Cough, airway inflammation, and mild asthma exacerbation

A smartphone-based application for cough counting in patients with acute asthma exacerbation

BACKGROUND

While tools exist for objective cough counting in clinical studies, there is no available tool for objective cough measurement in clinical practice. An artificial intelligence (AI)-based cough count system was recently developed that quantifies cough sounds collected through a smartphone application. In this prospective study, this AI-based cough algorithm was applied among real-world patients with an acute exacerbation of asthma.

METHODS

Patients with an acute asthma exacerbation recorded their cough sounds for 7 days (2 consecutive hours during awake time and 5 consecutive hours during sleep) using CoughyTM smartphone application. During the study period, subjects received systemic corticosteroids and bronchodilator to control asthma. Coughs collected by application were counted by both the AI algorithm and two human experts. Subjects also provided self-measured peak expiratory flow rate (PEFR) and completed other outcome assessments [e.g., cough symptom visual analogue scale (CS-VAS), awake frequency, salbutamol use] to investigate the correlation between cough and other parameters.

RESULTS

A total of 1,417.6 h of cough recordings were obtained from 24 asthmatics (median age =39 years). Cough counts by AI were strongly correlated with manual cough counts during sleep time (rho =0.908, P<0.001) and awake time (rho =0.847, P<0.001). Sleep time cough counts were moderately to strongly correlated with CS-VAS (rho =0.339, P<0.001), the frequency of waking up (rho =0.462, P<0.001), and salbutamol use at night (rho =0.243, P<0.001). Weak-to-moderate correlations were found between awake time cough counts and CS-VAS (rho =0.313, P<0.001), the degree of activity limitation (rho =0.169, P=0.005), and salbutamol use at awake time (rho =0.276, P<0.001). Neither awake time nor sleep time cough counts were significantly correlated with PEFR.

CONCLUSIONS

The strong correlation between cough counts using the AI-based algorithm and human experts, and other indicators of patient health status provides evidence of the validity of this AI algorithm for use in asthma patients experiencing an acute exacerbation. Study findings suggest that CoughyTM could be a novel solution for objectively monitoring cough in a clinical setting.

Cough Hypersensitivity Syndrome: Why Its Use Is Inappropriate in Children

In children and adults, chronic cough is a common symptom presenting to health professionals worldwide. It is internationally accepted that children with chronic cough should be managed with pediatric specific management guidelines. The newly proposed clinical entity of 'cough hypersensitivity syndrome' has gained significant attention in adult literature. Given the significant differences between childhood and adult chronic cough, including in respiratory physiology and anatomy, and cough sensitivity, we address the suitability of the use of cough hypersensitivity syndrome in children. We explore these differences between childhood and adult chronic cough, explain what cough hypersensitivity is and highlight why the term cough hypersensitivity syndrome should not be used in children.

Stability of sputum inflammatory phenotypes in childhood asthma during stable and exacerbation phases

BACKGROUND

Management strategies based on airway inflammation phenotypes are increasingly used for adults with asthma. While sputum-based phenotypes are relatively stable in adults with asthma, there is little such data in childhood asthma. Hence, we aimed to evaluate the stability of sputum inflammatory phenotypes in children with asthma both in the stable and during exacerbation phases.

METHODS

Sputum cellularity data from two previous prospective studies involving children with asthma were re-evaluated and categorized into two inflammatory phenotypes: eosinophilic (>2.5% eosinophils) and noneosinophilic (≤2.5% eosinophils). Baseline values and follow-up sputum inflammatory phenotype classification were compared in children with asthma during stable and exacerbation phases.

RESULTS

Thirteen of 32 children (41%) with stable asthma demonstrated a change in sputum inflammatory phenotype 8 weeks later. In a different second cohort, both sputum eosinophils and neutrophils percentages increased and peaked on Day 1 of asthma exacerbation, but compared with baseline, 22% (2/9) and 13% (1/8) of these children had their sputum phenotype categorization changed on Day 1 and Day 3 of exacerbation, respectively.

CONCLUSION

In children with asthma, sputum inflammatory phenotypes are variable in both stable and exacerbation phases, in contrast to data in adults.

