Bronchial Lability Research Articles

Clinics in Rheumatic Diseases

Exercise tests were carried out on 18 children who had had wheezy bronchitis under the age of 5 years during hospitalization 7 years previously. A control group of 12 children who had been hospitalized with gastroenteritis at the same time were also studied. It was found that there was still a significant increase in bronchial lability among the wheezy bronchitis group compared with the controls, and this was especially obvious in the 7 children who had continued to have mild episodes of wheezing. It is suggested that the same abnormal mechanism operates in at least some cases of wheezy bronchitis as it does in asthma.

Atopy does not predispose to RSV bronchiolitis or postbronchiolitic wheezing.

Twenty-six 8-year-old children who had had respiratory syncytial virus (RSV) bronchiolitis in infancy and their paired controls underwent skin and blood tests to assess the role of immunodeficiency and atopy in the pathogenesis of RSV bronchiolitis and the wheezing that may follow it. There was no difference between patients and controls in prevalence of atopy; positive results of prick tests to common antigens; eosinophil counts; yeast opsonisation defect; C2 deficiency; IgG, IgA, IgM, and IgE concentrations; or IgE antibody to dermatophagoides, timothy-grass pollen, and cat fur. Those of the children who had had RSV bronchiolitis and who continued to wheeze had a slightly higher mean eosinophil count and levels of IgE antibody to dermatophagoides than those who did not wheeze. Exercise-induced bronchial lability, though higher in patients than controls, did not correlate significantly with eosinophil counts or IgE concentrations. The genetic factors predisposing to RSV bronchiolitis and postbronchiolitic wheezing may differ from those predisposing to atopic asthma, though exclusive breast feeding may protect against both.

The Relationship Between Flow Transients and Bronchial Lability in Cystic Fibrosis

Patients with cystic fibrosis (CF), in contrast to asthmatic subjects, often show a larger increase than decrease (bronchial lability) in peak flows following exercise. Children with CF also often have large supramaximal expiratory flow transients, produced by rapid expulsion of air from conducting airways that are being dynamically compressed. We studied the relationship between bronchial lability and flow transients to explain the peculiar form of bronchial lability found in certain CF patients. At baseline, six of seven CF patients had flow transients, suggestive of decreased resting tone of the conducting airways. Following exercise, there was a strong positive correlation (r = 0.76, P less than .01) between changes in peak flow and changes in the volume of the flow transients. Four subjects increased both, two did not change either, and in one subject both peak flow and the volume of the flow transient decreased. This study suggests that the unique, previously unexplained form of postexercise bronchial lability observed in some CF patients is probably due mainly to flow transients that contribute to peak flows. These transients are probably related to increased compliance of the conducting airways in this disease.

Protective effects of repeated short sprints in exercise-induced asthma.

Many asthmatic patients demonstrate bronchial lability with a six-minute period of exercise, which is characterised by an initial bronchodilatation followed by bronchoconstriction. This early bronchodilatation response has been further analysed by investigation of the effects of repeated 30-second sprints before and after a six-minute run. It was found that these repeated short sprints did not induce bronchoconstriction, resulted in less bronchoconstriction after a subsequent six-minute run, and caused bronchodilatation if exercise-induced bronchoconstriction was present. It is postulated that this effect may be related to an increase in circulating catecholamines or altered vagal-sympathetic balance.

Comparison of normal and asthmatic circadian rhythms in peak expiratory flow rate.

A computer technique (cosinor analysis) has been used to evaluate circadian rhythms in airway calibre in normals and asthmatics. Two hundred and twenty-one normal subjects recorded peak expiratory flow rate (PEFR) at home four times a day for seven days. Rhythm detection was statistically significant in 145 of them (65.6%) who showed a mean amplitude of 8.3% of individual mean PEFR (+/- SD 5.2%). Amplitude was independent of age, sex, atopy, family history of asthma, and smoking habit. Fifteen of them were also studied three times a day for five days in the laboratory with flow-volume loops. Eleven showed significant PEFR rhythms at home. No single measurement from the flow-volume loop showed periodicity in as many of them but rhythms were now also detected in the other four normal subjects in some components of the loop. Fifty-six asthma patients were studied with a similar protocol of PEFR measurement and compared with the 145 rhythmic normal subjects. Mean phases of the normal and asthmatic rhythms were not significantly different with acrophases (peak of rhythm cycle) at 1557 and 1526 respectively. The mean asthmatic amplitude was, however, significantly greater at 50.9%. Nocturnal asthma, therefore, probably represents an exaggeration of a normal circadian rhythm in airway calibre. The amplitude of the PEFR rhythm is an index of bronchial lability and is thus valuable in monitoring asthma patients. An amplitude of greater than 20% should be a useful screening test for asthma.

Site of bronchospasm in exercise-induced asthma.

