An observational study to determine the relationship between cough frequency and markers of inflammation in severe asthma

BACKGROUND

The relationship between objectively measured cough and type 2 (T2) biomarkers and other measures of asthma control and severity is poorly understood. The objective of this study was to assess the relationship between objective and subjective cough measurement tools and clinical biomarkers of asthma.

METHODS

Patients with severe asthma and mild-to-moderate asthma completed validated asthma and cough-related measurement tools (including ambulatory cough monitoring) and measurement of spirometry and T2 biomarkers (exhaled nitric oxide fraction (F ENO) and peripheral blood eosinophil count). Patients were classified according to T2 status based on T2-low (F ENO <20 ppb and peripheral blood eosinophils <150 cells·µL-1), T2-intermediate (F ENO ≥20 ppb or peripheral blood eosinophils ≥150 cells·µL-1) or T2-high (F ENO ≥20 ppb and peripheral blood eosinophils ≥150 cells·µL-1).

RESULTS

61 patients completed the study measurements (42 severe asthma and 19 mild-to-moderate asthma). Patients with severe asthma had higher rates of cough than those with mild-to-moderate asthma in terms of total 24-h cough counts (geometric mean±sd 170.3±2.7 versus 60.8±4.1; p=0.002) and cough frequency (geometric mean±sd 7.1±2.7 versus 2.5±4.1 coughs·h-1; p=0.002). T2-low patients with severe asthma had significantly lower 24-h cough frequency compared with T2-intermediate and T2-high patients.

CONCLUSIONS

In patients with low biomarkers of T2 inflammation, cough frequency measurements were not elevated, suggesting that the mechanism for cough in asthma is underlying T2 eosinophilic inflammation and the logical first step for treating cough in asthma may be to achieve adequate suppression of T2 inflammation with currently available therapies.

Objective and Subjective Measurement of Cough in Asthma: A Systematic Review of the Literature

Background

The extent to which objective and subjective tools has been used to measure the characteristics and burden of cough in patients with asthma has not been reported.

Objective

To review the large and extensive body of literature in asthma with the specific hypothesis that the characteristics of cough and clinical impact in this disease has only occasionally been studied.

Methods

For this systematic review, we searched EMBASE and MEDLINE databases using a combination of MeSH terms for “cough” and “asthma” for studies published up to and including end of August 2021. Studies included for analysis were confined to those undertaken in adult patients (≥ 18 years) with asthma of any severity where any tool or method to specifically measure cough was employed.

Results

Of 12,090 citations identified after our initial search, 112 full-text articles met criteria for inclusion in our analysis. We found that a broad range of objective and subjective measures have been used albeit with a lack of consistency between studies. Clinically important levels of cough associated with impaired health status were identified in patients with asthma.

Conclusion

Although cough is a common symptom in asthma, the clinical features and accompanying healthcare burden have been studied infrequently. In studies where cough was measured, the methods employed varied considerably. A more consistent use of cough-specific measurement tools is required to better determine the nature and burden of cough in asthma.

Glucocorticoid toxicity reduction with mepolizumab using the Glucocorticoid Toxicity Index

BACKGROUND

Reduction in glucocorticoid exposure is the primary benefit of new biologic treatments in severe asthma, but there is currently no evidence that reduction in glucocorticoid exposure corresponds to a proportionate reduction in associated toxicity.

OBJECTIVES

To use the validated Glucocorticoid Toxicity Index (GTI) to assess change in glucocorticoid toxicity after 12 months treatment with mepolizumab, and compare toxicity change to glucocorticoid reduction and change in patient-reported outcome measures (PROMs).

METHODS

A longitudinal, real-world prospective cohort of 101 consecutive patients with severe asthma commenced on mepolizumab in a specialist UK regional severe asthma clinic. GTI toxicity assessment, cumulative glucocorticoid exposure and PROMs were recorded on commencing mepolizumab (V1), and after 12 months treatment (V2).

