Obstructive lung diseases: COPD, asthma, and many imitators

Rapid FEV1/FVC Decline Is Related With Incidence of Obstructive Lung Disease and Mortality in General Population

BACKGROUND

Forced expiratory volume in 1 second (FEV₁)/forced vital capacity (FVC) naturally decreases with age; however, an excessive decline may be related with increased morbidity and mortality. This study aimed to evaluate the FEV₁/FVC decline rate in the Korean general population and to identify whether rapid FEV₁/FVC decline is a risk factor for obstructive lung disease (OLD) and all-cause and respiratory mortality.

METHODS

We evaluated individuals aged 40-69 years who underwent baseline and biannual follow-up spirometric assessments for up to 18 years, excluding those with airflow limitations at baseline. Based on the quartiles of the annual FEV₁/FVC decline rate, the most negative FEV₁/FVC change (1^st quartile of annual FEV₁/FVC decline rate) was classified as rapid FEV₁/FVC decline. We investigated the risk of progression to OLD and all-cause and respiratory mortality in individuals with rapid FEV₁/FVC decline.

RESULTS

The annual FEV₁/FVC decline rate in the eligible 7,768 patients was 0.32 percentage point/year. The incidence rate of OLD was significantly higher in patients with rapid FEV₁/FVC decline than in those with non-rapid FEV₁/FVC decline (adjusted incidence rate, 2.119; 95% confidence interval [CI], 1.932-2.324). Rapid FEV₁/FVC decline was an independent risk factor for all-cause mortality (adjusted hazard [HR], 1.374; 95% CI, 1.105-1.709) and respiratory mortality (adjusted HR, 1.353; 95% CI, 1.089-1.680).

CONCLUSION

The annual FEV₁/FVC decline rate was 0.32%p in the general population in Korea. The incidence rate of OLD and the hazards of all-cause and respiratory mortality were increased in rapid FEV₁/FVC decliners.

Recent advances in the understanding of bronchiolitis in adults

Bronchiolitis is injury to the bronchioles (small airways with a diameter of 2 mm or less) resulting in inflammation and/or fibrosis. Bronchioles can be involved in pathologic processes that involve predominantly the lung parenchyma or large airways, but, in some diseases, bronchioles are the main site of injury ("primary bronchiolitis"). Acute bronchiolitis caused by viruses is responsible for most cases of bronchiolitis in infants and children. In adults, however, there is a wide spectrum of bronchiolar disorders and most are chronic. Many forms of bronchiolitis have been described in the literature, and the terminology in this regard remains confusing. In clinical practice, a classification scheme based on the underlying histopathologic pattern (correlates with presenting radiologic abnormalities) facilitates the recognition of bronchiolitis and the search for the inciting cause of the lung injury. Respiratory bronchiolitis is the most common form of bronchiolitis in adults and is usually related to cigarette smoking. Currently, the diagnosis of respiratory bronchiolitis is generally achieved based on the clinical context (smoking history) and chest CT findings. Constrictive (obliterative) bronchiolitis is associated with airflow obstruction and is seen in various clinical contexts including environmental/occupational inhalation exposures, transplant recipients (bronchiolitis obliterans syndrome), and many others. Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is increasingly recognized and can be associated with progressive airflow obstruction related to constrictive bronchiolitis ("DIPNECH syndrome"). Diffuse aspiration bronchiolitis is a form of aspiration-related lung disease that is often unsuspected and confused for interstitial lung disease. Novel forms of bronchiolitis have been described, including lymphocytic bronchiolitis and alveolar ductitis with emphysema recently described in employees at a manufacturing facility for industrial machines. Bronchiolitis is also a component of vaping-related lung injury encountered in the recent outbreak.

Validity and Reliability of the Turkish Version of the London Chest Activity of Daily Living Scale in Obstructive Lung Diseases

OBJECTIVES

The London Chest Activity of Daily Living Scale (LCADL) is a simple, useful, and comprehensive measure of dyspnea perception in activities of daily living. This study was conducted to determine the validity and reliability of the Turkish version of the LCADL.

MATERIALS AND METHODS

A total of 64 patients with obstructive lung disease (24 chronic obstructive pulmonary disease, 20 asthma, and 20 bronchiectasis patients) were included. The Turkish LCADL was evaluated for interobserver reliability, test-retest reliability, and criterion validity. Two different observers applied the scale with an interval of 10 minutes to assess interobserver reliability. The second observer applied the scale twice at an interval of 10-15 days to assess test-retest reliability. Criterion validity was assessed using the 6-minute walk test (6MWT), Nottingham Health Profile (NHP), and Saint George Respiratory Questionnaire (SGRQ).

