Prevalence of asthma, atopy, and bronchial hyperreactivity in bronchiectasis: a controlled study

Bronchiectasis in severe asthma and asthmatic components in bronchiectasis

Asthma and bronchiectasis are different diseases; however, differentiating them can be difficult because they share several symptomatic and physiological similarities. Approximately 20% of patients with bronchiectasis have eosinophilic inflammation, 34% show wheezing, and 7-46% have comorbid asthma, although comorbidity with severe asthma may be limited as shown in 3.3% of cases of bronchiectasis. Meanwhile, 25-68% of patients with severe asthma have comorbid bronchiectasis, and at least two phenotypes are present in the accompanying bronchiectasis: eosinophilic bronchiectasis and chronic infectious bronchiolitis/bronchiectasis. Recent studies show that type-2-targeted biologics are effective for eosinophilic bronchiectasis and theoretically effective for some of the remaining cases when used before oral corticosteroids. Further studies are needed to identify treatment strategies for severe asthma with comorbid bronchiectasis and vice versa.

Impact of asthma on bronchiectasis severity and risk of exacerbations

OBJECTIVE

Asthma is a frequent comorbidity of bronchiectasis, with possible implications for exacerbation and severity. We investigated the clinical impact of asthma on bronchiectasis in terms of disease severity and exacerbation risk.

METHODS

We collected demographic, clinical, and functional characteristics of patients with a confirmed diagnosis of bronchiectasis. All patients were investigated for concomitant diagnosis of asthma. The Bhalla score was used to assess radiological severity of bronchiectasis, and the Bronchiectasis Severity Index (BSI) was used to assess the clinical severity. Blood and sputum samples were collected to assess blood cell count, erythrocyte sedimentation rate, c-reactive protein, immunological status (IgA, IgE, IgM, IgG, and IgG subclasses), and microbiological analysis.

RESULTS

A total of 106 patients were enrolled in the study; 30.2% had concomitant asthma and were characterized by higher frequency of bronchiectasis exacerbation, despite higher Bhalla score and lower BSI compared to patients without asthma. Pseudomonas aeruginosa was more frequently isolated from the sputum of bronchiectasis patients without asthma. Total serum IgG, IgG1, and IgG3 were lower in patients with asthma. Blood eosinophils and exhaled nitric oxide were higher in patients with associated asthma. The presence of asthma and presence of Pseudomonas in sputum were the only significant determinants of frequent exacerbations in a binary logistic regression analysis.

CONCLUSION

The coexistence of asthma and bronchiectasis is associated with an independent increase in the risk of bronchiectasis exacerbation despite lower radiological and clinical severity indexes. Asthmatic airway inflammation could promote an enhanced "Cole's Cycle" that is responsible for a higher frequency of exacerbations.

How does comorbid bronchiectasis affect asthmatic patients? A meta-analysis

OBJECTIVE

Asthma and bronchiectasis are known to be two distinct diseases with different etiology, pathophysiology, management, and prognosis. However, a high prevalence of bronchiectasis has been reported in patients with severe asthma. Thus, it is of great importance to identify the impact of bronchiectasis on asthmatic patients.Data sources: Databases including PubMed, Embase, Cochrane, Web of Science were searched comprehensively to identify relevant human clinical studies published until February 2020.Study selections: Two investigators (Gelei Lan and Guochao Shi) independently obtained the potentially eligible articles based on their titles and abstracts. When opinions differed between the investigators, discussions were made to reach an agreement. The authors of the included studies were contacted for inquiry when necessary.

RESULTS

Six observational studies with 1004 patients were included in the meta-analysis. The mean prevalence of bronchiectasis in patients with asthma was 35.2% (ranging from 2.2% to 47%). Asthmatic patients with bronchiectasis were older, had a longer disease duration, exhibited greater severity, and showed more frequent exacerbations and hospitalization, and poorer lung function, compared with the patients without bronchiectasis.

CONCLUSION

Despite of the heterogeneity between included studies and detectable publication bias, this meta-analysis demonstrated the impact of comorbid bronchiectasis on asthmatic patients. Thus, coexistence of bronchiectasis should be considered a clinical phenotype of asthma, which may have associations with exacerbation and hospitalization.

Distinct "Immunoallertypes" of Disease and High Frequencies of Sensitization in Non-Cystic Fibrosis Bronchiectasis

RATIONALE

Allergic sensitization is associated with poor clinical outcomes in asthma, chronic obstructive pulmonary disease, and cystic fibrosis; however, its presence, frequency, and clinical significance in non-cystic fibrosis bronchiectasis remain unclear.

OBJECTIVES

To determine the frequency and geographic variability that exists in a sensitization pattern to common and specific allergens, including house dust mite and fungi, and to correlate such patterns to airway immune-inflammatory status and clinical outcomes in bronchiectasis.

METHODS

Patients with bronchiectasis were recruited in Asia (Singapore and Malaysia) and the United Kingdom (Scotland) (n = 238), forming the Cohort of Asian and Matched European Bronchiectasis, which matched recruited patients on age, sex, and bronchiectasis severity. Specific IgE response against a range of common allergens was determined, combined with airway immune-inflammatory status and correlated to clinical outcomes. Clinically relevant patient clusters, based on sensitization pattern and airway immune profiles ("immunoallertypes"), were determined.

MEASUREMENTS AND MAIN RESULTS

A high frequency of sensitization to multiple allergens was detected in bronchiectasis, exceeding that in a comparator cohort with allergic rhinitis (n = 149). Sensitization was associated with poor clinical outcomes, including decreased pulmonary function and more severe disease. "Sensitized bronchiectasis" was classified into two immunoallertypes: one fungal driven and proinflammatory, the other house dust mite driven and chemokine dominant, with the former demonstrating poorer clinical outcome.

CONCLUSIONS

Allergic sensitization occurs at high frequency in patients with bronchiectasis recruited from different global centers. Improving endophenotyping of sensitized bronchiectasis, a clinically significant state, and a "treatable trait" permits therapeutic intervention in appropriate patients, and may allow improved stratification in future bronchiectasis research and clinical trials.

An investigation into biomarkers for the diagnosis of ABPA and aspergillus disease in cystic fibrosis

BACKGROUND

Allergic bronchopulmonary aspergillosis (ABPA) is a hypersensitivity lung disease due to Aspergillus fumigatus (Af) which occurs in 10% of patients with cystic fibrosis (CF). ABPA is associated with increased morbidity and accelerated lung function decline; however, existing diagnostic criteria are nonspecific and diagnosis remains challenging. As ABPA is driven by Th2 inflammation, the aim of this study was to evaluate exhaled nitric oxide (FE _NO ), eosinophilic cationic protein (ECP), peripheral eosinophil count, and bronchodilator response (BDR) in patients with CF.

