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Biomedical subjects

P G Gibson

Publications and source records attributed to P G Gibson.

At least 19 recordsLinked to original sources
PubMed2002

Macrolides for chronic asthma.

BACKGROUND: Asthma is a chronic disease of the airways in which inflammation of the respiratory mucosa plays a crucial role. The mechanisms responsible for the maintaining of this inflammatory response are only partially known and there is evidence that a role could be paid by chronic infection by intracellular pathogens (such as Chlamydia pneumoniae). Macrolides are antibiotics with both antimicrobial and anti-inflammatory activities and thus their use in asthmatic patients could lead to reduction of the airways inflammation and therefore improvement of symptoms and pulmonary function. OBJECTIVES: To determine whether macrolides are effective in the management of patients with chronic asthma. SEARCH STRATEGY: We searched MEDLINE, EMBASE and CINAHL up to May 2001. This was also supplemented by manually searching bibliographies of previously published reviews, conference proceedings, and contacting study authors. All languages were included in the initial search. SELECTION CRITERIA: Randomised, controlled clinical trials involving both children and adult patients with chronic asthma treated with macrolides for more than 4 weeks, versus placebo. DATA COLLECTION AND ANALYSIS: Two reviewers independently examined all identified articles. Two reviewers reviewed the full text of any potentially relevant article independently. MAIN RESULTS: The initial search retrieved 95 studies. Preliminary evaluation identified 20 studies that were potentially eligible. Five (357 patients) met the entry criteria. The entry criteria for the primary trials differed, but all recruited a specific subgroup of patients (eg severe oral steroid dependent, aspirin intolerant or evidence of Chlamydia pnuemoniae infection). There was a positive effect on symptoms (Standardised Mean Difference -1.25, 95% Confidence Intervals (CI) -1.80, -0.70) and markers of eosinophilic inflammation; eg sputum eosinophils Weighted Mean difference -78.5, 95%CI -90.8, -66.1). Tests of oral corticosteroid-sparing effects have not yet been performed on the newer agents such as roxithromycin and clarithromycin. REVIEWER'S CONCLUSIONS: Considering the small number of patients studied, there is insufficient evidence to support or to refute the use of macrolides in patients with chronic asthma. Further studies are needed in particular to clarify the potential role of macrolides in some subgroups of asthmatics such as those with evidence of chronic bacterial infection.

Anti-Bacterial Agents↗
PubMed2002

Cough, airway inflammation, and mild asthma exacerbation.

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 (FEV(1), FEV(1) 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.

Acute Disease↗
PubMed2002

Eosinophilic bronchitis: clinical manifestations and implications for treatment.

Airway inflammation with eosinophils is now reported to occur not only in asthma but in other airway diseases such as cough variant asthma, chronic cough, atopic cough, episodic symptoms without asthma, allergic rhinitis, and COPD. Although the prevalence of eosinophilic bronchitis (EB) is less than in asthma, the causes, mechanisms and treatment of EB in these conditions appears to be similar to asthma where allergen induced IL-5 secretion and symptoms are readily responsive to inhaled corticosteroids. The prognosis of EB without asthma is not known but it may be a precursor for asthma and, if so, recognition of this syndrome may permit effective treatment and reduction in the rising prevalence of asthma. Induced sputum analysis allows recognition of EB in clinical practice. The place of the asthma treatment paradigm with early and sustained corticosteroid treatment needs to be defined in EB without asthma. Airway wall remodelling can occur in rhinitis, COPD, and cough variant asthma with EB. The mechanisms and long term implications of this complication in EB without asthma need to be clarified.

Asthma↗
PubMed2002

Neutrophil degranulation and cell lysis is associated with clinical severity in virus-induced asthma.

