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Background: International guidelines recommend that pulmonary reference populations consist of never-smokers without respiratory diseases or symptoms, but the diseases and symptoms are not clearly specified. The present study aimed to identify simple exclusion criteria for defining pulmonary reference populations. Methods: Based on a random sample from a general population (the parent population), 2358 subjects aged 26-82 years performed spirometric tests. From this sample, subjects were stepwise excluded according to self-reported obstructive lung diseases, symptoms and smoking history. Four increasingly more healthy respiratory reference populations were formed. Prediction equations for the median and lower limit of normal lung function were derived using quantile regression analysis. Results: Subjects without self-reported obstructive lung diseases or the cardinal respiratory symptoms of breathlessness, cough or wheeze (population B), never-smokers without cardinal symptoms (population C) and never-smokers without any respiratory symptoms (population D) constituted 50% (n = 1184), 23% (n = 539) and 14% (n = 331) of the parent population (population A), respectively. The largest discrepancy between prediction equations was found between the parent population and the population without cardinal respiratory symptoms (population B) (p<0.5). Minor changes in the reference equations were also seen when excluding ever-smokers (population C). There was no additional change with exclusion of other respiratory symptoms (population D). Age-related decline in lung function was steepest in the parent population. Conclusions: Obstructive lung diseases, smoking history, breathlessness, cough and wheeze are optimal exclusion criteria for a pulmonary reference population. Further validation of the exclusion criteria identified in this study is recommended with identical wording in other and larger multinational populations. [ABSTRACT FROM AUTHOR]

Background: Acid reflux may aggravate airway disease including asthma and chronic cough. One postulated mechanism concerns a vagally-mediated oesophageal-tracheobronchial reflex with airway sensory nerve activation and tachykinin release. Aim: To test the hypothesis that patients with airways disease and reflux have higher airway tachykinin levels than those without reflux. Methods: Thirty-two patients with airways disease (16 with mild asthma and 16 non-asthmatic subjects with chronic cough) underwent 24 h oesophageal pH monitoring. Acid reflux was defined as increased total oesophageal acid exposure (% total time pH <4 of >4.9% at the distal probe). All subjects underwent sputum induction. Differential cell counts and concentrations of substance P (SP), neurokinin A (NKA), albumin and α2-macroglobulin were determined. Results: SP and NKA levels were significantly higher in patients with reflux than in those without (SP: 1434 (680) pg/mI vs 906(593) pg/mI, p=0.026 NKA: 81(33) pg/mI vs 52 (36) pg/mI, p=0.03). Significantly higher tachykinin levels were also found in asthmatic patients with reflux than in asthmatic patients without reflux (SP: 1508 (781) pg/mI vs 737 (512) pg/mI, p=0.035; NKA: median (interquartile range 108 (85-120) pg/mi vs 75 (2-98) pg/mI, p = 0.02). In patients with asthma there was a significant positive correlation between distal oesophageal acid exposure and SP levels (r=0.59, p=0.01) and NKA levels (r=0.56, p=0.02). Non-significant increases in SP and NKA were measured in patients with cough with reflux (SP: 1534.71 (711) pg/mI vs 1089 (606) pg/mI, p=0.20; NKA: 56 (43) pg/mI vs 49(17) pg/mI, p=0.71). No significant difference in differential cell counts or any other biochemical parameter was noted between study groups. Conclusion: This study demonstrates increased airway tachykinin levels in patients with asthma and cough patients with coexistent acid reflux. This suggests airway sensory nerve activation in this population. [ABSTRACT FROM AUTHOR]

Background: Bronchiectasis is a suppurative airway disease characterised by persistent cough and sputum production associated with bronchial dilatation. A study was undertaken to determine whether cough sensitivity is increased in bronchiectatic patients.Methods: Twenty two patients with bronchiectasis and 20 healthy non-smoking controls matched for age and sex were recruited into the study. Quality of life (Leicester Cough Questionnaire score), total cough symptom score, and extent of bronchiectasis on HRCT scans were recorded. Cough sensitivity was assessed using incremental inhalation of capsaicin concentrations; the concentration at which 5 or more coughs occurred (C5) was recorded.Results: Patients with bronchiectasis had increased sensitivity to capsaicin compared with controls (mean (SE) log10 C5 1.22 (0.20) v 1.89 (0.21); p<0.03). Capsaicin sensitivity correlated positively with the Leicester Cough Questionnaire score (r = 0.64; p = 0.005) and inversely with the total cough symptom score (r = -0.58; p = 0.004), but not with the extent of the disease. It also correlated with forced expiratory volume in 1 second (FEV1) in litres (r = 0.58; p = 0.005) but not with FEV1 % predicted. Capsaicin sensitivity was not related to the presence of infected sputum or to corticosteroid or bronchodilator use.Conclusions: : Patients with bronchiectasis have a sensitive cough reflex which reflects the severity of cough symptoms. A measure of cough severity could be part of health assessment for patients with bronchiectasis. [ABSTRACT FROM AUTHOR]