RESULTS

There was significant reduction in oral glucocorticoid exposure (V1 median 4280 mg prednisolone per year (interquartile range 3083-5475 mg) versus V2 2450 mg prednisolone per year (1243-3360 mg), p<0.001). Substantial improvements in individual toxicities were observed, but did not correlate with oral glucocorticoid reduction. Mean±sd GTI aggregate improvement score (AIS) was -35.7±57.8 with a wide range in toxicity change at individual patient level (AIS range -165 to +130); 70% (71 out of 101) had a reduction in toxicity (AIS <0); 3% (three out of 101) had no change (AIS=0); and 27% (27 out of 101) an increase in overall toxicity. 62% (62 out of 101) of patients met the AIS minimally clinically important difference of ≤-10, but AIS did not correlate with glucocorticoid reduction or change in PROMs.

CONCLUSION

Mepolizumab resulted in substantial oral glucocorticoid reduction, but this did not correlate with reduction in oral glucocorticoid toxicity, which varies widely at the individual patient level. Oral glucocorticoid reduction is not a comprehensive measure of response to mepolizumab.

Quantification of Glucocorticoid-Associated Morbidity in Severe Asthma Using the Glucocorticoid Toxicity Index

BACKGROUND

Glucocorticoid (GC)-associated morbidity in severe asthma (SA) is well recognized but varies in individual patients; systematic measurement of GC toxicity is important to measure improvement with steroid-sparing monoclonal antibodies.

OBJECTIVE

To describe for the first time individual patient GC toxicity in steroid-dependent SA using the Glucocorticoid Toxicity Index (GTI).

METHODS

An observational consecutive patient cohort study was performed at a UK Regional SA Specialist clinic for systematic assessment of GC-associated morbidity using the GTI in routine clinical care. GTI was correlated with commonly used patient-reported outcome measures. An approach to GTI scoring, calculation of minimal clinically important difference (MCID), and development of digital GTI application in routine clinical care are described.

RESULTS

All patients had significant oral GC exposure (cumulative prednisolone/prior year, 4280 [3083, 5475] mg) with wide distribution of toxicity in individual patients (mean GTI score, 177.5 [73.7]). GTI score had only modest correlation with recent prednisolone exposure: maintenance prednisolone dose (rho = 0.26, P = .01), cumulative exposure/prior year (rho = 0.38, P < .001), and GC boosts/prior year (rho = 0.25, P = .01). GTI toxicity demonstrated stronger associations with asthma-related quality of life (mini-Asthma Quality of Life Questionnaire [mini-AQLQ] r = -0.50, P < .001 and St. George's Respiratory Questionnaire r = 0.42, P < .001). GTI MCID was calculated as 10 points. Multiple linear regression demonstrated that age and mini-AQLQ were strongest predictors of GC toxicity.

CONCLUSIONS

The GTI is a useful tool to systematically capture and quantify GC toxicity at the individual patient level. GC toxicity varies widely between individual patients with SA and correlated only modestly with GC exposure over the preceding year. Age and mini-AQLQ are better predictors of GC toxicity. The GTI and MCID will facilitate assessment of individual SA response to steroid-sparing agents in clinical trials and routine care.

Respiratory virus infection up-regulates TRPV1, TRPA1 and ASICS3 receptors on airway cells

Receptors implicated in cough hypersensitivity are transient receptor potential vanilloid 1 (TRPV1), transient receptor potential cation channel, Subfamily A, Member 1 (TRPA1) and acid sensing ion channel receptor 3 (ASIC3). Respiratory viruses, such as respiratory syncytial virus (RSV) and measles virus (MV) may interact directly and/or indirectly with these receptors on sensory nerves and epithelial cells in the airways. We used in vitro models of sensory neurones (SHSY5Y or differentiated IMR-32 cells) and human bronchial epithelium (BEAS-2B cells) as well as primary human bronchial epithelial cells (PBEC) to study the effect of MV and RSV infection on receptor expression.