Upper Respiratory Tract Infection-Associated Acute Cough and the Urge to Cough: New Insights for Clinical Practice

Upper respiratory tract infection (URTI)-associated acute cough is the most common symptom both in children and adults worldwide and causes economic and social problems with significant implications for the patient, the patient's family, and the health care system. New pathogenic mechanisms in acute cough, including the urge to cough (UTC) mechanisms, have been recently identified. The brainstem neural network, pharyngeal sensory innervation, airway mechanical stimulation, inflammatory mediators, and postnasal drip actively participate in the onset and maintenance of acute cough and the urge to cough phenomenon. However, there is still no effective pharmacological treatment capable of interfering with the pathophysiologic mechanisms involved in URTI-associated acute cough. Moreover, severe adverse events frequently occur in administering such cough medications, mainly in children. New evidence has been provided concerning polysaccharides, resins, and honey as potential cough relievers with high antitussive efficiency, effect on the UTC, and minimal side effects.

Development of Machine Learning for Asthmatic and Healthy Voluntary Cough Sounds: A Proof of Concept Study

(1) Background: Cough is a major presentation in childhood asthma. Here, we aim to develop a machine-learning based cough sound classifier for asthmatic and healthy children. (2) Methods: Children less than 16 years old were randomly recruited in a Children’s Hospital, from February 2017 to April 2018, and were divided into 2 cohorts—healthy children and children with acute asthma presenting with cough. Children with other concurrent respiratory conditions were excluded in the asthmatic cohort. Demographic data, duration of cough, and history of respiratory status were obtained. Children were instructed to produce voluntary cough sounds. These clinically labeled cough sounds were randomly divided into training and testing sets. Audio features such as Mel-Frequency Cepstral Coefficients and Constant-Q Cepstral Coefficients were extracted. Using a training set, a classification model was developed with Gaussian Mixture Model–Universal Background Model (GMM-UBM). Its predictive performance was tested using the test set against the physicians’ labels. (3) Results: Asthmatic cough sounds from 89 children (totaling 1192 cough sounds) and healthy coughs from 89 children (totaling 1140 cough sounds) were analyzed. The sensitivity and specificity of the audio-based classification model was 82.81% and 84.76%, respectively, when differentiating coughs from asthmatic children versus coughs from ‘healthy’ children. (4) Conclusion: Audio-based classification using machine learning is a potentially useful technique in assisting the differentiation of asthmatic cough sounds from healthy voluntary cough sounds in children.

Diagnostic value of bronchoalveolar lavage in children with nonresponding community-acquired pneumonia

BACKGROUND

Community-acquired pneumonia (CAP) is a common cause of morbidity and mortality in hospitalized children. In CAP, causative agents are seldom identified using noninvasive diagnostic procedures. For those children not responding to empiric antibiotic therapy, it is vital to identify the causative pathogens for further management.

METHODS

We aimed to determine the usefulness of identifying the causative agents by bronchoalveolar lavage (BAL) in hospitalized children with nonresponding CAP. Ninety children hospitalized for CAP and treated with empiric antibiotics but having persistent fever ≥48 hours were enrolled, and their BAL data were retrospectively reviewed.

RESULTS

Aerobic bacteria were isolated from 38 (42%) of 90 cultures, and anaerobic bacteria were isolated from eight (24%) of 33 cultures. The bacteria isolated most frequently were Streptococcus viridians (26.3%), Pseudomonas aeruginosa (23.7%), and Staphylococcus aureus (15.8%). Streptococcus pneumoniae was isolated from the BALs of only two children, and Haemophilus influenzae from none. For positive aerobic culture results, BAL results guided modifications of antibiotic regimens in 21 episodes (21 of 38, 55.3%).

CONCLUSION

BAL results guided a change of antimicrobials in 55% of children with positive aerobic cultures (29% of all children in the study) and contributed to a high rate of successful therapy.

Feasibility of a Peer-Led Asthma and Smoking Prevention Project in Australian Schools with High Indigenous Youth

BACKGROUND

The high global burden of asthma and tobacco smoking among Indigenous people may potentially be reduced by appropriate interventions that target prevention of tobacco smoke uptake and improved asthma management. The latter includes targeted treatment based on airway inflammation. We undertook a feasibility study in two Darwin schools with a high proportion of Indigenous youth to determine the feasibility of an innovative, peer-led, school-based education program called the Asthma and Smoking Prevention Project (ASPP). A subset of children with reported persistent respiratory symptoms were also clinically evaluated to determine the lower airway inflammatory profile and optimize asthma management.