METHODS

A prospective observational cohort study of pediatric CF patients in a tertiary center. Patients had a clinical and serologic ABPA assessment, FE_NO , serum ECP, peripheral eosinophil count, and assessment of BDR. Patients were stratified into three groups; ABPA, Af sensitized (AFS), and non-ABPA non-Af-sensitized (non-AFS).

RESULTS

A total of 62 patients were included in the study: 13% ABPA, 19% AFS, and 68% non-AFS. Mean FE_NO was higher in the ABPA group at 37.8 ppb compared to AFS 15.1 ppb (P = .05) and non-AFS 13.7 ppb (P = .04). Mean peripheral eosinophil count in ABPA group was also higher at 1000 cells/uL, compared to AFS 221 cells/uL (P = .03) and non-AFS 220 cells/uL (P = .03). Mean BDR in ABPA group was 13% compared to 5.5% in non-AFS (P = .01). Serum ECP was higher in patients with ABPA positive compared to the other groups, although this was not statistically significant.

CONCLUSION

In children with cystic fibrosis, FE_NO and peripheral eosinophil counts are elevated in ABPA compared to those that are just sensitized to Aspergillus and may serve as useful diagnostic tests.

Prevalence of atopy and allergic rhinitis in patients with adult non-cystic fibrosis bronchiectasis

Background/aim

Non-cystic fibrosis bronchiectasis (non-CF BR) is common in developing countries.Limited data are available regarding the impact of atopy, and no data are available regarding allergic rhinitis in patients with adult bronchiectasis.The aim of this study was to evaluate the prevalence of atopy and allergic rhinitis in the clinical conditions of patients with BR.

Materials and methods

The study enrolled 101 patients who were diagnosed with non-CF BR using high-resolution computed chest tomography. Allergic rhinitis (AR) was defined by skin prick test (SPT) positivity and the presence of any nasal symptoms (watery runny nose, nasal obstruction, nasal itching, and sneezing).

Results

The mean age of patients was 48 ± 15 years (range 18–82); 55 (54.5%) patients were female. SPT positivity was detected in 37 (36.6%) cases. AR was detected in 32 (31.7%) patients with non-CF BR. AR was related to dyspnea (P = 0.04) and number of admissions to an emergency department in the previous year (P = 0.01). Forced expiratory volume in 1 s and forced vital capacity in patients with and without AR were different (P = 0.01 and P = 0.01, respectively). AR was correlated with number of admissions to an emergency department in the last year (r = 0.417, P = 0.005).

Conclusion

We concluded that atopy was detected in more than one-third of adult non-CF BR patients. This study demonstrated that non-CF BR patients might have AR; it might be important to be aware of nasal symptoms in non-CF BR patients.

A comprehensive approach to lung function in bronchiectasis

BACKGROUND

International guidelines recommend simple spirometry for bronchiectasis patients. However, pulmonary pathophysiology of bronchiectasis is very complex and still poorly understood. Our objective was to characterize lung function in bronchiectasis and identify specific functional sub-groups.

METHODS

This was a multicenter, prospective, observational study enrolling consecutive adults with bronchiectasis during stable sate. Patients underwent body-plethysmography before and after acute bronchodilation testing, diffusing lung capacity (DLCO) with a 3-year follow up. Air trapping and hyperinflation were a residual volume (RV) > 120%predicted and a total lung capacity>120%predicted. Acute reversibility was: ΔFEV1 ≥12% and 200 mL from baseline (FEV1rev) and ΔRV ≥10% reduction from baseline (RVrev). Sensitivity analyses included different reversibility cutoffs and excluded patients with concomitant asthma or chronic obstructive pulmonary disease.

RESULTS

187 patients were enrolled (median age: 68 years; 29.4% males). Pathophysiological abnormalities often overlapped and were distributed as follows: air trapping (70.2%), impaired DLCO (55.7%), airflow obstruction (41.1%), hyperinflation (15.7%) and restriction (8.0%). 9.7% of patients had normal lung function. RVrev (17.6%) was more frequent than FEV1rev (4.3%). Similar proportions were found after multiple sensitivity analyses. Compared with non-reversible patients, patients with RVrev had more severe obstruction (mean(SD) FEV1%pred: 83.0% (24.4) vs 68.9% (26.2); P = 0.02) and air trapping (RV%pred, 151.9% (26.6) vs 166.2% (39.9); P = 0.028).

CONCLUSIONS

Spirometry alone does not encompass the variety of pathophysiological characteristics in bronchiectasis. Air trapping and diffusion impairment, not airflow obstruction, represent the most common functional abnormalities. RVrev is related to worse lung function and might be considered in bronchiectasis' workup and for patients' functional stratification.

Bronchiectasis in severe asthma: Clinical features and outcomes

BACKGROUND

Bronchiectasis is increasingly being identified in patients with severe asthma and could contribute to disease severity.

OBJECTIVE

To determine the prevalence of bronchiectasis in a population of patients with severe asthma and to better characterize the clinical features of these patients and their outcomes.

METHODS

We retrospectively reviewed the medical files of 184 subjects with confirmed severe asthma who had undergone high-resolution thoracic computed tomography and compared the characteristics and outcomes of subjects with and without bronchiectasis.

RESULTS

Bronchiectasis was identified in 86 patients (47%). These patients had concomitant hypersensitivity to nonsteroidal anti-inflammatory drugs (odds ratio [OR] 2.24, 95% confidence interval [CI] 1.00-5.03) and gastroesophageal reflux disease (OR 1.89, 95% CI 1.05-3.41) more frequently than subjects without bronchiectasis, but had less atopic dermatitis (OR 0.188, 95% CI 0.04-0.88). Subjects with bronchiectasis were more frequently hospitalized for asthma exacerbations (OR 2.09, 95% CI 1.08-4.05) and had higher blood eosinophil levels (464 vs 338; P = .005) than subjects without bronchiectasis.

CONCLUSION

Our study suggests that in subjects with severe asthma, the presence of bronchiectasis is associated with more frequent hospitalizations, concomitant gastroesophageal reflux disease, hypersensitivity to nonsteroidal anti-inflammatory drugs, and higher blood eosinophil counts. Bronchiectasis could represent an additional phenotypic feature of severe eosinophilic asthma.

Effects of long-term bronchodilators in bronchiectasis patients with airflow limitation based on bronchodilator response at baseline

Purpose

The association between positive bronchodilator response (BDR) at baseline and the effect of long-term bronchodilator therapy has not been well elucidated in patients with bronchiectasis. The aims of our study were to explore the association between positive BDR at baseline and lung-function improvement following long-term (3–12 months) bronchodilator therapy in bronchiectasis patients with airflow limitation.

Materials and methods

The medical records of 166 patients with clinically stable bronchiectasis who underwent baseline pre- and postbronchodilator spirometry and repeated spirometry after 3–12 months of bronchodilator therapy were retrospectively reviewed. For analysis, patients were divided into two groups, responders and poor responders, based on achievement of at least 12% and 200 mL in forced expiratory volume in 1 second (FEV₁) following bronchodilator therapy from baseline FEV₁.