Acute exacerbations of asthma are frequently caused by viral infections, but the inflammatory mechanisms in virus-induced asthma are poorly understood. The aim of the present study was to determine whether viral infection in acute asthma was associated with increased sputum neutrophil degranulation and increased cellular lysis and whether these changes are related to clinical severity. Adults (n=49) presenting to the emergency department with acute asthma were examined for infection by means of sputum direct-fluorescence antigen detection, sputum culture, and sputum polymerase chain reaction for Mycoplasma, Chlamydia and Legionella pneumophila, and all common respiratory viruses. Subjects infected with one of these agents were classed as having an infective exacerbation. Spirometry and sputum induction were performed on presentation and 4-5 weeks later. Thirty-seven subjects (76%) had virus infection and acute asthma. Those with virus infection had increased sputum neutrophils (p<0.05) and increased neutrophil elastase (p<0.05), this was related to increased elevated sputum lactate dehydrogenase (LDH). Subjects with noninfective asthma had an increase in the proportion of sputum eosinophils. Both groups had elevated sputum eosinophil cationic protein (ECP) concentrations. Higher levels of sputum LDH and ECP were associated with a longer hospital stay. Virus infection and acute asthma is associated with neutrophilic inflammation, cell lysis and more severe clinical disease.

Adolescent↗
PubMed2001

The tolerability, safety, and success of sputum induction and combined hypertonic saline challenge in children.

Induced sputum using hypertonic saline (HS) is a useful research tool to study airway inflammation (AI). HS provocation testing can also be used to measure airway hyperresponsiveness (AHR). A combined HS challenge and sputum induction procedure has been developed to permit assessment of AI and AHR in a single test. The aim of this study is to report the success and tolerability of sputum induction alone, and in combination with a HS bronchial provocation challenge. Sputum induction alone was performed with beta2-agonist pretreatment. In the combined challenge, no beta2-agonist pretreatment was used. A high-output ultrasonic nebulizer with valve box and tubing were used to deliver 4.5% saline in doubling time periods from 0.5 s to 4 min. Outcomes assessed were completion of the test protocol, adequacy of sputum samples, decrease in FEV1, and adverse effects during the procedure. Fifty-three children who underwent a sputum induction alone, and 182 children who underwent a combined sputum induction and bronchial provocation using HS. Sputum induction alone was well tolerated, with 98% of children completing the procedure and only 4% experiencing a significant (> 15%) fall in FEV1. An adequate sample of sputum was obtained in 92% of children. The combined challenge was completed by 90% of children. A distressing cough occurred in 13% of children and irritation of the mucosa in 1% of children. In the combined challenge an adequate sample of sputum was obtained in significantly fewer children than with sputum induction alone (70% versus 92%, p < 0.05). Sputum cellular changes reflected the shorter nebulization time with sputum induction alone. We conclude that induction of sputum using HS after pretreatment with bronchodilator is well tolerated with a high success rate in children. Combining the HS challenge with sputum induction provides additional information and is a useful means of comparing AHR and AI simultaneously, but at the expense of having a reduced success rate in obtaining an adequate sample of sputum, as well as increased side effects.

Adolescent↗
PubMed2001

Airway eosinophilia is associated with wheeze but is uncommon in children with persistent cough and frequent chest colds.

The role of eosinophilic airway inflammation in the variant asthma syndromes of cough and chest colds is not well defined. We tested the hypothesis that children with persistent cough and chest colds have increased sputum eosinophils, similar to those with wheeze. The parents of 390 primary school children completed a symptoms questionnaire. Children with wheeze (n = 28), cough (n = 12), recurrent chest colds (n = 17), and no symptoms (control subjects, n = 26), underwent allergy skin prick tests, spirometry, hypertonic saline inhalation challenge, and sputum induction, and then completed a peak expiratory flow (PEF) and symptoms diary over a 2-mo period. Children with wheeze had significantly reduced PEF (p = 0.001) and higher sputum eosinophils when compared with the cough, chest cold, and control groups (3.1% versus 0.5%, 0%, 0%; p = 0.03). The prevalence of eosinophilic bronchitis (sputum eosinophils > 2.5%) was 45% in the wheeze group, which was significantly higher than the control group (9.35%, p = 0.04). Eosinophilic bronchitis was present in two children with cough (20%) and two with chest colds (15%, p > 0.05 versus control). In these groups, eosinophilic bronchitis was not associated with airway hyperresponsiveness (AHR) to hypertonic saline (p > 0.05). Children with cough and chest colds reported greater exposure to environmental tobacco smoke. In conclusion, this community-based survey of children with chronic respiratory symptoms has shown that wheeze is a good discriminator for the presence of eosinophilic bronchitis, and that persistent cough and recurrent chest colds without wheeze should not be considered a variant of asthma. Eosinophilic bronchitis did occur in a significant minority of these "variant asthma" syndromes.