METHODS

The ASPP is founded on an evidence-based three-step program and targets improving asthma management and preventing the uptake of tobacco smoking. The program uses a student-centered approach in which senior students (peer leaders) deliver the ASPP to Grade 7 students using activities, videos, and games. Students completed questionnaires related to asthma and smoking at baseline and 3 months after program delivery. Students with respiratory symptoms at 3 months were invited for a comprehensive clinical evaluation and tests including sputum induction.

RESULTS

The ASPP was well received. Of the 203 students involved, 56 (28%) were Indigenous and 70% completed baseline and follow-up questionnaires. Self-reported asthma was high (19%), 10% of students reported smoking and 63% reported exposure to tobacco at home. Of the 22 students who were clinically evaluated, 41% were Indigenous. Clinically important airway inflammation was high; 23% had Fractional Exhaled Nitric Oxide Levels ≥35 ppb, 88% had airway neutrophilia (>15%), and 29% had airway eosinophilia (>2.5%). Optimization of medication and management was required in 59% of students.

CONCLUSION

Our study has demonstrated the implementation of the ASPP was well received by the schools as well as by the students. The high prevalence of clinically important airway inflammation and suboptimal asthma management highlights the need for a community-based study on persistent respiratory symptoms in adolescents to reduce the burden of chronic lung disease particularly for Indigenous Australians.

Types, frequency and impact of asthma triggers on patients' lives: a quantitative study in five European countries

OBJECTIVE

To identify the types, frequency and impact of asthma triggers and the relationship to asthma control among adults with asthma in Europe.

METHODS

Adults with self-reported physician-diagnosed asthma receiving maintenance asthma treatment and self-reported exposure to known asthma triggers completed an online questionnaire; a subset completed a diary over 3-4 weeks. Information on asthma control (Asthma Control Test™ [ACT]), asthma triggers, frequency of exposure and behaviours in response or to avoid asthma triggers and the perceived impact on daily life was captured. A post-hoc analysis evaluated the impact of high trigger burden on the frequency of severe asthma exacerbations, hospitalisations and days lost at work/study.

RESULTS

A total of 1202 adults participated and 177 completed the diary. Asthma was uncontrolled for the majority (76%) of participants and most (52%) reported exposure to 6-15 asthma triggers. As trigger burden increased, behavioural changes to manage trigger exposure had a significantly increased impact on daily life (p < 0.0001) and job choice (p = 0.002). Participants reporting a high trigger burden (>16) were more likely to report uncontrolled asthma than those with a low trigger burden (1-5). Participants with a high trigger burden had previously experienced on average two more severe asthma attacks during a lifetime (p < 0.001), two more hospitalisations (p < 0.001) and 3.5 more missed days at work or study in the last year due to their asthma (p < 0.001) than those with a low trigger burden.

CONCLUSIONS

Adults with asthma reporting a high trigger burden (>16 different triggers) experience more severe asthma attacks than those reporting lower trigger burdens.

An overview of the pediatric medications for the symptomatic treatment of allergic rhinitis, cough, and cold

Upper respiratory infections and allergic rhinitis are common diseases in children. In recent years, U.S. Food and Drug Administration has been promoting pediatric drug development with marketing exclusivity incentives and requirements. The assessment of clinical pharmacology, efficacy, and safety data has facilitated pediatric drug development and provided appropriate labeling for pediatric use. Regulatory decision making involves multiple evaluation processes, including drug exposure comparison between adult and pediatric population, formulation bridging, dose selection, and evaluation of efficacy and safety in pediatric patients. This article reviews the pediatric drugs indicated for cough, cold, and allergic rhinitis, focusing on the utility of clinical pharmacology, safety, and efficacy data in determining the pediatric dosing regimen and the approaches taken for regulatory decision making.

Bronchoscopy contributes to the clinical management of indigenous children newly diagnosed with bronchiectasis

BACKGROUND

Some pediatric centers perform flexible bronchoscopy (FB) routinely when bronchiectasis is suspected. However, there are no published data evaluating this practice.

OBJECTIVE

To evaluate the contribution of FB and bronchoalveolar lavage (BAL) to the initial management of children newly diagnosed with non-cystic fibrosis (CF) bronchiectasis.

METHOD

We examined FB and BAL data collected prospectively in 56 children aged 0.8-9.8 years during initial investigations for bronchiectasis. Investigations contributed to management if any of the following were identified: (1) airway obstruction requiring additional intervention, (2) lower airway eosinophilia (BAL eosinophils >2.5%), or (3) BAL fluid culture >10(4) colony-forming units/ml of a respiratory bacterial pathogen requiring change from usual empiric antibiotics.