RESULTS

The interobserver reliability of the scale was very high (r_s=0.985, p<0.050). Cronbach's alpha coefficient for total score was 0.976 and intraclass correlation coefficient was 0.953. These results indicate that the Turkish LCADL has high reliability. The correlation between LCADL and 6MWT was moderate 0.503 (p=0.002). The LCADL total score was weakly correlated with NHP total score (r_s=0.370, p=0.040) and SGRQ total score (r_s=0.367, p=0.004).

CONCLUSION

The Turkish version of the LCADL scale is reliable and valid in obstructive lung disease. The LCADL scale will be beneficial in existing pulmonary rehabilitation programs aiming to improve functional status. We believe that using the Turkish LCADL scale as an outcome measure in pulmonary rehabilitation programs will serve as an indicator of rehabilitation efficacy for individual patients.

Imaging of Asthma

Asthma is one of the most common diseases of the lung. Asthma manifests with common, although often subjective and nonspecific, imaging features at radiography and high-resolution computed tomography. The primary role of imaging is not to make a diagnosis of asthma but to identify complications, such as allergic bronchopulmonary aspergillosis, or mimics of asthma, such as hypersensitivity pneumonitis. This article reviews the imaging features of asthma as well as common complications and mimics.

Lung volumes and airway resistance in patients with a possible restrictive pattern on spirometry

Objective:

Many patients with proportional reductions in FVC and FEV1 on spirometry show no reduction in TLC. The aim of this study was to evaluate the role that measuring lung volumes and airway resistance plays in the correct classification of patients with a possible restrictive pattern on spirometry.

Methods:

This was a prospective study involving adults with reduced FVC and FEV1, as well as an FEV1/FV(C) ratio within the predicted range. Restrictive lung disease (RLD) was characterized by TLC below the 5th percentile, as determined by plethysmography. Obstructive lung disease (OLD) was characterized by high specific airway resistance, significant changes in post-bronchodilator FEV1, or an FEF25-75% < 50% of predicted, together with a high RV/TLC ratio. Nonspecific lung disease (NLD) was characterized by TLC within the predicted range and no obstruction. Combined lung disease (CLD) was characterized by reduced TLC and findings indicative of airflow obstruction. Clinical diagnoses were based on clinical suspicion, a respiratory questionnaire, and the review of tests of interest.

Results:

We included 300 patients in the study, of whom 108 (36%) were diagnosed with RLD. In addition, 120 (40%) and 72 (24%) were diagnosed with OLD/CLD and NLD, respectively. Among the latter, 24 (33%) were clinically diagnosed with OLD. In this sample, 151 patients (50.3%) were obese, and obesity was associated with all patterns of lung disease.

Conclusions:

Measuring lung volumes and airway resistance is often necessary in order to provide an appropriate characterization of the pattern of lung disease in patients presenting with a spirometry pattern suggestive of restriction. Airflow obstruction is common in such cases.

Objetivo:

Muitos pacientes com redução proporcional de CVF e VEF1 na espirometria não têm CPT reduzida. O objetivo deste estudo foi avaliar o papel da medida dos volumes pulmonares e da resistência das vias aéreas para a classificação correta de pacientes com possível restrição à espirometria.

Métodos:

Estudo prospectivo de adultos com CVF e VEF1 reduzidos e relação VEF1/CV(F) na faixa prevista. Distúrbio ventilatório restritivo (DVR) foi definido por CPT < 5º percentil por pletismografia. Distúrbio ventilatório obstrutivo (DVO) foi caracterizado por resistência específica de vias aéreas elevada, resposta significativa do VEF1 pós-broncodilatador e/ou um FEF25-75% < 50% do previsto associado a uma relação VR/CPT elevada. Distúrbio ventilatório inespecífico (DVI) foi caracterizado por CPT na faixa prevista e ausência de obstrução. Distúrbio ventilatório combinado (DVC) foi caracterizado por CPT reduzida e achados indicativos de obstrução ao fluxo aéreo. Os diagnósticos clínicos foram baseados em suspeita clínica, um questionário respiratório e revisão de exames de interesse.

Resultados:

Foram incluídos 300 pacientes no estudo, dos quais 108 (36%) tiveram diagnóstico de DVR, enquanto 120 (40%) foram diagnosticados com DVO ou DVC e 72 (24%) com DVI. Destes últimos, 24 (33%) tinham diagnóstico clínico de DVO. Nesta amostra, 151 pacientes (50,3%) eram obesos, e isso se associou com todos os padrões de distúrbios funcionais.

Conclusões:

Medidas dos volumes pulmonares e da resistência das vias aéreas são frequentemente necessárias para a caracterização adequada do tipo de distúrbio funcional em casos com possível restrição à espirometria. A obstrução ao fluxo aéreo é comum nesses casos.