Results

A total of 57 patients (34.3%) were responders. These patients were more likely to have positive BDR at baseline than poor responders (38.6% [22 of 57] vs 18.3% [20 of 109], P=0.004). This association persisted after adjustment for other confounding factors (adjusted odds ratio 2.298, P=0.034). However, we found FEV₁ improved significantly following long-term bronchodilator therapy, even in patients without positive BDR at baseline (change in FEV₁ 130 mL, interquartile range −10 to 250 mL; P<0.001).

Conclusion

Positive BDR at baseline was independently associated with responsiveness to long-term bronchodilator therapy in bronchiectasis patients with airflow limitation. However, FEV₁ improvement was also evident in bronchiectasis patients without positive BDR at baseline, suggesting that these patients can benefit from long-term bronchodilator therapy.

Asthma and bronchiectasis exacerbation

Bronchiectasis and asthma are common respiratory diseases worldwide. However, the influence of asthma on bronchiectasis remains unclear. The objective of this study is to analyse the effects of asthma on bronchiectasis exacerbation.Data from inpatients diagnosed with bronchiectasis with or without asthma at Shanghai Pulmonary Hospital (Shanghai, China) between January 2013 and December 2014 were retrospectively collected and analysed. 249 patients with only bronchiectasis and 214 patients with both bronchiectasis and asthma were included in the study. Follow-up records were used to evaluate the effect of asthma on bronchiectasis exacerbation.The variables found to be independently associated with bronchiectasis exacerbations were age (OR 1.07, 95% CI 1.03-1.11; p<0.001), duration of symptoms (OR 1.06, 95% CI 1.03-1.09; p<0.001), the presence of asthma (OR 2.6, 95% CI 1.15-5.88; p=0.021), forced expiratory volume in 1 s <50% predicted (OR 4.03, 95% CI 1.75-9.26; p=0.001), isolation of Pseudomonas aeruginosa in sputum (OR 2.41, 95% CI 1.00-5.79; p=0.05) and lung lesion extension to more than two lobes (OR 2.73, 95% CI 1.16-6.45; p=0.022).The existence of asthma was associated with an independent increase in risk of bronchiectasis exacerbation.

The effects of bronchiectasis on asthma exacerbation

BACKGROUND

Bronchiectasis and asthma are different in many respects, but some patients have both conditions. Studies assessing the effect of bronchiectasis on asthma exacerbation are rare. The aim of this study is to investigate the effect of bronchiectasis on asthma exacerbation.

METHODS

We enrolled 2,270 asthma patients who were followed up in our hospital. Fifty patients had bronchiectasis and asthma. We selected fifty age- and sex-matched controls from the 2,220 asthma patients without bronchiectasis, and assessed asthma exacerbation and its severity based on the annual incidence of total asthma exacerbation, annual prevalence of steroid use, and frequency of emergency room visits and hospitalizations due to asthma exacerbation in each group.

RESULTS

Fifty patients (2.2%) had bronchiectasis and asthma. The annual incidence of asthma exacerbation was higher in patients with asthma and bronchiectasis than in patients with asthma alone (1.08±1.68 vs. 0.35±0.42, p=0.004). The annual prevalence of steroid use (0.9±1.54 vs. 0.26±0.36, p=0.006) and the frequency of emergency room visits (0.46±0.84 vs. 0.02±0.13, p=0.001) due to asthma exacerbation were also higher in patients with asthma and bronchiectasis than in patients with asthma alone.

CONCLUSION

Bronchiectasis is associated with difficult asthma control.

Distinguishing adult-onset asthma from COPD: a review and a new approach

Adult-onset asthma and chronic obstructive pulmonary disease (COPD) are major public health burdens. This review presents a comprehensive synopsis of their epidemiology, pathophysiology, and clinical presentations; describes how they can be distinguished; and considers both established and proposed new approaches to their management. Both adult-onset asthma and COPD are complex diseases arising from gene-environment interactions. Early life exposures such as childhood infections, smoke, obesity, and allergy influence adult-onset asthma. While the established environmental risk factors for COPD are adult tobacco and biomass smoke, there is emerging evidence that some childhood exposures such as maternal smoking and infections may cause COPD. Asthma has been characterized predominantly by Type 2 helper T cell (Th2) cytokine-mediated eosinophilic airway inflammation associated with airway hyperresponsiveness. In established COPD, the inflammatory cell infiltrate in small airways comprises predominantly neutrophils and cytotoxic T cells (CD8 positive lymphocytes). Parenchymal destruction (emphysema) in COPD is associated with loss of lung tissue elasticity, and small airways collapse during exhalation. The precise definition of chronic airflow limitation is affected by age; a fixed cut-off of forced expiratory volume in 1 second/forced vital capacity leads to overdiagnosis of COPD in the elderly. Traditional approaches to distinguishing between asthma and COPD have highlighted age of onset, variability of symptoms, reversibility of airflow limitation, and atopy. Each of these is associated with error due to overlap and convergence of clinical characteristics. The management of chronic stable asthma and COPD is similarly convergent. New approaches to the management of obstructive airway diseases in adults have been proposed based on inflammometry and also multidimensional assessment, which focuses on the four domains of the airways, comorbidity, self-management, and risk factors. Short-acting beta-agonists provide effective symptom relief in airway diseases. Inhalers combining a long-acting beta-agonist and corticosteroid are now widely used for both asthma and COPD. Written action plans are a cornerstone of asthma management although evidence for self-management in COPD is less compelling. The current management of chronic asthma in adults is based on achieving and maintaining control through step-up and step-down approaches, but further trials of back-titration in COPD are required before a similar approach can be endorsed. Long-acting inhaled anticholinergic medications are particularly useful in COPD. Other distinctive features of management include pulmonary rehabilitation, home oxygen, and end of life care.

Combination inhaled corticosteroids and long-acting beta2-agonists for children and adults with bronchiectasis

BACKGROUND

Bronchiectasis is a major contributor to chronic respiratory morbidity and mortality worldwide. Wheeze and other asthma-like symptoms and bronchial hyperreactivity may occur in people with bronchiectasis. Physicians often use asthma treatments in patients with bronchiectasis.

OBJECTIVES

To assess the effects of inhaled long-acting beta2-agonists (LABA) combined with inhaled corticosteroids (ICS) in children and adults with bronchiectasis during (1) acute exacerbations and (2) stable state.

SEARCH METHODS

The Cochrane Airways Group searched the the Cochrane Airways Group Specialised Register of Trials, which includes records identified from the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and other databases. The Cochrane Airways Group performed the latest searches in October 2013.

SELECTION CRITERIA

All randomised controlled trials (RCTs) of combined ICS and LABA compared with a control (placebo, no treatment, ICS as monotherapy) in children and adults with bronchiectasis not related to cystic fibrosis (CF).