Age Factors↗
PubMed2001

Alterations of placental vascular function in asthmatic pregnancies.

Asthma during pregnancy is associated with low-birthweight neonates at term but the mechanisms that cause this outcome are presently unknown. Changes in placental vascular function resulting from asthma or its treatment could contribute to altered fetal growth. We have prospectively followed women with asthma and a control group of women without asthma during their pregnancies, classified them based on asthma severity and glucocorticoid intake, and monitored fetal development and placental blood flow using Doppler ultrasound at 18 and 30 wk gestation. The placentae from these women were collected after delivery and vascular responses to dilator and constrictor agonists assessed using an in vitro placental perfusion method. At 18 wk gestation, umbilical artery flow velocity waveforms were significantly reduced in the moderate and severe asthmatic groups and in those women using high-dose inhaled glucocorticoid for the treatment of their asthma (ANOVA, p < 0.05). However, at 30 wk gestation there were no significant differences in umbilical artery flow velocity between control and asthmatic women (ANOVA, p > 0.05). Corticotropin-releasing hormone (CRH), a potent vasodilator that acts via the nitric oxide pathway, caused a dose-dependent vasodilatory response in all placentae in vitro. However, CRH-induced dilation was significantly reduced in moderate and severe asthmatics (ANOVA, p < 0.05). Vasoconstrictor responses to potassium chloride and prostaglandin F(2alpha) were reduced in placentae from moderate and severe asthmatic women (ANOVA, p < 0.05). These studies demonstrate significant differences in placental vascular function in pregnancies complicated by asthma, which may relate directly to the asthma or be a consequence of the associated glucocorticoid treatment. These changes in vascular function in asthmatic pregnancies may contribute to the low-birthweight outcome observed in this condition.

Adult↗
PubMed2001

Effect of peer led programme for asthma education in adolescents: cluster randomised controlled trial.

OBJECTIVE: To determine the effect of a peer led programme for asthma education on quality of life and related morbidity in adolescents with asthma. DESIGN: Cluster randomised controlled trial. SETTING: Six high schools in rural Australia. PARTICIPANTS: 272 students with recent wheeze, recruited from a cohort of 1515 students from two school years (mean age 12.5 and 15.5 years); 251 (92.3%) completed the study. INTERVENTION: A structured education programme for peers comprising three steps (the "Triple A Program"). MAIN OUTCOME MEASURES: Quality of life, school absenteeism, asthma attacks, and lung function. RESULTS: When adjusted for year and sex, mean total quality of life scores showed significant improvement in the intervention than control group. Clinically important improvement in quality of life (>0.5 units) occurred in 25% of students with asthma in the intervention group compared with 12% in the control group (P=0.01). The number needed to treat was 8 (95% confidence interval 4.5 to 35.7). The effect of the intervention was greatest in students in year 10 and in females. Significant improvements occurred in the activities domain (41% v 28%) and in the emotions domain (39% v 19%) in males in the intervention group. School absenteeism significantly decreased in the intervention group only. Asthma attacks at school increased in the control group only. CONCLUSION: The triple A programme leads to a clinically relevant improvement in quality of life and related morbidity in students with asthma. Wider dissemination of this programme in schools could play an important part in reducing the burden of asthma in adolescents.

Absenteeism↗
PubMed2001

Interventions for educating children who have attended the emergency room for asthma.

