists ofchronic inflammation, characterized by airflow obstruction, and expressing itself indifferent ways in large and small airways. These conditions include irritant-inducedasthma, non-specific chronic bronchitis, aggravated pre-existing obstructive lung disease(asthma or COPD), and bronchiolitis. Conditions concomitant with airwaysobstruction, particularly chronic rhinosinusitis and upper airway disease, and gastroesophagealreflux, have been prominent in this population. Less common have beenreports of sarcoidosis or interstitial pulmonary fibrosis. Pulmonary fibrosis and bronchiolitisare generally characterized by long latency, relatively slow progression, and asilent period with respect to pulmonary function during its evolution. For these reasons,the incidence of these outcomes may be underestimated and may increase overtime. The spectrum of chronic obstructive airways disease is broad in this populationand may importantly include involvement at the bronchiolar level, manifested as smallairways disease. Protocols that go beyond conventional screening pulmonary functiontesting and imaging may be necessary to identify these diseases in order to understandthe underlying pathologic processes so that treatment can be most effective.

The lung in rheumatoid arthritis

Rheumatoid arthritis (RA) is a common inflammatory disease, affecting about 1% of the population. Although a major portion of the disease burden including excess mortality is due to its extra-articular manifestations, the prevalence of RA-associated lung disease is increasing. RA can affect the lung parenchyma, airways, and the pleura; and pulmonary complications are directly responsible for 10 to 20% of all mortality. Even though pulmonary infection and drug toxicity are frequent complications of RA, lung disease directly associated with the underlying RA is more common. The prevalence of a particular complication varies based on the characteristics of the population studied, the definition of lung disease used, and the sensitivity of the clinical investigations employed. An overview of lung disease associated with RA is presented here with an emphasis on parenchymal lung disease, pleural effusion, and airway involvement.

Kikuchi Fujimoto disease associated with cryptogenic organizing pneumonia: case report and literature review

Background

The association of Kikuchi Fujimoto disease (KFD) with cryptogenic organizing pneumonia (COP) is extremely rare. We report a case of simultaneous diagnosis of KFD and COP.

Case Presentation

A 33-year-old male presented with a 1-month cough illness and fever lasting for 5 days. The chest radiograph revealed double lower lobe infiltrate, which was unresponsive to antibiotics. A cervical lymph node was first found in the development of this disease. Bronchoscopy, bronchoalveolar lavage and lung biopsy established the diagnosis of COP, while a lymph node biopsy was consistent with KFD. The patient improved on steroids.

Conclusions

KFD and COP are possible part of a disease continuum, rather than separate entities.

Small Airways Disease

Small airways diseases are best defined pathologically as a diverse group of conditions that primarily involve bronchioles and acartilagenous airways 2 mm or less in diameter, which include membranous bronchioles, respiratory bronchioles, and alveolar ducts. Small airways can be involved with disease primarily or secondarily. The concept of small airways disease varies among specialties, with clinicians generally considering them in terms of terminal airway changes causing airflow obstruction, radiologists considering them in the context of direct signs and indirect signs identified on high-resolution computed tomography scans, and pathologists evaluating them based entirely or almost entirely on the histologic changes present in the bronchioles, with or without associated changes involving bronchi and alveoli. The histologic features of small airways diseases may be confusing because they overlap. There may be incomplete assessment of the histologic process with limited biopsy. Other disease processes may occur along with a small airways disease, and may obscure or confound its histologic features. This article focuses on the histologic changes diagnostic of a variety of primary and secondary small airways diseases. Because the histologic features involve bronchioles, gross findings are often minimal and/or nonspecific. The article provides a nonexhaustive examination of conditions and diseases involving the small airways, focusing on the microscopic features, with emphasis on the limitations of histologic diagnosis and differential diagnosis.

Clinical prediction rule to diagnose post-infectious bronchiolitis obliterans in children

RATIONALE

Infant pulmonary function testing has a great value in the diagnosis of post-infectious bronchiolitis obliterans (BOs), because of characteristic patterns of severe and fixed airway obstruction. Unfortunately, infant pulmonary function testing is not available in most pediatric pulmonary centers.

OBJECTIVE

To develop and validate a clinical prediction rule (BO-Score) to diagnose children under 2 years of age with BOs, using multiple objectively measured parameters readily available in most medical centers.

METHODS

Study subjects, children under 2 years old with a chronic pulmonary disease assisted at R. Gutierrez Children's Hospital of Buenos Aires. Patients were randomly divided into a derivation (66%) and a validation (34%) set. ROC analyses and multivariable logistic regression included significant clinical, radiological, and laboratory predictors. The main outcome measure was a diagnosis of BOs. The performance of the BO-Score was tested on the validation set.

RESULTS

Hundred twenty-five patients were included, 83 in the derivation set and 42 in the validation set. The BO-Score (area under ROC curve = 0.96; 95% CI, 0.9-1.0%) was developed by assigning points to the following variables: typical clinical history (four points), adenovirus infection (three points), and high-resolution computed tomography with mosaic perfusion (four points). A Score > or =7 predicted the diagnosis of BOs with a specificity of 100% (95% CI, 79-100%) and a sensitivity of 67% (95% CI, 47-80%).

CONCLUSIONS

The BO-Score is a simple-to-use clinical prediction rule, based on variables that are readily available. A BO-Score of 7 or more predicts a diagnosis of post-infectious BOs with high accuracy.

Diffuse panbronchiolitis: not just an Asian disease: Australian case series and review of the literature

Diffuse panbronchiolitis is a disease of obscure aetiology that is traditionally associated with Asian ethnicity. We propose that this disease also occurs in Caucasians and the incidence in this population is greater than currently recognised. We further propose that high resolution computed tomography (HRCT) and response to macrolide therapy should be relied upon to make this diagnosis without verification by lung biopsy. In most circumstances, obtaining a biopsy for histopathology is not practical, and the disease may then be mistaken for other more common airway diseases. Accuracy of diagnosis is important as untreated disease is associated with a poor prognosis, and effective treatment is available. We report four out of a series of cases as evidence that DPB is in fact more common in the Western population than is currently understood.