DATA COLLECTION AND ANALYSIS

Two review authors extracted data independently using standard methodological procedures as expected by The Cochrane Collaboration.

MAIN RESULTS

We found no RCTs comparing ICS and LABA combination with either placebo or usual care. We included one RCT that compared combined ICS and LABA with high-dose ICS in 40 adults with non-CF bronchiectasis without co-existent asthma. All participants received three months of high-dose budesonide dipropionate treatment (1600 micrograms). After three months, participants were randomly assigned to receive either high-dose budesonide dipropionate (1600 micrograms per day) or a combination of budesonide with formoterol (640 micrograms of budesonide and 18 micrograms of formoterol) for three months. The study was not blinded. We assessed it to be an RCT with overall high risk of bias. Data analysed in this review showed that those who received combined ICS-LABA (in stable state) had a significantly better transition dyspnoea index (mean difference (MD) 1.29, 95% confidence interval (CI) 0.40 to 2.18) and cough-free days (MD 12.30, 95% CI 2.38 to 22.2) compared with those receiving ICS after three months of treatment. No significant difference was noted between groups in quality of life (MD -4.57, 95% CI -12.38 to 3.24), number of hospitalisations (odds ratio (OR) 0.26, 95% CI 0.02 to 2.79) or lung function (forced expiratory volume in one second (FEV1) and forced vital capacity (FVC)). Investigators reported 37 adverse events in the ICS group versus 12 events in the ICS-LABA group but did not mention the number of individuals experiencing adverse events. Hence differences between groups were not included in the analyses. We assessed the overall evidence to be low quality.

AUTHORS' CONCLUSIONS

In adults with bronchiectasis without co-existent asthma, during stable state, a small single trial with a high risk of bias suggests that combined ICS-LABA may improve dyspnoea and increase cough-free days in comparison with high-dose ICS. No data are provided for or against, the use of combined ICS-LABA in adults with bronchiectasis during an acute exacerbation, or in children with bronchiectasis in a stable or acute state. The absence of high quality evidence means that decisions to use or discontinue combined ICS-LABA in people with bronchiectasis may need to take account of the presence or absence of co-existing airway hyper-responsiveness and consideration of adverse events associated with combined ICS-LABA.

Asthma-like peak flow variability in various lung diseases

BACKGROUND AND OBJECTIVES

Bronchodilator reversibility and diurnal peak flow variability are considered characteristic of asthma patients. Patients with chronic obstructive pulmonary disease (COPD) show poor reversibility. But reversibility and variability in other pulmonary diseases manifesting with airflow obstruction in not known. Therefore, we assessed reversibility and peak flow variability in patients with various lung diseases to recognize the pattern.

MATERIALS AND METHODS

Seventy consecutive patients with a diagnosis of lung diseases manifesting with airflow obstruction were recruited in the study. These included 23 patients with asthma, 11 patients with bronchiectasis, 16 patients with post-tubercular lung disease (PTLD), and 20 patients with COPD. Ten healthy matched control subjects were also selected to pair with asthmatic patients. Bronchodilator reversibility test was done initially and peak expiratory flow rate (PEFR) was measured for a duration of 1 week by patients themselves on a chart that was given to them. The mean amplitude percentage of these records were analyzed.

RESULTS

The mean values of peak flow variability were 14.73% ± 6.1% in asthmatic patients, 11.98% ± 7.5% in patients with bronchiectasis, and 10.54% ± 5.3% in PTLD. The difference in the mean values of peak flow variability between asthma and bronchiectasis, that is, 14.73 (6.1) vs 11.98 (7.5) was not statistically significant (P > 0.05). Forced expiratory volume one second (FEV(1)) reversibility values were 14.77% ± 26.93%, 11.24% ± 20.43%, 10.85% ± 13.02%, 16.83% ± 22.84%, and 5.47% ± 4.99% in asthma, COPD, PTLD, bronchiectasis, and healthy subjects, respectively.

CONCLUSION

Both reversibility and diurnal peak flow variability were higher in patients with various lung diseases compared with normal healthy subjects. Although these are characteristic of asthma, some cases of bronchiectasis and PTLD patients may also manifest asthma-like PEFR variability and reversibility.

[Treatment of non-cystic fibrosis bronchiectasis]

Bronchiectasis is currently growing in importance due to both the increase in the number of diagnoses made as well as the negative impact that its presence has on the baseline disease that generates it. A fundamental aspect in these patients is the colonization and infection of the bronchial mucous by potentially pathogenic microorganisms (PPM), which are the cause in most cases of the start of the chronic inflammatory process that results in the destruction and dilatation of the bronchial tree that is characteristic in these patients. The treatment of the colonization and chronic bronchial infection in these patients should be based on prolonged antibiotic therapy in its different presentations. Lately, the inhaled form is becoming especially prominent due to its high efficacy and limited production of important adverse effects. However, one must not overlook the fact that the management of patients with bronchiectasis should be multidisciplinary and multidimensional. In addition to antibiotic treatment, the collaboration of different medical and surgical specialties is essential for the management of the exacerbations, nutritional aspects, respiratory physiotherapy, muscle rehabilitation, complications, inflammation and bronchial hyperreactivity and the hypersecretion that characterizes these patients.

Pathogenesis of bronchiectasis

Non-cystic fibrosis bronchiectasis is a heterogeneous condition and its pathogenesis is still not well defined. A combination of a defect in host defense and bacterial infection allows microbial colonization of the airways resulting in chronic inflammation and lung damage. An ongoing cycle of infection and inflammation may be established. Typically, the walls of the small airway are infiltrated by inflammatory cells causing obstruction whilst mediators, such as proteases released predominantly by neutrophils, damage the large airways resulting in bronchial dilatation. Adjacent parenchyma is also involved in the inflammation. Lung function testing generally demonstrates mild to moderate airflow obstruction that progresses over time. There are a large number of different aetiologic factors associated with bronchiectasis. A variety of different microbial pathogens is involved and they change as disease progresses.

The pathophysiology of bronchiectasis

Bronchiectasis is defined by permanent and abnormal widening of the bronchi. This process occurs in the context of chronic airway infection and inflammation. It is usually diagnosed using computed tomography scanning to visualize the larger bronchi. Bronchiectasis is also characterized by mild to moderate airflow obstruction. This review will describe the pathophysiology of noncystic fibrosis bronchiectasis. Studies have demonstrated that the small airways in bronchiectasis are obstructed from an inflammatory infiltrate in the wall. As most of the bronchial tree is composed of small airways, the net effect is obstruction. The bronchial wall is typically thickened by an inflammatory infiltrate of lymphocytes and macrophages which may form lymphoid follicles. It has recently been demonstrated that patients with bronchiectasis have a progressive decline in lung function. There are a large number of etiologic risk factors associated with bronchiectasis. As there is generally a long-term retrospective history, it may be difficult to determine the exact role of such factors in the pathogenesis. Extremes of age and smoking/chronic obstructive pulmonary disease may be important considerations. There are a variety of different pathogens involved in bronchiectasis, but a common finding despite the presence of purulent sputum is failure to identify any pathogenic microorganisms. The bacterial flora appears to change with progression of disease.