Prevalence of airflow obstruction among ever-employed US adults aged 18-79 years by longest held occupation group: National Health and Nutrition Examination Survey 2007-2008

OBJECTIVES

To estimate the prevalence of spirometry-defined airflow obstruction among ever-employed US adults.

METHODS

Data from the 2007 to 2008 National Health and Nutrition Examination Survey (NHANES) for adults 18-79 years with valid spirometry and longest held occupation were analysed. The age-standardised prevalence of spirometry-defined airflow obstruction was estimated overall and by smoking status.

RESULTS

Age-standardised prevalence of airflow obstruction was 13.7% (95% CI 12.4% to 15.0%) and was highest in participants aged 60-79 years (17.4%, 95% CI 15.2% to 19.6%), males (14.8%, 95% CI 12.0% to 17.6%), non-Hispanic whites (15.4%, 95% CI 13.8% to 16.7%) and ever smokers (19.1%, 95% CI 16.6% to 21.5%). Age-standardised prevalence of airflow obstruction was >20% for installation, maintenance and repair occupations (p=22.1%, 95% CI 16.5% to 27.8%), and for construction and extraction occupations (20.7%, 95% CI 13.5% to 27.9%).

CONCLUSIONS

Prevalence of airflow obstruction varied by demographic characteristics and occupational factors with a higher prevalence among ever smokers for most demographic characteristics and occupational factors. Study findings emphasise the importance of monitoring the lung function of workers in occupations with a high prevalence of airflow obstruction.

Inflammation and Nutritional Science for Programs/Policies and Interpretation of Research Evidence (INSPIRE)

An increasing recognition has emerged of the complexities of the global health agenda—specifically, the collision of infections and noncommunicable diseases and the dual burden of over- and undernutrition. Of particular practical concern are both 1) the need for a better understanding of the bidirectional relations between nutritional status and the development and function of the immune and inflammatory response and 2) the specific impact of the inflammatory response on the selection, use, and interpretation of nutrient biomarkers. The goal of the Inflammation and Nutritional Science for Programs/Policies and Interpretation of Research Evidence (INSPIRE) is to provide guidance for those users represented by the global food and nutrition enterprise. These include researchers (bench and clinical), clinicians providing care/treatment, those developing and evaluating programs/interventions at scale, and those responsible for generating evidence-based policy. The INSPIRE process included convening 5 thematic working groups (WGs) charged with developing summary reports around the following issues: 1) basic overview of the interactions between nutrition, immune function, and the inflammatory response; 2) examination of the evidence regarding the impact of nutrition on immune function and inflammation; 3) evaluation of the impact of inflammation and clinical conditions (acute and chronic) on nutrition; 4) examination of existing and potential new approaches to account for the impact of inflammation on biomarker interpretation and use; and 5) the presentation of new approaches to the study of these relations. Each WG was tasked with synthesizing a summary of the evidence for each of these topics and delineating the remaining gaps in our knowledge. This review consists of a summary of the INSPIRE workshop and the WG deliberations.

Cognitive functioning in obstructive lung disease: results from the United Kingdom biobank

OBJECTIVES

To compare domains of cognitive functioning between persons with and without obstructive lung disease (OLD) and to analyze the relationship between cognitive functioning and the degree of airflow limitation.

DESIGN

An observational population-based study.

SETTING

This research was conducted using the United Kingdom Biobank Resource.

PARTICIPANTS

The study population consisted of 43,039 persons with complete data on cognitive functioning and spirometry.

MEASUREMENTS

Cognitive functioning was compared between persons with and without OLD using linear regression analysis. The relationship between impairment in lung function and cognitive impairment was assessed among persons with OLD.

RESULTS

Persons with OLD had significantly worse scores than persons without OLD on prospective memory [β = -0.15 (-0.22 to -0.09)], visuospatial memory [β round 1 = 0.06 (0.03‒0.10)]; β round 2 = 0.09 (<0.001‒0.18)), numeric short-term memory [β = ‒0.05 (‒0.10 to <0.001)] and cognitive processing speed [β = 4.62 (1.25‒8.01)] after correction for possible confounders. Impairment in prospective memory [β = 0.004 (<0.001‒0.01)] and numeric short-term memory [β = 0.01 (0.003‒0.01)] were weakly related to FEV1 (adjusted P < .05).

CONCLUSIONS

Persons with OLD experience cognitive impairment in different domains, which is partially related to airway obstruction. In particular, memory and information processing are affected. Further assessment of the relationship with patient-related outcomes is needed to optimize patient-oriented treatment.