RESULTS

Of the 56 children undergoing FB, there were 25 occasions in 23 children where these procedures altered empiric treatment. Lower airway eosinophilia was identified in 19 (34%) children, BAL microbiology results led to antibiotic changes in 5 (9%) and an unsuspected foreign body was found in another (2%). Strongyloides serology was performed in 38 children, including 12 of the 19 with airway eosinophilia, and was positive in 5 of these 12 children (42%).

CONCLUSION

Contrary to some expert recommendations that FB should only be performed when bronchiectasis is localized, our data suggest that FB with BAL should at least be included in the initial investigations of Indigenous children with non-CF bronchiectasis.

An observational study on cough in children: epidemiology, impact on quality of sleep and treatment outcome

Background

Cough is one of the most frequent symptoms in children and is the most common symptom for which children visit a health care provider.

Methods

This is an observational study on acute cough associated with upper respiratory tract infection (URTI) in children. The study evaluates the epidemiology and impact of cough on quality of sleep and children's activities, and the outcome of cough with antitussive treatments in pediatric routine clinical practice. Study assessments were performed through a pediatric cough questionnaire (PCQ), developed by the Italian Society of Cough Study. A total of 433 children visited by family care pediatricians for acute cough due to a URTI were enrolled in this study, with mean age of 6.1 years (SD 3.6). Cough type, duration, severity and frequency, cough impact on sleep disturbances of children and parents and on school and sport activities were assessed at baseline. In a subset of 241 children who were either treated with antitussive drugs (levodropropizine n = 101, central antitussives n = 60) or received no treatment (n = 80), the outcome of cough after 6 days was analyzed in terms of resolution, improvement, no change, or worsening. Descriptive analysis, χ² test, and multivariate analysis with stepwise logistic regression were performed.

Results

Cough disturbed sleep in 88% of children and 72% of parents. In children treated with cough suppressants, the duration, type, intensity, and frequency cough were similar at baseline in the two groups respectively treated with levodropropizine and central antitussives (cloperastine and codeine). Both levodropropizine and central drugs reduced cough intensity and frequency. However, percentage of cough resolution was higher with levodropropizine than with central antitussives (47% vs. 28% respectively, p = 0.0012).

Conclusions

Acute cough disturbs sleep in most children and their parents. Both levodropropizine and central antitussives reduced cough intensity, with levodropropizine producing a higher cough resolution rate.

Do sex and atopy influence cough outcome measurements in children?

BACKGROUND

Despite the commonality of cough and its burden, there are no published data on the relationship between atopy or sex on objectively measured cough frequency or subjective cough scores in children. In 202 children with and without cough, we determined the effect of sex and atopy on validated cough outcome measurements (cough receptor sensitivity [CRS], objective cough counts, and cough scores). We hypothesized that in contrast to adult data, sex does not influence cough outcome measures, and atopy is not a determinant of these cough measurements.

METHODS

We combined data from four previous studies. Atopy (skin prick test), the concentration of capsaicin causing two and five or more coughs (C2 and C5, respectively), objectively measured cough frequency, and cough scores were determined and their relationship explored. The children's (93 girls, 109 boys) mean age was 10.6 years (SD 2.9), and 56% had atopy.

RESULTS

In multivariate analysis, CRS was influenced by age (C2 coefficient, 5.9; P = .034; C5 coefficient, 29.1; P = .0001). Atopy and sex did not significantly influence any of the cough outcomes (cough counts, C2, C5, cough score) in control subjects and children with cough.

CONCLUSIONS

Atopy does not influence important cough outcome measures in children with and without chronic cough. However, age, but not sex, influences CRS in children. Unlike adult data, sex does not affect objective counts or cough score in children with and without chronic cough. Studies on cough in children should be age matched, but matching for atopic status and sex is less important.

Asthma and protracted bronchitis: who fares better during an acute respiratory infection?

AIM

Acute respiratory infections (ARI) are common in children, and symptoms range from days to weeks. The aim of this study was to determine if children with asthma have more severe ARI episodes compared with children with protracted bronchitis and controls.

METHODS

Parents prospectively scored their child's next ARI using the Canadian acute respiratory illness and flu scale (CARIFS) and a validated cough diary (on days 1-7, 10 and 14 of illness). Children were age- and season-matched.