BACKGROUND: Asthma is one of the most common reasons for paediatric admissions to hospital, with substantial cost to the community. There is some evidence to suggest that many hospital admissions could be prevented with effective education about asthma and its management. OBJECTIVES: To conduct a systematic review of the literature in order to identify whether asthma education leads to improved health outcomes in children who have attended the emergency department for asthma. SEARCH STRATEGY: We searched the Cochrane Airways Group trials register, including Medline, Embase, and Cinahl databases, and reference lists of trials and review articles. SELECTION CRITERIA: Randomised controlled trials or controlled clinical trials of asthma education for children who had attended the emergency department for asthma, with or without hospitalisation, within the previous 12 months. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed trial quality and extracted data. Study authors were contacted for additional information. MAIN RESULTS: Eight trials involving 1407 patients were included, in all the education was provided by nurses or researchers. Compared to control (usual care or lower intensity education) education did not reduce subsequent emergency department (ED) visits [4 trials; relative risk (RR)= 0.87, 95% confidence interval (CI) 0.37 to 2.08], hospital admissions [5 trials; RR=0.74, 95% CI 0.38 to 1.46] and unscheduled doctor visits [5 trials; RR= 0.74, 95% CI 0.49 to 1.12). Each analysis showed evidence of heterogeneity among the studies (P<0.01). Subgroup analyses by the overall difference in scale of intervention between treatment and control groups (comprehensive programme versus information only) or the timing of the intervention/recruitment (early versus delayed) gave similar results to the main analysis and still revealed significant heterogeneity between trials. REVIEWER'S CONCLUSIONS: On the basis of the published trials, there is no firm evidence to support the use of asthma education for children who have attended the emergency department for asthma as a means of reducing subsequent ED visits, hospital admissions or unscheduled doctor visits. Some trials appeared to show clear evidence of benefit, but reasons for differences between these and the negative studies is not clear. More research is required

Asthma↗
PubMed2001

Safety of sputum induction with isotonic saline in adults with acute severe asthma.

BACKGROUND: Sputum induction is a safe and effective technique to study airway inflammation in stable asthma. However, it has the potential to induce bronchospasm and the safety and efficacy of the technique in acute asthma has not been determined. OBJECTIVE: The objective of this study was to evaluate the safety and efficacy of a protocol to induce sputum using isotonic saline in adults with acute exacerbations of asthma. METHODS: Adults (n = 47) presenting to the emergency room with acute asthma and an FEV1 > 1.0 L underwent supervised sputum induction with 0.9% saline delivered by an ultrasonic nebuliser. Induction was ceased if there was a fall of 20% or greater from baseline FEV1. RESULTS: Subjects had moderate to severe exacerbations of acute asthma. An adequate sputum sample was obtained in 87% of subjects. Four subjects ceased induction because of symptom distress. There was a fall > or = 20% in 28% of subjects. Bronchoconstriction was successfully reversed by salbutamol in all subjects. Predictors of significant bronchoconstriction were older age, use of ingested corticosteroids, and a requirement for high-dose nebulized salbutamol for the exacerbation. Maintenance long-acting beta2-agonist therapy protected against bronchoconstriction during sputum induction. CONCLUSIONS: Sputum induction in acute asthma using isotonic saline is highly efficacious in obtaining an adequate sputum sample. There is the potential for significant bronchoconstriction to occur but this can be managed safely with minimal discomfort to subjects.

Acute Disease↗
PubMed2001

Allergic bronchopulmonary aspergillosis: new concepts of pathogenesis and treatment.

Allergic bronchopulmonary aspergillosis (ABPA) is a condition that results from a hypersensitivity reaction to the fungus Aspergillus fumigatus. The purpose of the present review is to examine the pathogenesis of this condition and the evidence for treatments available. Allergic bronchopulmonary aspergillosis is characterized by an intense airway inflammation with eosinophils and the formation of mucus plugs. Clinically, there are periods of exacerbation and remission that may lead to proximal bronchiectasis and fibrotic lung disease. New evidence confirms the role of intense airway inflammation with eosinophils, but also suggests a role for interleukin (IL)-8/neutrophil-mediated inflammation in this process, and the potential deficiency of anti-inflammatory cytokines such as reduced IL-10. Treatment for ABPA has so far focused on corticosteroids to suppress eosinophilic airway inflammation. An expanding knowledge of the pathology of ABPA also suggests other therapies may be of potential benefit, particularly the use of azole antifungal agents. Allergic bronchopulmonary aspergillosis is itself an important complication of asthma and cystic fibrosis. A greater understanding of the condition is required to improve management and well-designed clinical trials need to be carried out to critically assess new and current treatments. In addition, the information gained from the studies of its pathogenesis has the potential to benefit our understanding of the disease processes in asthma and bronchiectasis.

Adrenal Cortex Hormones↗
PubMed2001

Oxidative stress in cystic fibrosis: dietary and metabolic factors.