Bronchoconstriction induced by a bicycle ergometer reached a maximum at the 3rd and 6th minutes after exercise. The values of maximal expiratory flow measured at 25, 50 and 75% of forced vital capacity, peak expiratory flow and specific airways conductance, in cases of exercise-induced asthma, indicated that the obstruction of the large airways precedes and, in intensity, surpasses that of the small ones. Bronchial lability index was used for the comparison of the changes in the different parameters. Bronchoconstriction provoked by exercise is considered as a suitable model for the general study of the pathophysiology of bronchial asthma.

Alterations in Pulmonary Function Following Respiratory Viral Infection

Respiratory viral illness is a major cause of morbidity in both adults and children. This report focuses on both the acute and chronic effects on respiratory function of these ubiquitous infections. Infant airways are particularly vulnerable due to the relatively low conductance in immature peripheral airways. Bronchiolitis, caused predominantly by respiratory syncytial virus, is the most important of these viral illnesses and is emerging as a major risk factor for the subsequent development of obstructive airway disease in adults, possibly by interference with normal alveolar proliferation. The basic pathogenic mechanism involved in adult respiratory viral infection is bronchial hyperreactivity, presumably secondary to epithelial damage and resultant sensitization of rapidly adapting airway receptors. In addition, there may be virus-related alterations in the autonomic and humoral regulation of airway tone. Viral infections may alter the effects of common air pollutants on respiratory function.

Study of 8-year-old children with a history of respiratory syncytial virus bronchiolitis in infancy.

Thirty-five children known to have had respiratory syncytial virus bronchiolitis in infancy were examined at the age of 8 and their respiratory function tested. The results were compared with those in 35 controls matched for age, sex, and social class. Although 18 of the children who had had bronchiolitis in infancy had experienced subsequent episodes of wheezing, these were neither severe nor frequent in most cases and had apparently ceased by the age of 8. Nevertheless, the mean exercise bronchial lability of the children who had had bronchiolitis was significantly higher than that of the control children and the mean peak expiratory flow rate at rest significantly lower. Atopy, assessed by family and personal history alone, did not seem to be related to either bronchiolitis or wheezing episodes after bronchiolitis. The parents of the children who had had bronchiolitis smoked significantly more cigarettes during the infant's first year of life than those of the control children. The results suggest that bronchiolitis and childhood asthma are not closely related. Bronchial hyperreactivity might be inherited independently of atopy, but environmental factors seem the most likely link between severe respiratory infection in infancy and chronic or recurrent respiratory illness in adult life.

Clinical, physiological, and psychological study of asthmatic children attending a hospital clinic.

The results of an investigation into the relationship between clinical, physiological, and psychological factors in 63 children with asthma are reported. The children were classified according to the severity of their asthma by reference to their regular drug usage and also were assessed in terms of the quality of control of the asthma and the degree of compliance with medication. Lung function tests and exercise tests were also carried out. Standard questionnaires to detect emotional or behavioural `deviance9 in the children were completed by their mothers and by class teachers and assessments made of their personalities and the mental health of their mothers. Though the percentage of children with deviant scores on the questionnaire was high, it was not much greater than had been found among other (nonasthmatic) London children. Resting peak flow rate, measured as the mean of at least three tests on different clinical attendances, reflected the clinical grading of severity. Deviant children had lower levels of peak flow than non-deviant children, but their bronchial lability as measured by exercise-induced asthma was similar. Poor control of the asthma was associated with emotional or behavioural deviance, whereas deviance was independent of the severity of the asthma per se .

IgE, parasites and asthma in Tanzanian children

Two rural Tanzanian primary schools were surveyed to test the hypothesis that parasitic infestation prevents the development of asthma. 242 pupils were interviewed to determine the prevalence of pupils with recurrent episodes of wheezing. The nineteen pupils so discovered had more exercise-induced bronchial lability than equivalently exercised controls. More girls (12.8%) than boys (3.3%) had asthma. In one school, 77% of the controls had faecal parasites, mainly Ascaris spp., and in the other school 55% of the controls had Schistosoma haematobium in their urine. Parasites were found in similar proportions in the asthmatics. The mean serum IgE for the whole population was 3174 u/ml with no demonstrable difference between the asthmatics and controls. There was no difference in immediate cutaneous hypersensitivity to twenty-two allergens between the asthmatics and controls. These findings suggest that parasitic infestation does not prevent the development of asthma.

Bronchial lability in cystic fibrosis.