RESULTS

On days 10 and 14 of illness, children with protracted bronchitis had significantly higher median CARIFS when compared with children with asthma and healthy controls. On day 14, the median CARIFS were: asthma = 4.1 (interquartile range (IQR) 4.0), protracted bronchitis = 19.6 (IQR 25.8) and controls = 4.1 (IQR 5.25). The median cough score was significantly different between groups on days 1, 7, 10 and 14 (P < 0.001). A significantly higher proportion of children with protracted bronchitis (63%) were still coughing at day 14 in comparison with children with asthma (24%) and healthy controls (26%).

CONCLUSION

Children with protracted bronchitis had the most severe ARI symptoms and higher percentage of respiratory morbidity at day 14 in comparison with children with asthma and healthy controls.

A 5- versus 3-day course of oral corticosteroids for children with asthma exacerbations who are not hospitalised: a randomised controlled trial

OBJECTIVE

To determine whether a 5-day course of oral prednisolone is superior to a 3-day course in reducing the 2-week morbidity of children with asthma exacerbations who are not hospitalised.

DESIGN, SETTING AND PARTICIPANTS

Double-blind randomised controlled trial of asthma outcomes following a 5-day course of oral prednisolone (1 mg/kg) compared with a 3-day course of prednisolone plus placebo for 2 days. Participants were children aged 2-15 years who presented to the emergency departments of three Queensland hospitals between March 2004 and February 2007 with an acute exacerbation of asthma, but were not hospitalised. Sample size was defined a priori for a study power of 90%.

MAIN OUTCOME MEASURES

Difference in proportion of children who were symptom-free at Day 7, as measured by intention-to-treat (ITT) and per-protocol analysis; quality of life (QOL) on Days 7 and 14.

RESULTS

201 children were enrolled, and there was an 82% completion rate. There was no difference between groups in the proportion of children who were symptom-free (observed difference, 0.04 [95% CI, - 0.09 to 0.18] by ITT analysis; 0.04 [95% CI, - 0.17 to 0.09] by per-protocol analysis). There was also no difference between groups in QOL (P = 0.42). The difference between groups for the primary outcome was within the equivalence range calculated post priori.

CONCLUSION

A 5-day course of oral prednisolone confers no advantage over a 3-day course for children with asthma exacerbations who are not hospitalised.

TRIAL REGISTRATION

Australian Clinical Trials Registry ACTRN012605000305628.

Eosinophilic airway inflammation and the prognosis of childhood asthma

BACKGROUND

Eosinophilic airway inflammation is a key pathophysiological feature of asthma that can predict treatment response. However, the prognostic value of sputum eosinophilia is not established.

OBJECTIVE

The aim of this study was to determine the influence of induced sputum eosinophilia on the prognosis of childhood asthma.

METHODS

A cohort of children with asthma was evaluated by induced sputum analysis at inception and classified as having either eosinophilic asthma (EA) (sputum eosinophils >2.5%) or non-eosinophilic asthma (NEA). After a mean follow-up period of 5 years, eligible subjects (n=83) were contacted and 69 subjects (33 EA, 36 NEA) evaluated. The children had a mean age of 15.9 years, and 61% were male.

RESULTS

Children with EA reported more wheeze during the follow-up period (27% vs. 6% wheezed most years; P<0.0001), increased night waking during the past 12 months (28% vs. 3% reported weekly waking; P=0.01), and greater impairment of quality of life due to asthma (P=0.04). Subsequent beta2-agonist use was increased in children with EA (P=0.02), although there was no difference in corticosteroid use. In EA, subsequent forced expiratory volume in 1 s/forced vital capacity was lower (79% vs. 86%; P=0.01) and grass pollen allergy was more prevalent (77% vs. 27%; P=0.006).

CONCLUSION

In children, eosinophilic airway inflammation is associated with deteriorating asthma over time. This is consistent with the hypothesis that airway inflammation has an adverse impact on the prognosis of childhood asthma, and suggests a role for monitoring inflammation in asthma management.

Antibiotic treatment of wheezing in children with asthma: what is the practice?

OBJECTIVE

Antibiotics are not recommended for the treatment of wheezing in children with asthma, but little is known about their use. This study was undertaken to evaluate trends and determinants of antibiotic use in children with wheezing during the fiscal years 1995 through 2001.