Receptor mRNA and protein levels were examined by qPCR and flow cytometry, respectively, following infection or treatment with UV inactivated virus, virus-induced soluble factors or pelleted virus. Concentrations of a range of cytokines in resultant BEAS-2B and PBEC supernatants were determined by ELISA.

Up-regulation of TRPV1, TRPA1 and ASICS3 expression occurred by 12 hours post-infection in each cell type. This was independent of replicating virus, within the same cell, as virus-induced soluble factors alone were sufficient to increase channel expression. IL-8 and IL-6 increased in infected cell supernatants. Antibodies against these factors inhibited TRP receptor up-regulation. Capsazepine treatment inhibited virus induced up-regulation of TRPV1 indicating that these receptors are targets for treating virus-induced cough.

Personalised Medicine for Asthma and Chronic Obstructive Pulmonary Disease

Asthma and chronic obstructive pulmonary disease (COPD) are prevalent conditions, and despite recent advances and multiple available therapies and interventions, there remains a significant unmet clinical need. In recent years, it has become clear that there is both significant heterogeneity within each of these conditions and additionally significant overlap in many of the clinical and inflammatory features. In parallel, useful clinical and immunological biomarkers which inform about prognosis and response to therapy have emerged in both asthma and COPD. These biomarkers will allow both better targeting of existing treatments and the identification of those patients who will respond to novel therapies which are now becoming available. Biomarkers will also facilitate the identification of novel therapeutic targets for future development. Delivery of precision medicine in airways disease is now feasible and is a core component of a personalised healthcare delivery in asthma and COPD.

Rhinovirus upregulates transient receptor potential channels in a human neuronal cell line: implications for respiratory virus-induced cough reflex sensitivity

BACKGROUND

The mechanism underlying respiratory virus-induced cough hypersensitivity is unknown. Upregulation of airway neuronal receptors responsible for sensing physical and chemical stimuli is one possibility, and the transient receptor potential (TRP) channel family are potential candidates. We have used an in vitro model of sensory neurons and human rhinovirus (HRV-16) to study the effect of virus infection on TRP expression.

METHODS

IMR-32 neuroblastoma cells were differentiated in culture to express three TRP channels: TRPV1, TRPA1 and TRPM8. Flow cytometry and qRT-PCR were used to measure TRP channel protein and mRNA levels following inoculation with live virus, inactivated virus, virus-induced soluble factors or pelleted virus particles. Multiplex bioassay was used to determine nerve growth factor (NGF), interleukin (IL)-1β, IL-6 and IL-8 levels in response to infection.

RESULTS

Early upregulation of TRPA1 and TRPV1 expression occurred 2-4 h post infection. This was independent of replicating virus as virus-induced soluble factors alone were sufficient to increase channel expression 50-fold and 15-fold, respectively. NGF, IL-6 and IL-8 levels, increased in infected cell supernatants, represent possible candidates. In contrast, TRPM8 expression was maximal at 48 h (9.6-fold) and required virus replication rather than soluble factors.

CONCLUSIONS

We show for the first time that rhinovirus can infect neuronal cells. Furthermore, infection causes upregulation of TRP channels by channel-specific mechanisms. The increase in TRPA1 and TRPV1 levels can be mediated by soluble factors induced by infection whereas TRPM8 requires replicating virus. TRP channels may be novel therapeutic targets for controlling virus-induced cough.