Airway disease: similarities and differences between asthma, COPD and bronchiectasis

Airway diseases are highly prevalent worldwide; however, the prevalence of these diseases is underestimated. Although these diseases present several common characteristics, they have different clinical outcomes. The differentiation between asthma, chronic obstructive pulmonary disease and bronchiectasis in the early stage of disease is extremely important for the adoption of appropriate therapeutic measures. However, because of the high prevalence of these diseases and the common pathophysiological pathways, some patients with different diseases may present with similar symptoms. The objective of this review is to highlight the similarities and differences between these diseases in terms of the risk factors, pathophysiology, symptoms, diagnosis and treatment.

Using spirometry to rule out restriction in patients with concomitant low forced vital capacity and obstructive pattern

Background:

Different formulas have been proposed to exclude restriction based on spirometry, however none of them have specifically tested the patients whose spirometry show both obstruction and a low forced vital capacity (FVC).

Study Objective:

The study was designed to create an algorithm that would better predict the absence of restriction in such patients.

Design:

Retrospective analysis of prospectively collected data.

Methods:

A cohort of consecutive adults that underwent complete pulmonary function testing from 2002-2004 was analyzed. The data was randomly split into two groups to allow for derivation and then validation of a predictive formula. Patients were randomly assigned into either a “derivation” or “validation” group. In the derivation group, stepwise logistic regression was used to determine a formula and optimal cut-off value for the variable with the best discriminative capacity. The formula was applied subsequently to the validation group to test the results and compared to previously published formula.

Results:

The study group contained 766 patients. We determined that the variable with the highest association with TLC was [(FEV₁/FVC) % predicted/FVC % predicted]. A value of ≥1.11 was found to be the maximal cutoff to predict the absence of restriction.

The formula was applied to a validation group (n=397) and performed better than prior published algorithm with a sensitivity, specificity, positive predictive value and negative predictive value of 95%, 44%, 22%, and 98%, respectively.

Conclusion:

Our formula performs superior to the previously published algorithms in patients with concomitant low FVC and obstruction to exclude restriction.

Firing probability and mean firing rates of human muscle vasoconstrictor neurones are elevated during chronic asphyxia

Elevated muscle sympathetic nerve activity (MSNA) features in many cardiovascular diseases, but how this sympathoexcitation is brought about differs across pathologies. Unitary recordings from post-ganglionic muscle vasoconstrictor neurones in human subjects have shown that the augmented MSNA in the obstructive sleep apnoea syndrome (OSAS) is associated with an increase in firing probability and mean firing rate, and an increase in multiple within-burst firing. Here we characterize the firing properties of muscle vasoconstrictor neurones in patients with chronic obstructive pulmonary disease (COPD), who are chronically asphyxic. We tested the hypothesis that this elevated chemical drive would shift the firing pattern from that seen in healthy subjects to that seen in OSAS. The mean firing probability (52%) and mean firing rate (0.92 Hz) of 17 muscle vasoconstrictor neurones recorded in COPD were comparable to those previously recorded in OSAS (51% and 0.96 Hz), but significantly higher than those recorded in a group of healthy subjects with high levels of resting MSNA (35% and 0.33 Hz). In COPD single neurones fired once in 63% of cardiac intervals, comparable to OSAS (59%), but significantly lower than in the healthy group (78%). Conversely, single neurones fired twice in 25% of cardiac intervals, similar to OSAS (27%), but significantly higher than in the healthy group (18%). We conclude that the chronic asphyxia associated with COPD results in an increase in the firing probability and mean firing frequency of muscle vasoconstrictor neurones and causes a shift towards multiple firing, reflecting an increase in central muscle vasoconstrictor drive.

Retrospective correction for induced magnetic field inhomogeneity in measurements of large-vessel hemoglobin oxygen saturation by MR susceptometry

MR susceptometry-based blood oximetry relies on phase mapping to measure the difference in magnetic susceptibility between intravascular blood and surrounding tissue. The main source of error in MR susceptometry is the static field inhomogeneity caused by an interface between air and tissue or between adjacent tissue types. High-pass filtering has previously been used in conjunction with shimming to reduce the effect of low spatial-frequency modulations of the phase caused by large-scale induced magnetic fields. We demonstrate that high-pass filtering is not optimum for MR susceptometry because the results are sensitive to filter size. We propose an alternative method that acquires data without scanner-implemented default shimming, and fits, after appropriate weighting and masking, the static field inhomogeneity to a second-order polynomial. Compared to shimming the retrospective correction technique improved agreement between hemoglobin saturations measured in different segments of a vessel (femoral versus popliteal artery and vein) from three standard errors to less than one.