OBJECTIVE: To examine oxidative stress in CF by measuring 8-iso-PGF2alpha and antioxidant defenses, in relation to dietary intake, immune function and clinical status. METHODS: We measured total plasma concentrations of 8-iso-PGF2alpha and dietary antioxidants (vitamin E, vitamin C, beta-carotene), erythrocyte antioxidant enzyme activities (glutathione peroxidase and superoxide dismutase), lung function and dietary intake in 21 CF subjects and 21 healthy age- and gender-matched controls. RESULTS: Total plasma 8-iso-PGF2alpha concentration (median [quartile 1-quartile 3]) was significantly higher in CF subjects compared to controls (214 pg/mL (155-331) vs. 135 pg/mL (101-168), p = 0.001). Neutrophil, monocyte and total white cell counts were elevated in the CF group and these correlated with 8-iso-PGF2alpha concentration. Despite similar dietary intake, lower plasma antioxidant concentrations were observed in the CF group (vitamin E, p < 0.001, vitamin C, p = 0.004, beta-carotene, p = 0.001). 8-iso-PGF2alpha correlated negatively with plasma vitamin E, C and beta-carotene concentrations. CONCLUSION: Oxidative stress is increased in CF patients, despite normal dietary antioxidant intake. The immune response appears to be a key factor causing oxidative stress. Antioxidant intervention aimed at reducing oxidative stress in CF needs to be assessed.

Adolescent↗
PubMed2001

Medical treatment for reflux oesophagitis does not consistently improve asthma control: a systematic review.

BACKGROUND: A systematic literature review was conducted to assess the effect of treating reflux oesophagitis on asthma outcomes. METHODS: Randomised controlled trials of reflux oesophagitis treatment in adults or children that reported asthma health outcomes were included and assessed in accordance with the standard Cochrane systematic review process. Patients were typically adults with asthma and concurrent symptomatic gastro-oesophageal reflux who received interventions that included pharmacological therapy, conservative management, and surgery. The following outcome measures were assessed: lung function, peak expiratory flow, asthma symptoms, asthma medications, and nocturnal asthma. RESULTS: From 22 potentially relevant published and unpublished randomised controlled trials, 12 were included. Treatment duration ranged from 1 week to 6 months. Eight trials reported that treatment improved at least one asthma outcome, but these outcomes differed between trials. Overall, treatment of reflux oesophagitis did not consistently improve forced expiratory volume in one second (FEV(1)), peak expiratory flow rate, asthma symptoms, nocturnal asthma symptoms, or use of asthma medications in asthmatic subjects. Significant improvement in wheeze was reported in two studies. CONCLUSIONS: The published literature does not consistently support treatment of reflux oesophagitis as a means of controlling asthma. Further large randomised controlled trials in subjects with a demonstrated temporal relationship between gastro-oesophageal reflux and asthma are needed. These trials should be conducted over at least 6 months to allow adequate time to observe a treatment effect.

Adolescent↗
PubMed2001

Acute anti-inflammatory effects of inhaled budesonide in asthma: a randomized controlled trial.

Corticosteroids can have acute effects on airway function and methacholine airway responsiveness in asthma as early as 6 h after dosing, suggesting there may be an acute anti-inflammatory effect of inhaled corticosteroid in asthma. This study aimed to determine the effects of a single dose of inhaled budesonide on sputum eosinophils and mast cells in adults with asthma, and to examine whether the mechanism of clearance of eosinophils was by apoptosis. A randomized, double-blind, placebo-controlled, crossover study was conducted. At the screening visit, adults with stable asthma (n = 41) ceased inhaled corticosteroid therapy for 4 d and those with significant sputum eosinophilia (> or = 7%) were randomized (n = 26) to a single dose of budesonide 2,400 microg or placebo via Turbuhaler, on two separate study days. Symptoms and lung function were followed for 6 h, then sputum was induced and airway responsiveness to hypertonic saline determined. Sputum eosinophils (mean, SE) were significantly lower 6 h after budesonide (25%, 4.5), compared with placebo (37%, 6.2, p < 0.05). There was a 2.2-fold (95% CI 1.45 to 3.33) improvement in airway responsiveness with budesonide. No significant difference was seen on mast cells, apoptotic eosinophils, symptoms, or lung function. In conclusion, a single dose of inhaled corticosteroids has beneficial effects on airway inflammation and airway hyperresponsiveness as early as 6 h after dosing. This may be clinically useful as therapy during mild exacerbations of asthma.