Impaired lung function and health status in adult survivors of bronchopulmonary dysplasia

More infants with bronchopulmonary dysplasia (BPD) now survive to adulthood, but little is known regarding persisting respiratory impairment. We report respiratory symptoms, lung function and health-related quality of life (HRQoL) in adult BPD survivors compared with preterm (non-BPD) and full-term controls. Respiratory symptoms (European Community Respiratory Health Survey) and HRQoL (EuroQol (EQ)-5D) were measured in 72 adult BPD survivors (mean ± sd study age 24.1 ± 4.0 years; mean ± sd gestational age 27.1 ± 2.1 weeks; and mean ± sd birth weight 955 ± 256 g) cared for in the regional neonatal intensive care unit, Royal Maternity Hospital, Belfast, UK (between 1978 and 1993). These were compared with 57 non-BPD controls (mean ± sd study age 25.3 ± 4.0 years; mean ± sd gestational age 31.0 ± 2.5 weeks; and mean ± sd birth weight 1238 ± 222 g) and 78 full-term controls (mean ± sd study age 25.7 ± 3.8 years; mean ± sd gestational age 39.7 ± 1.4 weeks; and mean ± sd birth weight 3514 ± 456 g) cared for at the same hospital. Spirometry was performed on 56 BPD, 40 non-BPD and 55 full-term participants. BPD subjects were twice as likely to report wheeze and three times more likely to use asthma medication than controls. BPD adults had significantly lower forced expiratory volume in 1 s and forced expiratory flow at 25-75% of forced vital capacity than both the preterm non-BPD and full-term controls (all p<0.01). Mean EQ-5D was 6 points lower in BPD adults compared to full-term controls (p<0.05). BPD survivors have significant respiratory and quality of life impairment persisting into adulthood.

General and respiratory health outcomes in adult survivors of bronchopulmonary dysplasia: a systematic review

BACKGROUND

The purpose of this systematic literature review was to examine current empirical research on general and respiratory health outcomes in adult survivors of bronchopulmonary dysplasia (BPD).

METHODS

We searched seven databases up to the end of November 2010 (MEDLINE, PubMed, EMBASE, PsycINFO, Maternity and Infant Care, Cumulative Index of Nursing and Allied Health Literature, and Web of Knowledge). We independently screened and included only those studies concerning the assessment of outcome measures in adult survivors of BPD. Data on methodologic design and findings were extracted from each included study; in addition, the methodologic quality of each study was assessed using the Critical Appraisal Skills Programme checklist.

RESULTS

Fourteen cohort studies met the review criteria. Of those, a total of eight studies were considered to be of high quality (score 9-12), five of moderate quality (score 5-8), and only one was of low quality (score 0-4). In all studies of adult survivors of BPD, differences were found between the index and control groups, suggesting that many adults survivors of BPD who were born preterm or with very low birth weight had more respiratory symptoms and pulmonary function abnormalities compared with their peers. Five studies concerning radiologic findings reported structural changes persisting into adulthood. Findings from three studies suggested impairment in exercise capacity, although firm conclusions were limited by the small sample size in the studies reviewed.

CONCLUSIONS

Compared with adults born at term, adult survivors of BPD have more impairment in general and respiratory health, which does not seem to diminish over time.

Respiratory and laryngeal symptoms secondary to gastro-oesophageal reflux

Gastro-oesophageal reflux may cause a range of laryngeal and respiratory symptoms. Mechanisms responsible include the proximal migration of gastric refluxate beyond the upper oesophageal sphincter causing direct irritation of the larynx and lower airway. Alternatively, refluxate entering the distal oesophagus alone may stimulate oesophageal sensory nerves and indirectly activate airway reflexes such as cough and bronchospasm. Recognising reflux as a cause for these extraoesophageal symptoms can be difficult as many patients do not have typical oesophageal symptoms (eg, heartburn) and clinical findings on laryngoscopy are not very specific. Acid suppression remains an effective treatment in the majority of patients but there is growing appreciation of the need to consider and treat non-acid and volume reflux. New opinions about the role of existing medical and surgical (laparoscopic techniques) treatment are emerging and a number of novel anti-reflux treatments are under development.

Future directions in treating cough

Cough is a common and troublesome symptom that can be difficult to treat. New therapeutic options that are safe and more effective than those currently available are needed. In this article, the authors offer opinion on future directions in the treatment of cough, with a particular emphasis on the clinical syndrome associated with cough reflex hypersensitivity. In addition, the article provides an overview of some of the diagnostic technologies and promising drug targets likely to emerge from current clinical and scientific endeavor.