Objectives: To study motor activation patterns of voluntary and reflex cough adjusted for cough flow rates.Methods: Surface electromyography (EMG) and cough flow rate were measured in 10 healthy volunteers. Voluntary cough was assessed for 20 efforts in each quintile of increasing cough flow rate. Reflex cough was assessed for 25 efforts produced by nebulised l-tartaric acid. EMG was recorded over the expiratory (rectus abdominis, obliques, lower intercostals) and accessory (trapezius, pectoralis major, deltoid, latissimus dorsi) muscles. EMG activity, burst duration and onset were compared for each quintile of voluntary cough, and between voluntary and reflex cough matched for cough flow rate.Results: EMG activity and burst duration of expiratory and accessory muscles during voluntary cough increased in proportion to cough flow. Expiratory muscles had longer EMG burst duration (difference 68 ms (95% CI 34 to 102), p<0.01) and earlier onset of EMG activity (difference 44 ms (95% CI 20 to 68), p<0.0001) compared with accessory muscles. EMG activity in all muscles was increased (mean 110.2% v 56.1%, p<0.001) and burst duration (mean 206 ms v 280 ms, p = 0.013) decreased in reflex cough compared with voluntary cough of equal flow rate. There were no differences in EMG onset (difference 8 ms (95% CI 25 to -9) or burst duration (difference 27 ms (95% CI 58 to -4) between expiratory and accessory muscles.Conclusions: Functional organisation of motor activity differs between voluntary and reflex cough. Voluntary cough is characterised by sequential activation whereas reflex cough is associated with early and simultaneous activation of expiratory and accessory muscles. [ABSTRACT FROM AUTHOR]

Background: Quadriceps muscle weakness is common in chronic obstructive pulmonary disease (COPD) but is not observed in a small hand muscle (adductor pollicis). Although this could be explained by reduced activity in the quadriceps, the observation could also be explained by anatomical location of the muscle or fibre type composition. However, the abdominal muscles are of a similar anatomical and fibre type distribution to the quadriceps, although they remain active in COPD. Cough gastric pressure is a recently described technique that assesses abdominal muscle (and hence expiratory muscle) strength more accurately than traditional techniques. A study was undertaken to test the hypothesis that more severe weakness exists in the quadriceps than in the abdominal muscles of patients with COPD compared with healthy elderly controls.Methods: Maximum cough gastric pressure and quadriceps isometric strength were measured in 43 patients with stable COPD and 25 healthy elderly volunteers matched for anthropometric variables.Results: Despite a significant reduction in mean quadriceps strength (29.9 kg v 41.2 kg; 95% CI -17.9 to -4.6; p = 0.001), cough gastric pressure was preserved in patients with COPD (227.3 cm H(2)O v 204.8 cm H(2)O; 95% CI -5.4 to 50.6; p = 0.11).Conclusions: Abdominal muscle strength is preserved in stable COPD outpatients in the presence of quadriceps weakness. This suggests that anatomical location and fibre type cannot explain quadriceps weakness in COPD. By inference, we conclude that disuse and consequent deconditioning are important factors in the development of quadriceps muscle weakness in COPD patients, or that activity protects the abdominal muscles from possible systemic myopathic processes. [ABSTRACT FROM AUTHOR]

The article focuses on the importance of transient receptor potential vanilloid-1 (TRPV1) antagonists in the treatment of human cough through the antitussive activity of iodo-resiniferatoxin (I-RTX) in guinea pigs. Capsaicin, a well known stimulant of TRPV1, is frequently used in provocation tests to induce cough in experimental animal models and also in man. It states that TRPV1 antagonists can be predicted to be of therapeutic value not only in treatment of cough in patients with asthma and chronic obstructive pulmonary disease (COPD), but also in patients with other inflammatory disease including post viral cough and cough related to gastro-oesophageal reflux.