Diagnosis of interstitial lung diseases

Interstitial lung diseases (ILDs), a broad heterogeneous group of parenchymal lung disorders, can be classified into those with known and unknown causes. The definitions and diagnostic criteria for several major forms of ILDs have been revised in recent years. Although well over 100 distinct entities of ILDs are recognized, a limited number of disorders, including idiopathic pulmonary fibrosis, sarcoidosis, and connective tissue disease-related ILDs, account for most ILDs encountered clinically. In evaluating patients with suspected ILD, the clinician should confirm the presence of the disease and then try to determine its underlying cause or recognized clinicopathologic syndrome. Clues from the medical history along with the clinical context and radiologic findings provide the initial basis for prioritizing diagnostic possibilities for a patient with ILD. High-resolution computed tomography of the chest has become an invaluable tool in the diagnostic process. A confident diagnosis can sometimes be made on the basis of high-resolution computed tomography and clinical context. Serologic testing can be helpful in selected cases. Histopathologic findings procured through bronchoscopic or surgical lung biopsy are often needed in deriving a specific diagnosis. An accurate prognosis and optimal treatment strategy for patients with ILDs depend on an accurate diagnosis, one guided by recent advances in our understanding of the causes and pathogenetic mechanisms of ILDs.

Comorbidity between and risk factors for severe hearing and memory impairment in older Americans

OBJECTIVE

Comorbidities complicate our understanding of impairments and their risk factors. The objective of the current study was to assess the comorbidity between hearing impairment (HI) and memory impairment (MI) in older Americans and to assess to what extent they share common risk factors.

METHOD

Data were examined from 5252 participants aged 65 years or older from the Third National Health and Nutrition Examination Survey (1988-1994).

RESULTS

The prevalence of HI and MI was 21.4 (SE 0.8)% and 8.3 (0.6)%, respectively, but the prevalence of concurrent impairment was only 2.1 (0.2)%. African Americans had higher odds of MI than whites (OR=3.75, 95% CI: 2.81, 5.00), but not of HI (OR=0.62, 95% CI: 0.42, 0.91). Leisure physical activity was associated with lower odds of MI, good lung function was associated with lower odds of HI, and moderate alcohol use was associated with lower odds of both HI and MI. Compared with individuals free of HI, the OR of MI was 1.07 (95% CI: 0.78, 1.47) for individuals with HI.

CONCLUSION

Although prevalence was relatively high, comorbidity was surprisingly low, and the two impairments were not significantly associated. In addition to age, other factors appear to play critical but different roles in the development of these impairments.

Classification and approach to bronchiolar diseases

PURPOSE OF REVIEW

Bronchiolar abnormalities are relatively common and occur in a variety of clinical contexts. There have been an increasing number of terms, some of which are redundant, used in referring to various forms of bronchiolar disorders. The purpose of this review is to provide an updated classification scheme to facilitate the clinical approach to patients with suspected bronchiolar disease.

RECENT FINDINGS

The spectrum of bronchiolar disorders is broader and more heterogeneous than previously recognized. In deciphering the potential significance of bronchiolar abnormalities, it is useful to distinguish those disorders in which the bronchiolar involvement is the dominant pathologic process, that is, primary bronchiolar disorders, from parenchymal or large airway diseases in which the bronchioles may become secondarily involved. Primary bronchiolar disorders include respiratory bronchiolitis, acute bronchiolitis, constrictive bronchiolitis, follicular bronchiolitis, diffuse panbronchiolitis, mineral dust airway disease, and a few other variants. Interstitial lung diseases with a prominent bronchiolar involvement include smoking-related interstitial lung diseases, cryptogenic organizing pneumonia, and hypersensitivity pneumonitis. Bronchiolitis can also be seen in large airway diseases such as chronic bronchitis, bronchiectasis, and asthma.

SUMMARY

In the clinical approach to a patient with bronchiolar disease, primary bronchiolar disorders should be distinguished from predominantly parenchymal or large airway processes with bronchiolar involvement. The number of patterns of bronchiolar response to injury is limited and these patterns are generally non-specific in regard to cause. Appropriate diagnosis and management of patients with bronchiolar disorders depend on judicious correlation of clinical, physiologic, and morphologic manifestations.