Interpretation of the "positive" methacholine challenge

BACKGROUND

A methacholine challenge may be used in confirming the diagnosis of asthma, occupational asthma, or reactive airways dysfunction syndrome (RADS) through identification of bronchial hyperreactivity (BHR). While sensitivity of the test in diagnosing clinically significant asthma is excellent, specificity of the test is poor. Since there are many conditions which have been associated with BHR, a positive test must be interpreted cautiously.

METHODS

This paper reviews potential causes of a positive methacholine challenge other than asthma or RADS which have been reported in the medical literature.

RESULTS

Factors which may be associated with a positive methacholine test include test methodology, normal variation of BHR in the general population, and numerous medical conditions.

CONCLUSIONS

In cases of inhalation exposure evaluations, alternative explanations must be considered when determining whether a causal association exists between the exposure and a positive methacholine test result.

The impact of bronchiectasis in clinical presentation of asthma

BACKGROUND

Though asthma and bronchiectasis are two different diseases, their coexistence has been shown in many patients. The aim of this study was to evaluate the clinical features of asthmatics with bronchiectasis compared with pure asthmatics.

METHODS

We evaluated 1680 asthmatics followed-up in our clinic. Fifty-one asthmatics had the diagnosis of bronchiectasis. These patients were compared with fifty-one age and gender matched asthmatics without bronchiectasis.

RESULTS

The prevalence of bronchiectasis among the asthmatics was 3%. Asthma diagnosis was made at the age of 33.2 +/- 16.8 years for asthmatics with bronchiectasis and 39.5 +/- 16.2 years for pure asthmatics (P = 0.05). Asthmatics with bronchiectasis mostly had severe persistent asthma (49.0%), while pure asthmatics mostly had mild persistent and intermittent asthma (69.4%). History of hospitalization due to severe asthma exacerbation and presence of chronic respiratory failure was significantly higher in bronchiectatic group.

CONCLUSIONS

These data show that bronchiectasis can contribute to severe and difficult to control asthma with pulmonary complications like chronic respiratory failure.

Is there a role for inhaled corticosteroids and macrolide therapy in bronchiectasis?

Bronchiectasis is characterised by permanent dilatation of the bronchi that arises from chronic inflammation predominantly caused by bacterial infection. This condition remains a major cause of excess respiratory morbidity and treatment is generally only partly successful. There is an urgent need for improved anti-inflammatory medication to treat bronchiectasis. Two potentially useful therapies are inhaled corticosteroids (ICS) and macrolides. The clinical trials that have been performed in bronchiectasis with these two medications can be considered to be preliminary data. This article reviews the anti-inflammatory properties, clinical efficacy and adverse effects of ICS and macrolides.ICS have a large number of potent anti-inflammatory properties. ICS remain the first-line treatment in asthma, reduce exacerbations in chronic obstructive pulmonary disease, and may improve lung function and symptoms in cystic fibrosis (CF). Four small clinical trials have assessed the effect of high-dose ICS on bronchiectasis. The main reported effect of these trials was a reduction in sputum volume and this may be a marker of decreased airway inflammation. Other possible benefits included decreased cough and sputum inflammatory cells/biomarkers. ICS have a relatively high prevalence of local adverse effects, and may be associated with ocular complications and osteoporosis. These adverse effects can be minimised by prescribing low doses of the medication. Macrolides have both antibacterial and immunomodulatory properties. Macrolides have less marked immunosuppressive properties than corticosteroids, and effects include decreasing mucous production, inhibiting virulence factors and biofilm formation of Pseudomonas aeruginosa, decreasing leukocyte numbers and altering inflammatory mediator release. Macrolides have been shown to be extremely effective in the treatment of diffuse panbronchiolitis, improve lung function and symptoms in asthma and CF, and reduce nasal polyps and secretions in sinusitis. Five small clinical trials have assessed the effect of macrolides on bronchiectasis. Reported benefits include reduced sputum volume, improved lung function and better symptom control. Macrolides are generally well tolerated, although they do have a number of drug interactions. There are concerns about the development of resistance, especially to non-tuberculous mycobacteria, with prolonged macrolide use. The evidence available suggests that both medications have a role in the management of bronchiectasis. More definitive trials of ICS and macrolides in bronchiectasis will clarify the likely benefit of these therapies.

Bronchiectasis

Bronchiectasis is generally classified into cystic fibrosis and non-cystic fibrosis bronchiectasis. This review article describes non-cystic fibrosis bronchiectasis in adults. Bronchiectasis can be considered a heterogeneous condition characterized by irreversible airway dilatation with chronic bronchial infection/inflammation. It remains a common condition and is a major cause of respiratory morbidity. Many factors are associated with bronchiectasis, but most commonly patients will have idiopathic disease. Important clinical findings include chronic productive cough, rhinosinusitis, fatigue and bi-basal crackles. Patients have usually had symptoms for many years. Diagnosis is confirmed by high-resolution computed tomography scanning using standardized criteria. Spirometry shows moderate airflow obstruction and there is a high prevalence of bronchial hyperreactivity. The most common pathogens are non-typeable Haemophilus influenzae and Pseudomonas aeruginosa. There may be considerable overlap with other chronic airway diseases. Treatment regimens are still not well defined. Patients tend to have ongoing symptoms and decline in respiratory function despite treatment.

Atopy in Patients with Bronchiectasis: More than Coincidence

Bronchiectasis is common in developing countries, but its precise underlying mechanism can be detected in only about 40% of the cases. The studies reporting the frequency of atopy and its relation to radiological findings and lung function in bronchiectasis are limited in number, and the results are controversial. The present study was designed to investigate the relationship between atopy and bronchiectasis by means of high resolution computed tomography (HRCT) and pulmonary function tests. Skin prick test, HRCT and pulmonary function tests, including spirometric values of forced expiratory volume in one second (FEV1), FEV1/FVC (forced vital capacity) ratio were performed in 121 bronchiectatic patients of unknown etiology and in 68 healthy controls. Atopy and HRCT scores for the severity of atopy and extent of bronchiectasis respectively were determined for each patient. The rate of atopy (48.8% vs 11.8%) and mean atopy score (14.3 +/- 10.1 mm vs 5.5 +/- 2.1 mm) were significantly higher in patients with bronchiectasis than those in controls. Atopic patients had significantly worse spirometric values and more extended bronchiectasis than non-atopics. There is a significant correlation between atopy and HRCT scores (r = 0.54, p < 0.001), indicating that the more severe atopy is the more extended bronchiectasis. In conclusion, we suggest that the rate of atopy is higher in bronchiectatic patients than that in healthy controls. Bronchiectatic patients with atopy have lower spirometric values and higher HRCT scores. Atopy might be considered as a deteriorating and/or a causative or contributing factor for development of bronchiectasis.