METHODS

Using the population-based health care and prescription databases in Manitoba, Canada, this descriptive study examined time trends in antibiotic prescription use for wheezing episodes in a population of children with asthma. The likelihood of receiving an antibiotic prescription according to child and physician characteristics also was determined. Annual population-based rates of antibiotic prescriptions for wheezing episodes were modeled by age and antibiotic class, using general estimating equations. The odds ratio for receiving an antibiotic prescription according to child demographics and physician factors was determined from hierarchical linear modeling.

RESULTS

The antibiotic prescription rate for wheezing decreased by 28% from 708 prescriptions per 1000 children with asthma in 1995 to 511 prescriptions in 2001. Fifteen-fold increases in use were observed for broader spectrum macrolides in preschool children. Twenty-three percent of physician visits for wheezing resulted in an immediate antibiotic prescription, but this percentage increased to 64% for antibiotics that were received within 7 days of the episode. General practitioners prescribed antibiotics more often than did pediatricians. Physicians who were not trained in Canada or the United States were 40% more likely to prescribe antibiotics than their counterparts.

CONCLUSIONS

Antibiotic use for wheezing in children declined in the 1990s, but the increased use of broader spectrum macrolides has implications for antibiotic resistance. A link between antibiotic prescribing and physician specialty and location of training identifies opportunities for intervention.

Cough frequency in children with mild asthma correlates with sputum neutrophil count

BACKGROUND

A study was undertaken to measure cough frequency in children with stable asthma using a validated monitoring device, and to assess the correlation between cough frequency and the degree and type of airway inflammation.

METHODS

Thirty six children of median age 11.5 years (interquartile range (IQR) 9-14) with stable asthma were recruited. They underwent spirometric testing, exhaled nitric oxide (eNO) measurement, sputum induction for differential cell count, and ambulatory cough monitoring for 24 hours. Coughing episodes were counted both as individual spikes and as clusters.

RESULTS

All children had mild intermittent asthma and their median forced expiratory volume in 1 second and eNO were 83.3% (IQR 81.1-97.6) and 56.1 ppb (IQR 37.4-105), respectively. The median number of cough episodes per day was 25.5 (IQR 16-42.8). Sputum induction was successful in 69% of the subjects and cough frequency was found to have a significant positive correlation with sputum neutrophil count (r = 0.833, p = 0.0001).

CONCLUSIONS

Children with stable mild asthma have increased cough frequency that might be driven by a neutrophilic inflammatory pathway.

Cough and asthma

The relationship between cough and asthma is complex. Epidemiological studies now suggest that most children with recurrent cough who do not wheeze do not have asthma. These children are commonly described as having non-specific cough that appears to be due to increased cough receptor sensitivity during the coughing episode. Children with asthma who cough have also been shown to have increased cough receptor sensitivity during an acute exacerbation. Cough severity does not generally correlate with asthma severity. Apart from wheeze and dyspnoea, there are no clear distinguishing features to separate asthma from non-specific cough. To date, no specific treatment has clearly been shown to benefit children with non-specific cough. Although a trial of asthma treatment may be justified in these children, it is preferable to cease rather than escalate treatment if there is no response. In children with asthma who cough, cough should not be used as the predominant symptom to direct asthma therapy.

Guidelines for evaluating chronic cough in pediatrics: ACCP evidence-based clinical practice guidelines

OBJECTIVES

To review relevant literature and present evidence-based guidelines to assist general and specialist medical practitioners in the evaluation and management of children who present with chronic cough.

METHODOLOGY

The Cochrane, MEDLINE, and EMBASE databases, review articles, and reference lists of relevant articles were searched and reviewed by a single author. The date of the last comprehensive search was December 5, 2003, and that of the Cochrane database was November 7, 2004. The authors' own databases and expertise identified additional articles.

RESULTS/CONCLUSIONS

Pediatric chronic cough (ie, cough in children aged <15 years) is defined as a daily cough lasting for >4 weeks. This time frame was chosen based on the natural history of URTIs in children and differs from the definition of chronic cough in adults. In this guideline, only chronic cough will be discussed. Chronic cough is subdivided into specific cough (ie, cough associated with other symptoms and signs suggestive of an associated or underlying problem) and nonspecific cough (ie, dry cough in the absence of an identifiable respiratory disease of known etiology). The majority of this section focuses on nonspecific cough, as specific cough encompasses the entire spectrum of pediatric pulmonology. A review of the literature revealed few randomized controlled trials for treatment of nonspecific cough. Management guidelines are summarized in two pathways. Recommendations are derived from a systematic review of the literature and were integrated with expert opinion. They are a general guideline only, do not substitute for sound clinical judgment, and are not intended to be used as a protocol for the management of all children with a coughing illness. Children (aged <15 years) with cough should be managed according to child-specific guidelines, which differ from those for adults as the etiologic factors and treatments for children are sometimes different from those for adults. Cough in children should be treated based on etiology, and there is no evidence for using medications for the symptomatic relief of cough. If medications are used, it is imperative that the children are followed up and therapy with the medications stopped if there is no effect on the cough within an expected time frame. An evaluation of the time to response is important. Irrespective of diagnosis, environmental influences and parental expectations should be discussed and managed accordingly. Cough often impacts the quality of life of both children and parents, and the exploration of parental expectations and fears is often valuable in the management of cough in children.