Background: Increased hydrogen and reduced chloride ionic environments of the airways are conducive to the stimulation of cough. However, the constituents of the local milieu of the airways of patients with chronic cough are unknown.Methods: The pH and chloride levels in exhaled breath condensate and capsaicin cough threshold (C5) were measured in 50 patients with chronic cough and in 16 healthy controls. pH and chloride measurements were repeated after capsaicin challenge in those with cough. The cause of cough was asthma (n = 13), postnasal drip/rhinitis (n = 7), gastro-oesophageal reflux (n = 5), bronchiectasis (n = 5), but remained unidentified in 20.Results: Compared with controls, patients with chronic cough had lower pH (mean 7.9 v 8.3, 95% CI of difference -0.5 to -0.2, p<0.0001), chloride levels (median 4 v 6 mmol/l, 95% CI -3.1 to -0.2, p = 0.007), and C5 (median 3.9 v 125 micro M, 95% CI -270.0 to -17.6, p = 0.002). The pH levels were different in the six subgroups including controls, and were reduced in all diagnostic subgroups of patients with cough compared with controls but did not differ between them. Chloride levels were significantly different in the six subgroups but were lower than controls in only the gastro-oesophageal reflux subgroup. There was a weak but significant correlation between chloride levels and C5 when all participants were analysed together, but not between pH and C5 or chloride levels. pH and chloride levels did not change after capsaicin challenge.Conclusions: The epithelial lining fluid of patients with chronic cough has a reduced pH and reduced chloride levels which could contribute to the enhanced cough reflex. [ABSTRACT FROM AUTHOR]

Background: There is conflicting information about the relationship between asthma and socioeconomic status, with different studies reporting no, positive, or inverse associations. Most of these studies have been cross sectional in design and have relied on subjective markers of asthma such as symptoms of wheeze. Many have been unable to control adequately for potential confounding factors.Methods: We report a prospective cohort study of approximately 1000 individuals born in Dunedin, New Zealand in 1972-3. This sample has been assessed regularly throughout childhood and into adulthood, with detailed information collected on asthma symptoms, lung function, airway responsiveness, and atopy. The prevalence of these in relation to measures of socioeconomic status were analysed with and without controls for potential confounding influences including parental history of asthma, smoking, breast feeding, and birth order using cross sectional time series models.Results: No consistent association was found between childhood or adult socioeconomic status and asthma prevalence, lung function, or airway responsiveness at any age. Having asthma made no difference to educational attainment or socioeconomic status by age 26. There were trends to increased atopy in children from higher socioeconomic status families consistent with previous reports.Conclusions: Socioeconomic status in childhood had no significant impact on the prevalence of asthma in this New Zealand born cohort. Generalisation of these results to other societies should be done with caution, but our results suggest that the previously reported associations may be due to confounding. [ABSTRACT FROM AUTHOR]

Bronchiolitis is a common condition that occurs in the first two years of life and has been associated with increased morbidity in later childhood. Following bronchiolitis, children have been noted to have increased wheeze, cough and asthma, increased airway responsiveness, and reduced lung function. When compared with other cohort members, infants with bronchiolitis will have reduced lung function and increased respiratory symptoms in childhood. This article concludes that reduced lung function is present before and after bronchiolitis; the level of reduction is comparable. The mechanism for wheeze and reduced lung function after bronchiolitis appears to be related to premorbid lung function and not bronchiolitis per se.

Background: Prospective data on the temporal relation between cough, asthma symptoms, and airway inflammation in childhood asthma is unavailable. Aims and methods: Using several clinical (diary, quality of life), lung function (FEV1, FEV1 variability, airway hyperresponsiveness), cough (diary, cough receptor sensitivity (CRS)), and inflammatory markers (sputum interleukin 8, eosinophilic cationic protein (ECP), myeloperoxidase; and serum ECP) of asthma severity, we prospectively described the course of these markers in children with asthma during a non-acute, acute, and resolution phase. A total of 21 children with asthma underwent these baseline tests; 11 were retested during days 1, 3, 7, and 28 of an exacerbation. Results: Asthma exacerbations were characterised by increased asthma and cough symptoms and eosinophilic inflammation. Sputum ECP showed the largest increase and peaked later than clinical scores. Asthma scores consistently related to cough score only early in the exacerbation. Neither CRS nor cough scores related to any inflammatory marker. Conclusion: In mild asthma exacerbations, eosinophilic inflammation is dominant. In asthmatic children who cough as a dominant symptom, cough heralds the onset of an exacerbation and increased eosinophilic inflammation, but cough scores and CRS do not reflect eosinophilic airway inflammation. [ABSTRACT FROM AUTHOR]