Freqüência relativa de hipomagnesemia em pacientes com limitação crônica do fluxo aéreo atendidos em ambulatório de referência do norte do Paraná

OBJETIVO: Determinar a freqüência relativa de hipomagnesemia em pacientes com limitação crônica do fluxo aéreo atendidos num ambulatório de referência do norte do Paraná, nos anos de 2000 a 2001, e verificar se há relação entre esse distúrbio e hipoxemia, outros distúrbios eletrolíticos e com a gravidade da doença. MÉTODOS: Estudo descritivo sobre a freqüência relativa de hipomagnesemia em 72 pacientes com limitação crônica do fluxo aéreo. Os pacientes realizaram dosagens séricas de magnésio e outros eletrólitos, além de realizarem o estadiamento de sua doença de base. RESULTADOS: A prevalência encontrada de hipomagnesemia foi de 27,8%. A idade média foi de 65 ± 9,9 anos, com predominância de homens. O volume expiratório forçado no primeiro segundo médio foi de 1,13 ± 0,52 L. A maioria dos pacientes encontrava-se em estádios avançados da doença (68,1%). Não houve associação do magnésio sérico baixo com outros distúrbios eletrolíticos, hipoxemia ou estádios de gravidade. CONCLUSÃO: A alta freqüência de pacientes em estádios avançados deve-se, provavelmente, ao fato de o ambulatório ser um centro de referência da região. Novos estudos devem ser realizados para determinar prováveis causas dessa alta prevalência de hipomagnesemia.

Multi-dimensional phenotyping: towards a new taxonomy for airway disease

All the real knowledge which we possess, depends on methods by which we distinguish the similar from the dissimilar. The greater the number of natural distinctions this method comprehends the clearer becomes our idea of things. The more numerous the objects which employ our attention the more difficult it becomes to form such a method and the more necessary. Classification is a fundamental part of medicine. Diseases are often categorized according to pre-20th century descriptions and concepts of disease based on symptoms, signs and functional abnormalities rather than on underlying pathogenesis. Where the aetiology of disease has been revealed (for example in the infectious diseases) a more precise classification has become possible, but in the chronic inflammatory diseases, and in the inflammatory airway diseases in particular, where pathogenesis has been stubbornly difficult to elucidate, we still use broad descriptive terms such as asthma and chronic obstructive pulmonary disease, which defy precise definition because they encompass a wide spectrum of presentations and physiological and cellular abnormalities. It is our contention that these broad-brush terms have outlived their usefulness and that we should be looking to create a new taxonomy of airway disease-a taxonomy that more closely reflects the spectrum of phenotypes that are encompassed within the term airway inflammatory diseases, and that gives full recognition to late 20th and 21st century insights into the disordered physiology and cell biology that characterizes these conditions in the expectation that these will map more closely to both aetiology and response to treatment. Development of this taxonomy will require a much more complete and sophisticated correlation of the many variables that make up a condition than has been usual to employ in an approach that encompasses multi-dimensional phenotyping and uses complex statistical tools such as cluster analysis.

Asthma and COPD: differences and similarities. With special reference to the usefulness of budesonide/formoterol in a single inhaler (Symbicort) in both diseases

Asthma and chronic obstructive pulmonary disease (COPD) both have a high prevalence worldwide and yet each condition remains underdiagnosed. Despite a number of common features, these inflammatory respiratory syndromes have distinct clinical outcomes. COPD represents a greater economic burden than asthma because it has a less favourable prognosis and is associated with greater morbidity and mortality. Therefore, it is important to distinguish between these two diseases at an early stage, so that appropriate therapy can be prescribed to prevent deterioration. However, effective treatments that may be used in both conditions can minimise the effects of misdiagnosis and maximise the impact of treatment without the associated complexity when both conditions occur together. The current review summarises the differences and similarities of asthma and COPD, in terms of risk factors, pathophysiology, symptoms and diagnosis, to provide greater understanding of the role of budesonide/formoterol in a single inhaler in both diseases.

Clinical application of a simple questionnaire for the differentiation of asthma and chronic obstructive pulmonary disease

BACKGROUND

Asthma and chronic obstructive pulmonary disease (COPD) are highly prevalent chronic diseases characterized by airflow limitation. Both diseases have a distinct pathogenesis and require unique treatment approaches. Due to some common characteristic traits, asthma and COPD are often lumped together in clinical practice. We sought to develop a simple questionnaire for the distinction of asthma and COPD.

METHODS

Clinical discriminants of asthma and COPD were retrospectively identified by multiple logistic regression using files from 547 consecutive adult patients presenting to a pulmonary specialist practice with a diagnosis of asthma or COPD. With these features, we generated a simple quantitative questionnaire supporting a diagnosis of COPD with high scores and asthma with low scores (range 0-15 points). Questionnaire results were compared with physician's diagnosis based on GINA and GOLD guidelines including skin tests, spirometry and reversibility data.