Administration, Inhalation↗
PubMed2001

Heterogeneity of airway inflammation in persistent asthma : evidence of neutrophilic inflammation and increased sputum interleukin-8.

STUDY OBJECTIVES: To identify the characteristics of airway inflammation in persistent asthma and to examine the role of neutrophilic inflammation in noneosinophilic persistent asthma. METHODS: Nonsmoking adults (n = 56) with persistent asthma and healthy control subjects (n = 8) underwent hypertonic saline solution challenge and sputum induction. Selected sputum portions were dispersed with dithiothreitol and assayed for total cell count, cellular differential, supernatant eosinophil cationic protein (ECP), myeloperoxidase, and interleukin (IL)-8. RESULTS: We identified two distinct inflammatory patterns. Typical eosinophilic inflammation occurred in 41% of subjects, whereas the remainder exhibited noneosinophilic asthma (59%). Both neutrophil percentage and absolute neutrophil counts were increased in subjects with noneosinophilic asthma (64%, 283 x 10(6)/mL) compared to eosinophilic asthma (14%, 41 x 10(6)/mL) and control subjects (34%, 49 x 10(6)/mL; p = 0.0001). Myeloperoxidase was elevated in both noneosinophilic (280 ng/mL) and eosinophilic groups (254 ng/mL) compared with control subjects (82 ng/mL; p = 0.002). Sputum IL-8 levels were highest in subjects with noneosinophilic asthma (45 ng/mL) compared to eosinophilic asthma (9.6 ng/mL) and control subjects (3.5 ng/mL; p = 0.0001). Neutrophils correlated with IL-8 levels (r = 0.72). ECP was highest in subjects with eosinophilic asthma (2,685 ng/mL) compared with noneosinophilic asthma (1,081 ng/mL) and control subjects (110 ng/mL; p = 0.0001). CONCLUSION: Induced-sputum analysis in persistent asthma identifies two different inflammatory patterns. The most common pattern is noneosinophilic, associated with a neutrophil influx and activation, which may be mediated by IL-8 secretion. There is heterogeneity of airway inflammation in persistent asthma, which indicates differing mechanisms and may impact on treatment responses.

Adult↗
PubMed2001

[Eosinophilic airway diseases presenting with isolated cough except for asthma].

Cough variant asthma (CVA), atopic cough (AC) and eosinophilic bronchitis without asthma (EB) are eosinophilic airway diseases presenting with isolated chronic cough. Among them, bronchodilators are effective only in CVA. Bronchial responsiveness, diurnal variation of pulmonary function and bronchomotor tone are mildly increased to intermediate levels between mild asthma and normal in CVA, but not in AC or EB. Cough sensitivity is heightened in atopic cough and probably in EB, but not in CVA. Bronchoalveolar lavage eosinophilia is present in CVA and EB, but absent in AC. As asthma onset has been recognized in nearly 30% patients with CVA, but not in AC, long-term inhaled corticosteroid therapy is recommended only in CVA.

Adrenergic beta-2 Receptor Agonists↗
PubMed2001

Exacerbations of asthma: addressing the triggers and treatments.

Airway inflammation is known to play a crucial role in chronic asthma and has led to the effective use of anti-inflammatory treatments to control chronic asthma. Despite these improvements exacerbations of asthma continue to occur in subjects with stable disease compliant with treatment. Viral respiratory tract infections have been found to be associated with the majority of asthma exacerbations in both children and adults. Evidence is emerging that viral infections may alter the inflammatory infiltrate present in chronic asthma with a more heterogenous neutrophil/eosinophil infiltrate. The implications are that the pathogenesis of acute asthma may differ from that present in chronic asthma in important ways that may influence the effectiveness of treatment. Inhaled corticosteroids are effective in controlling chronic airway inflammation in asthma but appear not to be as effective in acute asthma. This may mean that new directions will be needed to target specifically the airway inflammation in virus-induced acute asthma.

Acute Disease↗