Associations between bronchial hyperresponsiveness and immune cell parameters in patients with chronic fatigue syndrome

STUDY OBJECTIVE

To examine whether bronchial hyperresponsiveness (BHR) in patients with chronic fatigue syndrome (CFS) is caused by immune system abnormalities.

DESIGN

Prospective comparative study.

SETTING

A university-based outpatient clinic (Vrije Universiteit; Brussels, Belgium).

PARTICIPANTS

One hundred thirty-seven CFS patients and 27 healthy volunteers.

MEASUREMENTS

Pulmonary function testing, histamine bronchoprovocation test, immunophenotyping, and ribonuclease (RNase) latent determination.

RESULTS

Seventy-three of 137 patients presented with BHR, of whom 64 had normal results of the histamine bronchoprovocation test. No significant differences were found in age or sex characteristics between the groups. There were no differences in the RNase L ratio, total lung capacity, or FEV(1)/FVC ratio between CFS patients with or without BHR. The group of patients in whom BHR was present (BHR+) differs most significantly from the control group with eight differences in the immunophenotype profile in the cell count analysis and seven differences in the percentage distribution profile. The group of patients in whom no BHR was detected (BHR-) only differed from the control subjects in CD25+ count and in the percentage of CD25+ cells. We observed a significant increase in cytotoxic T-cell count and in the percentage of BHR+ patients compared to BHR- patients, which is consistent with the significant reduction in percentage naïve T cells.

CONCLUSIONS

These results refute any association between the cleaving of 80 kd RNase L and BHR. Immunophenotyping of our sample confirmed earlier reports on (chronic) immune activation in patients with CFS, compared to healthy control subjects. BHR+ CFS patients have more evidence of immune activation compared to BHR- patients. Inflammation and the consequent IgE-mediated activation of mast cells and eosinophils, as seen in asthma patients, is unlikely to be responsible for the presence of BHR in patients with CFS.

Evolving concepts on the value of adenosine hyperresponsiveness in asthma and chronic obstructive pulmonary disease

Adenosine is a purine nucleoside which mediates a variety of cellular responses relevant to asthma and COPD through interaction with specific receptors. Administration of adenosine by inhalation to patients with asthma and COPD is known to cause concentration related bronchoconstriction. Responses elicited by this purine derivative in asthma and COPD should not be considered as a mere reflection of non-specific airways hyperresponsiveness. Evaluation of airways responsiveness by adenosine induced bronchoconstriction may be valuable in differentiating asthma from COPD, monitoring of anti-inflammatory treatment in asthma, surveying disease progression, and assessing disease activity in relation to allergic airways inflammation.

Bronchiectasis: still a problem

The prevalence of bronchiectasis (BR) has decreased significantly in industrialized countries, but is still commonplace in developing countries. We evaluated the causes and clinical features of BR in 23 children (13 boys (57%) and 10 girls (43%), with a mean age of 8.45 +/- 4.02 years). Infection was the major cause of BR in our region. In 8 patients, BR developed after tuberculosis or pneumonia, was associated with immune deficiency syndromes in 4 children, and with asthma in 4. Cystic fibrosis was diagnosed in 4 cases and ciliary dyskinesia in 3. In 10 patients, only one lobe was involved. Bronchiectatic lesions were most commonly found in the left lower lobe and were observed in 7 patients. Multilobar involvement was found in 13 patients. The initial treatment was primarily medical, but in 2 patients whose medical therapy failed, pulmonary resection was carried out. Three patients died from severe pulmonary infection and respiratory failure.

Airflow obstruction in bronchiectasis: correlation between computed tomography features and pulmonary function tests

BACKGROUND

An obstructive defect is usual in bronchiectasis, but the pathophysiological basis of airflow obstruction remains uncertain. High resolution computed tomographic (CT) scanning now allows quantitation of static morphological abnormalities, as well as dynamic changes shown on expiratory CT scans. The aim of this study was to determine which static and dynamic structural abnormalities on the CT scan are associated with airflow obstruction in bronchiectasis.

METHODS

The inspiratory and expiratory features on the CT scan of 100 patients with bronchiectasis undergoing concurrent lung function tests were scored semi-quantitatively by three observers.

RESULTS

On univariate analysis the extent and severity of bronchiectasis, the severity of bronchial wall thickening, and the extent of decreased attenuation on the expiratory CT scan correlated strongly with the severity of airflow obstruction; the closest relationship was seen between decreased forced expiratory volume in one second (FEV(1)) and the extent of decreased attenuation on the expiratory CT scan (R(s) = -0.55, p<0. 00005). On multivariate analysis bronchial wall thickness and decreased attenuation were consistently the strongest independent determinants of airflow obstruction. The extent of decreased attenuation was positively associated with the severity of bronchial wall thickness, but was not independently linked to gas transfer levels. Endobronchial secretions seen on CT scanning had no functional significance; the severity of bronchial dilatation was negatively associated with airflow obstruction after adjustment for other morphological features.

CONCLUSIONS

These findings indicate that airflow obstruction in bronchiectasis is primarily linked to evidence of intrinsic disease of small and medium airways on CT scanning and not to bronchiectatic abnormalities in large airways, emphysema, or retained endobronchial secretions.

Different airway responsiveness profiles in atopic asthma, nonatopic asthma, and Sjögren's syndrome. BHR Study Group. Bronchial hyperresponsiveness

BACKGROUND

Different mechanisms may underlie bronchial hyperresponsiveness (BHR) in different diseases. The aim of this study was to investigate the bronchial responsiveness profile produced by three different challenge tests, methacholine, a direct stimulus, and two indirect stimuli, adenosine 5'-monophosphate (AMP) and cold air, in subjects with asthma and patients with Sjögren's syndrome.

METHODS

The study population comprised 40 adult patients with asthma, 18 subjects with Sjögren's syndrome, and 20 controls. Blood samples were collected before each challenge for measurements of serum eosinophil peroxidase (S-EPO) and eosinophil cationic protein (S-ECP). The investigated subjects recorded peak expiratory flow and kept a symptom diary.

RESULTS

Atopic subjects with asthma were significantly more hyperresponsive to AMP than nonatopic subjects with asthma (P=0.01) and subjects with Sjögren's syndrome (P=0.02). No difference was seen between atopic and nonatopic subjects with asthma in the case of challenges with methacholine or cold air. In atopic subjects with asthma, a significant correlation was found between challenges with methacholine and AMP (r=0.91, P=0.0001) and methacholine and cold air (r=0.83, P=0.004), but, in nonatopic subjects with asthma, no significant correlation was seen between methacholine and AMP or cold air challenges. In atopic subjects with asthma, the dose-response slope for AMP was correlated to S-EPO (r= -0.56; P = 0.01) and S-ECP (r= -0.51, P = 0.02), while no correlation between BHR and inflammation markers was found in the two other patient groups.