RESULTS

210 patients had COPD and 337 had asthma. Age of onset, smoking history, atopy status, and cough quality were significantly associated with a diagnosis of asthma or COPD. Questionnaire scores for COPD patients were higher than those for asthmatics (mean score 10.5+/-0.18 vs. 4+/-0.12, P<0.0001). Receiver operational characteristics (ROC) analysis revealed a cutoff score of 7 with the highest discriminant power (87.6% sensitivity, 87.2% specificity for COPD, 87.4% correctly classified, area under the ROC curve: 0.954). The overlap between asthma and COPD (score 6-8) comprised about 20% of the total population, these patients included a higher proportion of COPD patients with atopy, and smoking asthmatics.

CONCLUSIONS

In patients with obstructive airway diseases, a simple questionnaire can support the differentiation of asthma and COPD in everyday clinical practice. Further prospective trials are necessary to confirm these initial observations.

Rare tracheal chondroid hamartoma masquerading as asthma in a 14-year-old girl

BACKGROUND

Tracheal hamartomas are rare in all age groups and have not been previously described in adolescence.

OBJECTIVE

To report the first case of a tracheal chondroid hamartoma presenting as exercise intolerance and wheezing and previously misdiagnosed and treated as asthma.

METHODS

Symptoms, pulmonary function tests, chest x-ray examination, chest computed tomography, and histologic examination of the specimen were performed.

RESULTS

The pulmonary function tests obtained throughout several years revealed progressive decreases (approximately 30% of predicted) in peak expiratory flow and forced expiratory volume in 1 second (approximately 50% of predicted). The inspiratory and expiratory flow-volume curve suggested a fixed central airway obstruction. Both the chest x-ray examination and computed tomography revealed an intraluminal tracheal tumor that was surgically excised. Histologic examination revealed a chondroid hamartoma.

CONCLUSIONS

Rare benign primary tracheal tumors, including chondroid hamartoma, can present in adolescence with asthma-like symptoms for years and should be considered in the differential diagnosis, especially in the setting of appropriately abnormal spirometry or when asthma is very difficult to control.

Tracheal myxoma: a rare benign tracheal tumor

Benign tracheal tumors are rare. We describe a 39-year-old man who underwent resection of a tracheal myxoma, a previously unrecognized benign tracheal neoplasm. He presented with a 9-month history of wheezing, cough, and dyspnea on exertion. Treatment with bronchodilators and corticosteroids administered by inhalation and systemically did not diminish his symptoms. Pulmonary function tests showed a pattern of airflow limitation consistent with variable extrathoracic obstruction. Chest radiography and computed tomography revealed a tracheal mass. Tracheal resection of the tumor with reconstruction was curative. The patient is free of disease 7 years after surgery.

Long-term fracture risk following adult-onset asthma: a population-based study

There are few data on skeletal outcomes in the growing population of patients with adult-onset asthma. We conducted a population-based retrospective (historical) cohort study among 226 residents of Rochester, Minnesota, USA, who were 35 years of age or older when first diagnosed with asthma. Fractures were ascertained by review of comprehensive community medical records, and observed fractures were compared with expected numbers based on incidence rates in the local population (standardized incidence ratios, SIR). During 4,022 person-years of follow-up, 100 patients experienced 211 fractures, for an actuarially estimated cumulative incidence of 63% after 30 years compared with 59% expected ( p=0.004). Statistically significant increases were seen for moderate trauma fractures of the vertebrae (SIR, 2.9; 95% CI, 2.1 to 3.8) and ribs (SIR, 2.0; 95% CI, 1.2 to 3.2), as well as the proximal femur (SIR, 1.8; 95% CI, 1.02 to 2.8). As assessed by proportional hazards models, the only independent predictors of any subsequent moderate trauma fracture were age (hazard ratio [HR] per 10-year increase, 1.7; 95% CI, 1.5 to 2.1) and cumulative corticosteroid dose greater than the median of 1,775 mg (HR, 1.8; 95% CI, 1.1 to 3.0). In another multivariate analysis, the predictors of a moderate trauma vertebral fracture were older age (HR, 1.6; 95% CI, 1.3 to 2.1), concomitant chronic obstructive pulmonary disease (HR, 2.4; 95% CI, 1.2 to 4.9), cigarette smoking (HR, 2.3; 95% CI, 1.2 to 4.8), and cumulative corticosteroid dose greater than the median (HR, 2.6; 95% CI, 1.4 to 5.0). Other asthma therapies did not contribute significantly to these models. Thus, a 70% increase in overall fracture risk among unselected community patients with adult onset asthma was mainly confined to the subset who also had chronic obstructive pulmonary disease and was influenced by substantial corticosteroid use.