Common causes and current guidelines

Chronic cough is a common and disabling symptom. Recent guidelines have attempted to provide direction in the clinical management of cough in both primary and secondary care. They have also provided a critical review of the available literature and identified gaps in current knowledge. Despite this they have been criticized for a reliance on a low quality evidence base. In this review, we summarize the current consensus on the clinical management of chronic cough and attempt to rationalize this based on recent evidence. We have also provided an overview of the likely pathophysiological mechanisms responsible for cough and highlighted areas, where knowledge deficits exist and suggest directions for future research. Such progress will be critical in the search for new and effective treatments for cough.

Calcitonin gene-related peptide relates to cough sensitivity in children with chronic cough

Airway neuropeptides, in particular calcitonin gene-related peptide (CGRP), are likely to be important in the pathogenesis of chronic cough. The present authors evaluated the following: 1) the relationship between cough sensitivity and bronchoalveolar lavage (BAL) neuropeptides; and 2) the effect of reflux oesophagitis (RO) on cough, cough sensitivity and BAL neuropeptides in children not selected for cough. It was hypothesised that CGRP would be increased in children with chronic cough and would relate to cough sensitivity. Capsaicin cough sensitivity was performed in children undergoing gastro-duodenal endoscopy. CGRP, substance P and neurokinin A were measured in BAL obtained nonbronchoscopically. Children were defined as "coughers" if chronic cough was present. Coughers (n = 21) had significantly reduced cough sensitivity but were just as likely as noncoughers (n = 19) to have RO. The median CGRP was significantly higher in coughers with oesophagitis than in noncoughers with oesophagitis. CGRP significantly negatively correlated to cough sensitivity in coughers but not in noncoughers. Elevated calcitonin gene-related peptide, but not substance P or neurokinin A, is only associated with chronic cough in children when oesophagitis coexists. Calcitonin gene-related peptide in bronchoalveolar lavage relates to cough sensitivity and is likely to be important in the pathophysiology of chronic cough.

Increased tachykinin levels in induced sputum from asthmatic and cough patients with acid reflux

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 alpha2-macroglobulin were determined.

RESULTS

SP and NKA levels were significantly higher in patients with reflux than in those without (SP: 1434 (680) pg/ml vs 906 (593) pg/ml, p=0.026; NKA: 81 (33) pg/ml vs 52 (36) pg/ml, 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/ml vs 737 (512) pg/ml, p=0.035; NKA: median (interquartile range 108 (85-120) pg/ml vs 75 (2-98) pg/ml, 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/ml vs 1089 (606) pg/ml, p=0.20; NKA: 56 (43) pg/ml vs 49 (17) pg/ml, 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.

Clinical cough and its mechanisms

Cough is the commonest symptom of clinical importance and the most frequent reason for new consultations with a doctor. Although therapy directed at any underlying cause for cough can be effective there is a clinical need for new treatments specifically directed at the cough itself. A major obstacle to the development of such therapy has been an imprecise understanding of the pathophysiological mechanisms responsible for cough. In this article, we review the important clinical aspects of both acute and chronic cough, offer practical insight into the existing treatment options, highlight the current understanding of cough pathophysiology and identify important areas for future research effort.

Idiopathic chronic cough: a real disease or a failure of diagnosis?

Despite extensive diagnostic evaluation and numerous treatment trials, a number of patients remain troubled by a chronic and uncontrollable cough. Eosinophilic bronchitis, atopic cough and non-acid reflux have been recently added to the diagnostic spectrum for chronic cough. In some cases, failure to consider these conditions may explain treatment failure. However, a subset of patients with persisting symptoms may be regarded as having an idiopathic cough. These individuals are most commonly female, of postmenopausal age and frequently report viral upper respiratory tract infections as an initiating event. This paper seeks to explore the validity of idiopathic cough as a distinct clinical entity.