Control of mild to moderate asthma over 1-year with the combination of salmeterol and fluticasone propionate

OBJECTIVE

The aim of this study was to assess asthma control using salmeterol plus fluticasone propionate (FP) in combination (SFC) versus salmeterol or FP as monotherapy in patients with mild to moderate asthma.

METHODS

In this randomised, double-blind, parallel-group study, 322 symptomatic patients were recruited, of which 282 were randomised to receive either salmeterol (50 microg), FP (250 microg), or SFC (50 microg/250 microg), via a single Diskus inhaler twice daily for 12 months. Outcome variables included the number of patients requiring an increase in study medication and the number experiencing 2 exacerbations during the 12-month treatment period. Airway hyper-responsiveness (AHR) and lung function tests were performed at clinic visits. Peak expiratory flow, rescue medication use, symptom scores and adverse events were recorded in diary cards.

RESULTS

Fewer patients required an increase in study medication with SFC (10.5%) than with either FP (34.8%) or salmeterol (61.1%) (P<0.001). Significantly fewer patients experienced 2 exacerbations with SFC (4.2%), compared with FP (17.4%; P<0.01) or salmeterol (40%; P<0.001). SFC improved AHR to a significantly greater extent than FP (methacholine PC20=1.8 mg/ml vs. 1.1 mg/ml; P<0.05) or salmeterol (methacholine PC20=1.8 mg/ml vs. 0.7 mg/ml; P<0.001).

CONCLUSIONS

The protection against exacerbations may be attributed to better control of inflammation, AHR and lung function parameters achieved with salmeterol and FP in combination, compared with either treatment alone.

Cough: are children really different to adults?

Worldwide paediatricians advocate that children should be managed differently from adults. In this article, similarities and differences between children and adults related to cough are presented. Physiologically, the cough pathway is closely linked to the control of breathing (the central respiratory pattern generator). As respiratory control and associated reflexes undergo a maturation process, it is expected that the cough would likewise undergo developmental stages as well. Clinically, the 'big three' causes of chronic cough in adults (asthma, post-nasal drip and gastroesophageal reflux) are far less common causes of chronic cough in children. This has been repeatedly shown by different groups in both clinical and epidemiological studies. Therapeutically, some medications used empirically for cough in adults have little role in paediatrics. For example, anti-histamines (in particular H1 antagonists) recommended as a front-line empirical treatment of chronic cough in adults have no effect in paediatric cough. Instead it is associated with adverse reactions and toxicity. Similarly, codeine and its derivatives used widely for cough in adults are not efficacious in children and are contraindicated in young children. Corticosteroids, the other front-line empirical therapy recommended for adults, are also minimally (if at all) efficacious for treating non-specific cough in children. In summary, current data support that management guidelines for paediatric cough should be different to those in adults as the aetiological factors and treatment in children significantly differ to those in adults.

Modelling of peak-flow wall shear stress in major airways of the lung

Some respiratory diseases result in the inflammation of the lung airway epithelium. An associated chronic cough, as found in many cases of asthma and in long-term smokers, can exacerbate damage to the epithelial layer. It has been proposed that wall shear stresses, created by peak expiratory flow-rates during a coughing episode, are responsible. The work here uses a computational fluid dynamics technique to model peak expiratory flow in the trachea and major lung bronchi. Calculated wall shear stress values are compared to a limited set of published measurements taken from a physical model. The measurements are discussed in the context of a flow study of a complex bronchial network. A more complete picture is achieved by the calculation method, indicating, in some cases, higher maximum wall shear stresses than measured, confirming the original findings of the experimental work. Recommendations are made as to where further work would be beneficial to medical applications.