CONCLUSIONS

The results of this study suggest that patients with asthma and subjects with Sjögren's syndrome display different bronchial responsiveness profiles for different challenge agents. Atopic subjects with asthma are more hyperresponsive to AMP than nonatopic subjects and patients with Sjögren's syndrome. More than one challenge may be required to detect different aspects of bronchial responsiveness.

The effect of regular salbutamol on lung function and bronchial responsiveness in patients with primary ciliary dyskinesia

STUDY OBJECTIVE

There is growing evidence that regular beta(2)-agonist use in patients with asthma is associated with decreased airway caliber and increased bronchial responsiveness. The aim of this study was to determine whether regular treatment with beta(2)-agonists induces changes in lung function and bronchial responsiveness in patients with primary ciliary dyskinesia.

DESIGN

A randomized, double-blind, placebo-controlled, crossover study.

PATIENTS

Nineteen children with primary ciliary dyskinesia.

INTERVENTIONS

Subjects received inhaled salbutamol or identical placebo (2 x 100 microg qid) for periods of 6 weeks with a wash-out period of 4 weeks.

MEASUREMENTS AND RESULTS

FEV(1) was measured before and 3 weeks and 6 weeks after salbutamol or placebo treatment. High-dose methacholine inhalation tests were performed before and 6 weeks after each treatment. The provocative concentration of methacholine producing a 20% fall in FEV(1) (PC(20)) and maximal airway narrowing (MDeltaFFEV(1)) was measured. No significant change in FEV(1) was observed during the salbutamol or placebo periods. No significant differences in the parameters of bronchial responsiveness (PC(20) and MDeltaFFEV(1)) were noted as the result of either salbutamol or placebo treatment.

CONCLUSION

Our data have shown that salbutamol, inhaled regularly for 6 weeks, did not cause either a decline in lung function or an increase in bronchial responsiveness in subjects with primary ciliary dyskinesia.

Bronchodilator response to inhaled beta-2 agonist and anticholinergic drugs in patients with bronchiectasis

OBJECTIVE

An increase in incidence of reversible airflow obstruction and bronchial hyperresponsiveness occurs in patients with bronchiectasis. We conducted a study to assess the efficacy of bronchodilators in the treatment of bronchiectasis.

METHODOLOGY

Twenty-four patients with confirmed bronchiectasis were studied. Each patient inhaled fenoterol 400 microg administered by metered dose inhaler via a spacer after a baseline lung function and a lung function test was repeated 30 min later. This was followed by a second dose of fenoterol 5 mg via nebulizer and another lung function test 30 min later. A repeat study was done at least 24 h later with ipratropium bromide 40 microg by metered dose inhaler and 500 microg by a nebulizer.

RESULTS

The results showed a significant improvement from baselines (mean percentage change +/- SD) of peak expiratory flow rate (PEF) by 8.5 +/- 8.72% and 15.3 +/- 11.63%, forced expiratory volume in 1 s (FEV1) by 8.77 +/- 9.69% and 10.2 +/- 12.2% and forced vital capacity (FVC) by 10.25 +/- 11.61% and 10.09 +/- 10.88% after low- and high-dose fenoterol, respectively. The improvements after low- and high-dose ipratropium bromide for PEE FEV1 and FVC were 9.89 +/- 9.35% and 14.39 +/- 12.82%, 9.38 +/- 10.41% and 13.52 +/- 17.09%, and 8.03 +/- 10.85% and 9.63 +/- 13.85%, respectively. Eleven patients (45.8%) responded to one or both bronchodilators significantly (> 15% improvement in FEV1). Five patients (20%) responded to both, three (12%) to fenoterol alone and another three (12%) to ipratropium bromide alone.

CONCLUSION

There is significant bronchodilator response in a subset of patients with bronchiectasis and patients with bronchiectasis should therefore undergo bronchodilator testing. Skin prick testing against a panel of nine allergens done on each individual yielded a positive result in 13 patients (54.2%).

Links between hospital diagnoses of bronchiectasis and asthma

In view of the conflicting notions of the relationship between bronchiectasis and asthma, we have analysed the use of hospital services by bronchiectasis and asthma patients and evaluated the links between these diseases, employing data from the Finnish Hospital Discharge Register of over 21 million hospitalization periods recorded in 1972-92. We conclude that asthma is common in hospitalized bronchiectasis patients and appears to be consequent upon this disease.

Targeted expression of IL-11 in the murine airway causes lymphocytic inflammation, bronchial remodeling, and airways obstruction

Interleukin-11 is a pleotropic cytokine produced by lung stromal cells in response to respiratory viruses, cytokines, and histamine. To further define its potential effector functions, the Clara cell 10-kD protein promoter was used to express IL-11 and the airways of the resulting transgene mice were characterized. In contrast to transgene (-) littermates, the airways of IL-11 transgene (+) animals manifest nodular peribronchiolar mononuclear cell infiltrates and impressive airways remodeling with subepithelial fibrosis. The inflammatory foci contained large numbers of B220(+) and MHC Class II(+) cells and lesser numbers of CD3(+), CD4(+), and CD8(+) cells. The fibrotic response contained increased amounts of types III and I collagen, increased numbers of alpha smooth muscle actin and desmin-containing cells and a spectrum of stromal elements including fibroblasts, myofibroblasts, and smooth muscle cells. Physiologic evaluation also demonstrated that 2-mo-old transgene (+) mice had increased airways resistance and non-specific airways hyperresponsiveness to methacholine when compared with their transgene (-) littermates. These studies demonstrate that the targeted expression of IL-11 in the mouse airway causes a B and T cell-predominant inflammatory response, airway remodeling with increased types III and I collagen, the local accumulation of fibroblasts, myofibroblasts, and myocytes, and obstructive physiologic dysregulation. IL-11 may play an important role in the inflammatory and fibrotic responses in viral and/or nonviral human airway disorders.