Patients with gastro-oesophageal reflux disease and cough have impaired laryngopharyngeal mechanosensitivity

BACKGROUND

Laryngopharyngeal sensitivity (LPS) is important in preventing pulmonary aspiration and may be impaired by anaesthesia and stroke. It has been suggested that gastro-oesophageal reflux disease (GORD) may also impair LPS, although the underlying mechanism is unclear. The aim of this study was to compare LPS in patients with chronic cough and GORD with healthy subjects and to determine the effect of laryngopharyngeal infusions of both acid and normal saline on LPS.

METHODS

Fifteen patients with chronic cough and GORD and 10 healthy subjects without GORD underwent LPS testing using the fibreoptic endoscopic evaluation of swallowing with sensory testing (FEESST) technique. LPS, as measured by the lowest air pressure required to elicit the laryngeal adductor reflex (LAR), was determined both before and after laryngopharyngeal infusions of normal saline and 0.1 N hydrochloric acid performed on separate days.

RESULTS

The mean baseline LAR threshold of the patient group was significantly higher (9.5 mm Hg, range 6.0-10.0) than in normal subjects (3.68 mm Hg, range 2.5-5.0; p<0.01). Retest thresholds were not significantly different. In normal subjects LAR thresholds were significantly raised after acid but not after saline infusion (p = 0.005). There were no complications associated with the procedure.

CONCLUSIONS

Patients with cough and GORD have significantly reduced LPS to air stimuli compared with healthy subjects which could potentially result in an increased risk of aspiration. Exposure to small amounts of acid significantly impaired the sensory integrity of the laryngopharynx.

Acute and chronic cough

Individuals are generally content to self-medicate for acute cough. It is only when the cough becomes persistent that they seek medical assistance. It is not known why patients cough in association with an acute upper respiratory tract infection (URTI), although interest has focused on how viruses may influence airway sensory nerve function and contribute to heightened cough reflex sensitivity. Why some patients develop a persistent cough following a viral URTI is also unclear. Much more is known about the causes and aggravants of chronic cough although there is no broad agreement as to the best way to manage such patients. Asthma, upper gastrointestinal dysfunction and rhinitis are frequently associated with chronic cough, although the impact of cough in suppurative lung disease and interstitial lung fibrosis is rarely considered. The development of effective treatments for cough remains a challenge and will require co-operation between clinicians, scientists and the pharmaceutical industry.

Oesophageal pH monitoring is of limited value in the diagnosis of "reflux-cough"

Reflux-cough is a diagnosis based on demonstrating both gastro-oesophageal reflux and a positive response to anti-reflux therapy. The authors sought to determine early and long-term response to therapy in patients with a "positive" 24 h oesophageal pH study, and identify any features which might predict response. Patients with chronic cough were recruited from July 1998 to July 2002. Those with a positive pH study were given dietary advice and an 8-week trial of omeprazole (20 mg b.i.d.). Response was judged after 8 weeks (clinical follow-up), and at long-term follow-up (telephone questionnaire). A total of 146 patients underwent pH monitoring with 82 (56.2%) "positive" studies. Follow-up data was available in 60 patients, with 49 receiving anti-reflux therapy, of which 20 (40.8%) reported a positive treatment response. At long-term follow-up (median 30 months), there was a significantly lower response (14 out of 49, 28.5%), with no significant difference in either acid exposure times (distal/proximal) or symptom correlation between responders and nonresponders at early or long-term follow-up. In conclusion, despite "positive" pH studies, over half of the patients (55.1%) failed to respond to therapy. No features on pH monitoring accurately predicted response. Short-term response did not predict long-term response. The precise role for pH monitoring in the assessment of chronic cough remains to be defined.