Cough, wheezing and asthma in children: lesson from the past

Recurrent cough is an important medical and sometimes frustrating problem encountered by pediatricians, especially if it is not associated with wheeze or other evidence of systemic disease. In the past, many children with chronic cough have been diagnosed as asthmatic. However, epidemiological, clinical and laboratory studies conducted over the last ten years elucidated many aspects of the relationship between cough and bronchoconstriction. It is difficult to make a diagnosis of asthma on cough alone, but the setting in which the patient is seen (i.e., in a primary care setting or ain a specialistic clinic) may address doctors to the right diagnosis. A prudent ''wait and see'' approach may be useful in many occasions.

Cough frequency in children with stable asthma: correlation with lung function, exhaled nitric oxide, and sputum eosinophil count

BACKGROUND

A study was undertaken to assess the correlation between cough frequency in asthmatic children with lung function and two non-invasive markers of airway inflammation.

METHODS

Thirty two children of median age 12.0 years (interquartile range (IQR) 9.5-13.4) with stable asthma were recruited. They underwent spirometric testing, exhaled nitric oxide (eNO) measurement, sputum induction for differential cell count, and ambulatory cough monitoring over 17 hours and 40 minutes. Coughing episodes were counted both as individual spikes and as clusters.

RESULTS

Complete cough frequency data were available in 29 children (90%) and their median forced expiratory volume in 1 second (FEV1) and eNO were 88.5% (IQR 79.5-98) and 23.9 ppb (IQR 11.4-41.5), respectively. The median number of cough episodes was 14 (IQR 7.0-24.0) which was significantly higher than that of normal children (6.7 (IQR 4.1-10.5), p<0.001). Sputum induction was successful in 61% of the subjects; the median induced sputum eosinophil count was 0.05% (IQR 0-9.0). Cough frequency was found to have a significant positive correlation with eNO (Spearman's r =0.781, p<0.001) but not with FEV1 or sputum eosinophil count (r =-0.270, p=0.157; r =0.173, p=0.508, respectively).

CONCLUSIONS

Children with stable asthma have increased cough frequency compared with normal controls and cough frequency was greater during the day than at night. Cough may be a more sensitive marker of airway inflammation than simple spirometry.

Relation between measurements of cough severity

BACKGROUND

In asthma, measurements of airway inflammation correlate poorly with clinical markers and airway hyperresponsiveness. While the relation between determinants of asthma severity is known, that for cough is unknown. We hypothesised that cough sensitivity changes relate to changes in cough scores and objectively measured cough frequency.

AIMS

To examine the relation between commonly used outcome measurements of cough severity in children.

METHODS

The concentration of capsaicin causing two and five or more coughs (C2 and C5 respectively), cough frequency objectively measured using an ambulatory cough meter, and parent and child recorded subjective cough scores were determined in 40 children with recurrent cough on two occasions.

RESULTS

On occasion one, log cough frequency significantly correlated with parent and child recorded log cough score (r(s) = 0.32, p = 0.05; and r(s) = 0.32, p = 0.046 respectively) and significantly negatively correlated with log C2 (r(s)= -0.5, p = 0.005). Subjective cough scores did not relate to either C2 or C5. On occasion two, the relation between cough frequency and C2 and C5 measures was lost, but C2 had a weak but significant relation to parent recorded cough score (r(s) = -0.38, p = 0.047). When the changes in the log values were determined, C5 but not C2 significantly related to cough frequency.

CONCLUSION

In children, measures of cough sensitivity have a weak relation with cough frequency. Subjective cough scores have a stronger and consistent relation with cough frequency. These cough severity indices measure different aspects of cough. The choice of indices depends on the reason for performing the measurement.

Relationship between cough, cough receptor sensitivity and asthma in children

In childhood asthma, cough is a major symptom in some but not in others. There is only limited data on the frequency, severity and prevalence of cough in children with classical asthma. Studies have largely shown no relationship between cough frequency and cough receptor sensitivity with various asthma severity indices. However relating cough severity with asthma severity is limited by various methodological and sensitivity issues, and these are presented in this paper. Mild asthma exacerbations in a group of children with cough as a dominant symptom were characterised by an increase in cough severity (daytime cough scores) and eosinophilic inflammation but not neutrophilic inflammation. However neither cough receptor sensitivity or cough scores related to airway IL-8, eosinophil cationic protein, myeloperoxidase or serum eosinophil cationic protein, and, asthma scores consistently related to cough score only early in the asthma exacerbation phase.