Bronchiectasis: a neglected cause of respiratory morbidity and mortality

Bronchiectasis is a progressive condition characterized by irreversible destruction and dilation of airways generally associated with chronic bacterial infections. Although in Western countries, the morbidity and mortality from bronchiectasis is considered to have declined markedly in the modern era, the condition continues to cause significant morbidity and mortality in the south-west Pacific and probably also in South-East Asia. There is a high prevalence in indigenous populations in the region and factors such as poverty, substandard housing, malnutrition, barriers to medical care and inadequate education are all likely to have a major impact on prevalence and outcome of bronchiectasis. Although bronchiectasis has been viewed as a disease of medium and large airways, there is now increasing evidence of the importance of small airways disease in bronchiectasis and that it may play an integral role in pathogenesis. Chronic inflammation of the bronchial wall by mononuclear cells is common to all types of bronchiectasis. A vicious cycle of bacteria (mediated lung toxicity and bacteria) provoked, host-mediated inflammatory lung damage has been described. If progressive lung damage with its attendant morbidity and mortality is to be prevented, this vicious cycle needs to be broken. The two distinct therapeutic goals in bronchiectasis are to reduce morbidity and to prevent progression of underlying disease. It may be possible to modulate the host response directly and thus reduce tissue damage, but the precise role of immuno-modulatory therapy in bronchiectasis is still unclear. The management of this hitherto neglected disease, which reaches almost epidemic proportions in some ethnic groups and is an ongoing source of considerable morbidity and mortality, requires a comprehensive, multidisciplinary approach, which can be modelled on the successful management of chronic asthma in New Zealand.

Immunological/physiological relationships in asthma: potential regulation by lung macrophages

There is now a consensus that T-cell-mediated inflammation and eosinophil activation in the bronchial wall contribute to the pathogenesis of asthma. However, the relationship between these immunopathological mechanisms and the observed physiological aberrations remain unclear. Here, Len Poulter and colleagues identify the links between T-cell-mediated inflammation and bronchial hyperresponsiveness, and propose a hypothesis for asthma pathogenesis in which the combination of immunological and physiological abnormalities may result in the promotion of disease. Furthermore, they suggest that an integral factor in the prevention of this process is the regulation of bronchial T-cell reactivity by a population of immunosuppressive macrophages.

Bronchial responsiveness and acute bronchodilator response in chronic obstructive pulmonary disease and diffuse panbronchiolitis

BACKGROUND

Diffuse panbronchiolitis (DPB) is characterised clinically by chronic airflow limitation and respiratory tract infection, and pathologically by chronic bronchiolar inflammation. To elucidate the functional differences between chronic obstructive pulmonary disease (COPD) and DPB the bronchial responsiveness to methacholine was compared in 64 patients with COPD and 32 patients with DPB, and the bronchodilator response was compared in 72 patients with COPD and 49 with DPB.

METHODS

Bronchial responsiveness to methacholine was determined by the dosimeter method and expressed as PD20FEV1, and bronchodilator response was measured as the change in percentage predicted response with 5 mg nebulised salbutamol.

RESULTS

Baseline FEV1 was similar in the two groups of patients. Patients with COPD were more responsive to methacholine than were those with DPB (geometric mean PD20FEV1 8.87 v 48.0 cumulative units). Reversibility of air flow obstruction, expressed as the difference between the percentage predicted postbronchodilator FEV1 and prebronchodilator FEV1, was significantly larger in patients with COPD than in those with DPB (7.87 (6.52)% v 4.16 (4.43)%).

CONCLUSIONS

The observation that patients with DPB differ substantially in bronchial responsiveness from those with COPD is thought to reflect the difference in the mechanisms of these two diseases--that is, airway disease in DPB and more parenchymal disease in the group of patients with COPD. The nature of bronchiolar inflammation in COPD and DPB is also different, possibly explaining the difference in bronchial responsiveness. More fixed airflow limitation as a result of structural bronchiolar lesions in DPB will explain the smaller reversibility of airflow obstruction.

Airway inflammation, bronchial reactivity and asthma

Asthma is a common disease of children the basis of which is a state of chronic immunological inflammation which causes bronchial hyperreactivity and renders the patient liable to develop widespread airways obstruction in response to a variety of stimuli. In many instances it is likely that the immunological inflammation results from ongoing antigenic stimuli with the release of chemical mediators responsible for short term bronchospasm and cytokines responsible for the ongoing inflammatory process. Other insults can apparently result in very similar immunological events in asthmatics, particularly viral infections and a similar process can be initiated in children without asthma, including those with chronic bacterial infections of the lungs. There are differences in the bronchial hyperreactivity of asthma and other diseases which suggest that in the asthmatic the mast cell is either different structurally or functionally and this renders the patient susceptible to exercise induced asthma in addition to the bronchial hyperreactivity to chemical mediators common to a number of diseases with hyperreactivity. There is good evidence of direct genetic control of atopy and the large majority of children with asthma are atopic but there is no direct genetic link between atopy and asthma and twin studies strongly suggest the existence of a 'permissive' asthma gene which will allow the disease to develop if there is an appropriate external trigger. The only drugs which have been shown to significantly reduce bronchial reactivity are the corticosteroids with a lesser effect noted for sodium cromoglycate and nedocromil. Inhaled corticosteroids can reverse the immunologic inflammatory process and reduce bronchial reactivity, sometimes to normal levels, but on stopping treatment the patient reverts back to the asthmatic state. At the present time it appears that controlled longterm inhaled corticosteroid therapy is the most rational treatment for significant perennial childhood asthma.

Complicating features of asthma

The recognition of factors other than asthma that make asthma worse, are confused with asthma, or occur concurrently with asthma and may or may not interact with asthma is as important as dealing with the asthma itself. In this article I have tried to give an overview of some of these factors: what they are, how they affect patients with asthma, and what to do about them. The recognition of a covert chronic sinusitis, for example, is often key to controlling a person's disease when it appears that everything is being done appropriately. Close attention to these factors will increase the success of treatment of asthma and improve the quality of life of patients.

Analysis of factors associated with bronchial hyperreactivity to methacholine in bronchiectasis

Nonspecific bronchial hyperreactivity (BHR) has been reported to occur in patients with bronchiectasis. To evaluate this further, we studied 77 patients with stable bronchiectasis (noncystic fibrosis) with special reference to the prevalence of BHR to methacholine (MCh), and its relation to lung function, sputum characteristics, concommitant asthma, and atopy. The concentration of MCh required to produce a fall of 20% in forced expiratory volume in 1 s (FEV1), PC20, was determined by Wright's nebulization tidal breathing method. BHR defined by a PC20 greater than or equal to 8 mg/ml was found in 21 of 47 (45%) subjects who underwent bronchial challenge. Presence of BHR was positively associated with low baseline spirometric values, diagnosis of asthma, long duration of disease, and elevated total IgE on univariant analysis, and was significantly related to FEV1/forced vital capacity (FVC) ratio and asthma on multiple regression analysis. Ten of the 21 hyperreactive subjects did not have clinical asthma, whereas all 11 of 22 subjects with clinical asthma who underwent bronchial challenge were hyperreactive. Among those with BHR, there was a positive correlation between PC20 and baseline FEV1. When patients were further classified into asthmatic and nonasthmatic subjects, a positive correlation between PC20 and FEV1 was seen only in those without asthma. Frequency of infective episodes and inflammatory score of sputum assessed by average daily volume, purulence, and leukocyte count did not differ significantly in the groups with and without BHR. These results suggest that BHR in patients with bronchiectasis is associated with coexistent asthma and worse spriometric values, and not with the severity of bronchial sepsis.