Idiopathic cough, prevalence and underlying mechanisms

A number of authors have reported a significant percentage of patients whose cause of cough remains undetermined despite a systematic evaluation as recommended in a number of International Guidelines. This subset of patients, which may be regarded as having an idiopathic cough, are often female and of peri or postmenopausal age. Sex hormones may influence the cough reflex in disease or contribute to the chronic lymphocytic airway inflammation seen in some cases and to the association with organ specific autoimmune disease reported. This paper seeks to investigate some of the possible causes of idiopathic cough.

Cytokine concentrations and neutrophil elastase activity in bronchoalveolar lavage and induced sputum from patients with cystic fibrosis, mild asthma and healthy volunteers

BACKGROUND

Induced sputum (IS) has been proposed as a non-invasive alternative to bronchoalveolar lavage (BAL) for the assessment and monitoring of airways inflammation. The aim of this study was to compare both methods in patients with cystic fibrosis (CF). The possible differences between subjects with CF, mild asthma and healthy volunteers (HV) was also assessed.

METHOD

In a single centre, randomised, two way crossover study, 11 patients with CF, 9 mild asthmatics (MA) and 11 HV underwent BAL and hypertonic saline induction on consecutive days. Free neutrophil elastase (NE), neutrophil elastase/alpha(1)-anti-trypsin complex (NE-AAT), tumour necrosis factor receptor (p55) and interleukin-8 (IL-8) were measured in cell free supernatants.

RESULTS

Three CF patients reported serious adverse events following BAL. NE was usually undetectable in both IS or BAL samples and NE-AAT concentrations did not differ consistently between the two sampling methods. IL-8 and p55 levels in the CF patients tended to be higher in IS samples compared with BAL samples (median 19,860 vs. 3,855 pg/ml and 2.55 vs. 0.29 ng/ml, respectively). There was a significant difference in mean p55 concentrations between CF, MA and HV in IS samples (P=0.003) but not in BAL samples (P=0.36). The difference in mean IL-8 concentrations in IS samples between subject groups was statistically different (P=0.023).

CONCLUSIONS

IS samples can be safely obtained from CF patients. Analysis of IS samples can help to characterize the inflammatory process in the airways of CF patients. The serious adverse events following BAL in 3 CF patients highlight an inherent risk associated with this procedure.

Cough . 6: Which investigations are most useful in the diagnosis of chronic cough?

There is no consensus as to the best diagnostic strategy for chronic cough. Many protocols combine empirical trials of treatment with laboratory investigations. More precise diagnostic tools and improved therapeutic options are required. Until then, the management of chronic cough will remain a clinical challenge.

Psychogenic cough in a schoolboy: evaluation using an ambulatory cough recorder

Psychogenic cough occurs most commonly in patients under 18 years of age. Making the diagnosis on clinical features alone is problematic, and it is usually a diagnosis of exclusion after several negative clinical investigations. We report on the case of a 13-year-old schoolboy with a 3-month history of persistent dry cough with no other associated symptoms. Clinical examination and investigations revealed no abnormality, and empirical trials of antiasthma and antacid medications proved unsuccessful. An objective assessment of his cough frequency was made using an ambulatory cough monitor. A large number of cough episodes were recorded during the day, but during the time he was in bed there were very few episodes recorded. This suggested a diagnosis of psychogenic cough, and he underwent behavior modification therapy under the guidance of a clinical psychologist, with good result. Objective cough monitoring may therefore improve the evaluation and management of chronic cough.

Pseudodextrocardia in bronchiectasis

Bronchiectasis is a chronic inflammatory pulmonary disorder characterized by chronic productive cough, recurrent bronchial sepsis and haemoptysis, with airflow obstruction and progressive tissue destruction. Kartagener's syndrome, associated with dysfunctional cilia, sinusitis and situs inversus, is a rare cause of bronchiectasis (Marwah and Sharman, 1995). This article reports two cases where patients had been erroneously diagnosed as having Kartagener's syndrome based on misinterpretations of chest radiographs.