Bronchiolar disorders

Bronchiolar abnormalities are relatively common and occur in a variety of clinical settings. Various histopathologic patterns of bronchiolar injury have been described and have led to confusing nomenclature with redundant and overlapping terms. Some histopathologic patterns of bronchiolar disease may be relatively unique to a specific clinical context but others are nonspecific with respect to either etiology or pathogenesis. Herein, we present a scheme separating (1) those disorders in which the bronchiolar disease is the predominant abnormality (primary bronchiolar disorders) from (2) parenchymal disorders with prominent bronchiolar involvement and (3) bronchiolar involvement in large airway diseases. Primary bronchiolar disorders include constrictive bronchiolitis (obliterative bronchiolitis, bronchiolitis obliterans), acute bronchiolitis, diffuse panbronchiolitis, respiratory bronchiolitis, mineral dust airway disease, follicular bronchiolitis, and a few other rare variants. Prominent bronchiolar involvement may be seen in several interstitial lung diseases, including hypersensitivity pneumonitis, respiratory bronchiolitis-associated interstitial lung disease, cryptogenic organizing pneumonia (idiopathic bronchiolitis obliterans organizing pneumonia), and pulmonary Langerhans' cell histiocytosis. Large airway diseases that commonly involve bronchioles include bronchiectasis, asthma, and chronic obstructive pulmonary disease. The clinical relevance of a bronchiolar lesion is best determined by identifying the underlying histopathologic pattern and assessing the correlative clinico-physiologic-radiologic context.

Undiagnosed airflow obstruction: prevalence and implications

Conditions associated with airflow obstruction are often over- and underdiagnosed. Prevalence estimates of undiagnosed airflow obstruction (UDAO) range from 3 to 12%. UDAO is a nonspecific physiologic abnormality that may be caused by a number of factors (eg, cigarette smoking) and can be the manifestation of many different disorders. The higher occurrence of UDAO among men, current or former smokers, and with advancing age provide preliminary evidence on probable causes and diagnoses (ie, chronic obstructive pulmonary disease). While cigarette smoking is associated with UDAO, a substantial proportion of persons have never smoked, particularly among women. Few studies suggest that this condition is associated with increased morbidity and mortality. While there is currently no evidence to support screening for UDAO, case-finding may have a role among persons with respiratory symptoms, who have ever smoked, with a family history of respiratory disease, or with occupational exposures to dusts or fumes.

Diagnostic approach to the patient with diffuse lung disease

Detecting diffuse lung infiltrates on chest radiography is a common clinical problem. Many diverse pathological processes can cause diffuse lung disease. The presentation of these diseases can vary from acute to chronic and includes a side array of radiological patterns that are optimally evaluated on high-resolution computed tomography of the chest. In diagnosing diffuse lung disease, it is helpful to focus on a few pivotal parameters to narrow the broad differential diagnosis. We describe the diagnostic approach to a patient with diffuse lung disease usingthe following key parameters: tempo of the pathological process, characteristics of the radiological pattern, and clinical context.

Exercise-induced bronchospasm in the elite athlete

The term exercise-induced bronchospasm (EIB) describes the acute transient airway narrowing that occurs during and most often after exercise in 10 to 50% of elite athletes, depending upon the sport examined. Although multiple factors are unquestionably involved in the EIB response, airway drying caused by a high exercise-ventilation rate is primary in most cases. The severity of this reaction reflects the allergic predisposition of the athlete, the water content of the inspired air, the type and concentration of air pollutants inspired, and the intensity (or ventilation rate) of the exercise. The highest prevalence of EIB is seen in winter-sport populations, where athletes are chronically exposed to cold dry air and/or environmental pollutants found in indoor ice arenas. When airway surface liquid lost during the natural warming and humidification process of respiration is not replenished at a rate equal to the loss, the ensuing osmolarity change stimulates the release of inflammatory mediators and results in bronchospasm; this cascade of events is exacerbated by airway inflammation and airway remodelling. The acute EIB response is characterised by airway smooth muscle contraction, membrane swelling, and/or mucus plug formation. Evidence suggests that histamine, leukotrienes and prostanoids are likely mediators for this response. Although the presence of symptoms and a basic physical examination are marginally effective, objective measures of lung function should be used for accurate and reliable diagnosis of EIB. Diagnosis should include baseline spirometry, followed by an appropriate bronchial provocation test. To date, the best test to confirm EIB may simply be standard pulmonary function testing before and after high-intensity dry air exercise. A 10% post-challenge fall in forced expiratory volume in 1 second is used as diagnostic criteria. The goal of medical intervention is to limit EIB exacerbation and allow the athlete to train and compete symptom free. This is attempted through daily controller medications such as inhaled corticosteroids or by the prophylactic use of medications before exercise. In many cases, EIB is difficult to control. These and other data suggest that EIB in the elite athlete is in contrast with classic asthma.