Abstract. We investigated the airway's response to exercise in cystic fibrosis (CF). Due to the reported high incidence of allergy in CF we tried to demonstrate the well documented post‐exercise bronchospasm of asthma in patients with CF. Subjects ran on a treadmill for 6 minutes at a speed of three miles per hour and a gradient of 15°.For the 12 controls studied, the mean % rise in peak expiratory flow rate (PEFR) during excercise was 4.7% and the mean % fall in PEFR during recovery was 0.7%. For the eight atopic asthmatics studied the mean % rise in PEFR was 12.2% and the mean % fall in PEFR was 33.7%. For the 29 patients with CF, the mean % rise in PEFR was 20.3% and the mean % fall in PEFR was 3.1%. Patients with CF showed no statistically significant post‐exercise constriction compared with the controls, while asthmatic patients showed a post‐exercise % fall in PEFR significantly greater than seen in controls (p<0.001) or in CF patients (p<0.001). No patient with CF showed post‐exercise bronchospasm, nor was there any difference between patients with CF who had positive skin tests to common allergens and those who did not in their pattern of bronchial lability. It is suggested that the general desensitization therapy should not be instituted in patients with CF merely on the basis of positive skin tests, without more stringent criteria such as characteristic seasonal variation in respiratory symptomatology, family history of atopy and positive bronchial inhalation provocation tests.

Exercise-Induced Bronchial Lability in Wheezy Children and Their Families

Studies have been carried out to investigate bronchial lability as assessed by means of standardized running exercise tests. It was found that children who had been wheezy as infants still had an abnormal degree of bronchial lability, even if they were asymptomatic, and closely resembled children who had continued to wheeze. The relatives of asthmatic children displayed a high incidence of bronchial lability. atopic diseases, and positive skin tests, and a similar incidence was found in the relatives of babies with wheezy bronchitis. The difference from a control population was particularly noticeable in the healthy relatives of wheezy children. Studies in monozygotic and dizygotic twins have shown a very high incidence of concordance for asthma, particularly when bronchial lability is taken into account. These studies suggest a common genetic basis for wheezing in childhood, based on the inheritance of bronchial lability. The difference in response of the actively asthmatic subject from that of other labile subjects suggests that additional environmental factors are necessary to interact with the inherited bronchial lability.

Letter: Bronchial lability in cystic fibrosis.

Letter: Bronchial lability in cystic fibrosis.

The place of cromolyn sodium in the long-term management of childhood asthma based on a 3- to 5-year follow-up

The long-term value of cromolyn sodium in the management of childhood asthma has been assessed over 3 to 5 years in 46 children with chronic perennial asthma who were not initially receiving corticosteroid therapy. The need to use steroids because of poor control during treatment with SCG was taken as a criterion of SCG treatment failure. Most such failures occurred early, but there were a few late treatment failures so that the proportion of SCG successes leveled of at 65% by the fourth and fifth years. Failure with SCG tended to occur in the younger children whose disease had progressed rapidly. By the fifth year, half of the children successfully treated by SCG had been able to discontinue use of the drug, and these children, but not the others, had diminished bronchial lability as shown on exercise testing.

Exercise-induced bronchial lability in monozygotic (identical) and dizygotic (nonidentical) twins

Exercise tests and skin tests were carried out on 8 pairs of identical and 7 pairs of nonidentical twins. The pairs of twins were selected so that at least one member of each pair had clinical asthma or was a first-degree relative of a patient with asthma and had an increased bronchial lability on exercise. Clinical concordance for active asthma was found in 3 of the identical pairs but only one of the nonidentical pairs. In 2 further identical pairs, one subject had active asthma and the other had a past history of asthma. In 6 of the identical pairs, the other twin was also found to have an increased bronchial lability, while only one of the nonidentical pairs was concordant in this respect. From the point of view of atopy shown by skin tests, 6 identical pairs were concordant compared with one of the nonidentical pairs. Concordance for atopy and bronchial lability did not necessarily go together. The significantly higher rate of concordance among the identical twins, for both increased bronchial lability and atopy, shows the importance of inheritance for these characters.

Contribution of airway collapse to supramaximal expiratory flows.

Contribution of airway collapse to supramaximal expiratory flows.

Proceedings: Genetics of wheezy children assessed by exercise-induced bronchial lability.

Proceedings: Genetics of wheezy children assessed by exercise-induced bronchial lability.

Exercise-induced bronchial lability and atopic status of families of infants with wheezy bronchitis.

Exercise-induced bronchial lability and atopic status of families of infants with wheezy bronchitis.

Prevalence of exercise-induced bronchial lability in families of children with asthma.

Prevalence of exercise-induced bronchial lability in families of children with asthma.

Bronchial lability in cystic fibrosis.

A total of 18 403 men aged between 40 and 64 years took part in a screening examination which included a self-administered version of the London School of Hygiene questionnaire on chest pain and intermittent claudication. The yield of positives for "angina" and "history of possible infarction" was about twice as high as with interviewers, but the positive groups obtained by the two techniques differed little in their association with electrocardiographic findings or in their ability to predict five-year coronary mortality risk. This risk ranged from 0-9% in men negative to questionnaire and electrocardiograms (ECG), to 4-3% for those with positive ECG but no symptoms, 4-5% for those with angina and negative ECG, up to 16% for those with angina and positive ECG. The self-administered version of this questionnaire provides a simple and convenient means of identifying individuals with a high risk of major coronary heart disease.