Background: It has been suggested that cough effectiveness can be improved by assisted techniques. The effects of manually assisted cough and mechanical insufflation on cough flow physiology are reported in this study.Methods: The physiological actions and patient self-assessment of manually assisted cough and mechanical insufflation were investigated in 29 subjects (nine normal subjects, eight patients with chronic obstructive pulmonary disease (COPD), four subjects with respiratory muscle weakness (RMW) with scoliosis, and eight subjects with RMW without scoliosis).Results: The peak cough expiratory flow rate and cough expiratory volume were not improved by manually assisted cough and mechanical insufflation alone or in combination in normal subjects. The median increase in peak cough expiratory flow in subjects with RMW without scoliosis with manually assisted cough alone or in combination with mechanical insufflation of 84 l/min (95% confidence interval (CI) 19 to 122) and 144 l/min (95% CI 14 to 195), respectively, reflects improvement in the expulsive phase of coughing by these techniques. Manually assisted cough and mechanical insufflation in combination raised peak expiratory flow rate more than either technique alone in this group. The abnormal chest shape in scoliotic subjects and the fixed inspiratory pressure used made effective manually assisted cough and mechanical insufflation difficult in this group and no improvements were found. In patients with COPD manually assisted cough alone and in combination with mechanical insufflation decreased peak expiratory flow rate by 144 l/min (95% CI 25 to 259) and 135 l/min (95% CI 30 to 312), respectively.Conclusions: Manually assisted cough and mechanical insufflation should be considered to assist expectoration of secretions in patients with RMW without scoliosis but not in those with scoliosis. [ABSTRACT FROM AUTHOR]

Baker's asthma remains one of the most important causes of occupational asthma. In a Polish study it has been suggested that attacks of coughing at work may precede the development of baker's asthma by several years. Exposure to grain dust is sustained from harvesting, storage and processing of wheat, oat, barley, maize or rye. Respiratory disease caused by grain dust ma be caused immunological responses directed towards groin or a response from other co-existing substances within grain dust. The clinical history is the cornerstone of patient assessment as it directs investigations, diagnosis and management. Occupational asthma is notoriously difficult to diagnose on history alone.

Eosinophilic bronchitis is an important cause of chronic cough. It is characterised by eosinophilic airway inflammation in the absence of airway hyperresponsiveness or other markers of variable airflow obstruction. Treatment with inhaled corticosteroids is associated with a short term improvement in cough and reduced sputum eosinophil count but the longer term outcome is uncertain. Reflux cough is a diagnosis based on the demonstration of gastroesophageal reflux on 24 hour oesophageal pH monitoring (OpHM) and a positive response to anti-reflux therapy. The aim of the study was to determine both the early and long term response to anti-reflux therapy in those with a "positive" pH study, and identily any features on OpHM which could accurately predict response therapy.

The article focuses on a research on the diagnosis of a rare case of children cough, primary ciliary dyskinesia (PCD). The article concludes that if the diagnosis of PCD is to be made and morbidity avoided, a clear, focused history and examination is required to select the child who needs specialist referral. At the moment, too many children with PCD are not being diagnosed early enough, and thus treated appropriately.

This article presents various studies related to cough. Chronic cough is an inflammatory condition of the airways and inhaled steroids are often used empirically as a therapeutic trial. The aim of this study was to determine if non-invasive tests of airway inflammation, such as induced sputum cell counts, exhaled nitric oxide (NO) and exhaled carbon monoxide as well as nasal NO can predict a successful response to inhaled steroid treatment. Cough is commonly associated with symptoms of asthma. However, there is conflicting evidence as to whether cough and bronchoconstriction are directly related.

The article presents a study which investigates the association between men and women with chronic obstructive pulmonary disease (COPD) and urinary incontinence (UI) with poorer quality of life. A descriptive survey design was used to determine the impact of cough and UI on the quality of life among 391 women and 337 men with COPD. Results indicate that women who had UI had a significant higher burden of symptoms than compared to men who had higher prevalence of cough and phlegm production.

The article offers news briefs related to pulmonary diseases as of August 2015. The highest number of cases of whooping cough in the U.S. since 1955 has been reported in 2012. A new drug called Idebenone has been introduced for treating duchenne's muscular dystrophy. A study conducted in Great Britain has revealed that distance to hospital influences patients with chronic obstructive pulmonary disease (COPD).

The article offers a short review relating to chronic cough in children. The section discusses the effects of a seminal paper by Sheila Mackenzie from the early 1990s on the author's approach to the diagnosis and management of chronic cough in children. The author states that Mackenzie's review was not that cough variant asthma does not exist, because the axiom remains that it is unwise to use never in medicine and that the author have a very small number of patients who fits the label.