Hélène Turcotte

Comparative degree and type of sensitization to common indoor and outdoor allergens in subjects with allergic rhinitis and/or asthma.

Background and objectives The determinants of variability in the clinical expression of atopy are still to be documented. The goals of this study were to determine, in subjects with a clinical diagnosis of symptomatic asthma or rhinitis, what is the possible contribution of different types of indoor and outdoor allergens to the development of their disease, by looking at the prevalence and degree of sensitization to these allergens according to age and gender.

Near-fatal asthma : clinical and physiologic features, perception of bronchoconstriction, and psychologic profile

We studied 19 subjects with asthma (11 men and eight women, aged 20 to 66 years), 6 months to 5 years after a near-fatal (NF) episode of asthma (NF group). Mean duration of asthma was 16.3 +/- 2.4 years. On reevaluation, all subjects were using an inhaled beta 2-agonist and inhaled steroids (mean daily dose of budesonide, 1070 micrograms [N = 5], and beclomethasone, 1079 micrograms [N = 14]). Two subjects were taking prednisone, 10 and 15 mg/day. Subjects were matched for age, sex, atopic status, baseline FEV1, and medication use to a control group (C group) of subjects with asthma who had never experienced an NF asthma episode. All subjects had the following evaluation: (1) questionnaire on the characteristics of their asthma, (2) spirometry, (3) morning and evening measurements of peak expiratory flow rates (PEFR) with daily recordings of asthma symptoms for 4 weeks, and (4) psychometric evaluation with the Minnesota Multiphasic Personality Inventory. Ten subjects of the NF group and 13 of the C group had a methacholine challenge with scoring of dyspnea on a modified Borg scale. Mean percent predicted (+/- SEM), FEV1, FVC, and PEFR were similar for the NF and C groups with respective values of 63.4 (4.4), 61.3 (5.6), 81.1 (4.5), 79.1 (3.8), 61.3 (5.6), and 62.4 (6.1). Geometric mean of the provocative concentration of methacholine causing a 20% drop in FEV1 (milligrams per milliliter) was 0.61 for the NF group (N = 10) and 1.18 for the C group (N = 13).(ABSTRACT TRUNCATED AT 250 WORDS)

Asthma and sleep apnea in patients with morbid obesity: outcome after bariatric surgery.

Background: Asthma and sleep apnea syndrome (SAS) are frequently reported in obese patients. The authors determined the prevalence of asthma and SAS in morbidly obese patients and the effect of biliopancreatic diversion with duodenal switch (BPD-DS) on these conditions. Methods: 398 patients were evaluated for bariatric surgery in a university-affiliated tertiary care center. All patients completed a written questionnaire on asthma and SAS before BPD-DS. In addition, 139 patients also completed a questionnaire on their general health status, including asthma and SAS, 2 years after the procedure. Results: For the cohort of 398 patients, the prevalence of self-reported asthma was 30.4% and that of SAS, 32.2%. No significant association was found between asthma and SAS diagnosis (P =0.10). Significant relationships were observed between the diagnosis of asthma and age, hip circumference, waist/hip ratio, weight and BMI of the patients as well as between a diagnosis of SAS and gender, waist circumference, hip circumference, waist/hip ratio, weight and BMI. 2 years after surgery (mean BMI was reduced from 51.4 to 30.5 kg/m2), asthma was reported improved in 79.3% of patients and SAS was improved in all but one with this condition; among 29 SAS patients using CPAP before surgery, only 4 were still using this treatment after 2 years. Conclusion: The prevalence of asthma and SAS is high in the morbidly obese population and is associated with markers of obesity. We found no association between the diagnosis of asthma and SAS diagnosis in this population. BPD-DS improved self-reported severity of asthma and SAS symptoms.

Influence of natural antigenic exposure on expiratory flows, methacholine responsiveness, and airway inflammation in mild allergic asthma

BACKGROUND This study looked at respiratory symptoms, peak expiratory flow rates (PEFRs), airway responsiveness to methacholine and inflammatory changes on bronchial biopsies, bronchial lavage (BL), and bronchoalveolar lavage (BAL) during natural antigenic exposure in nine subjects with pollen-sensitized seasonal asthma. METHODS The subjects recorded daily symptoms of asthma, cough and rhinitis, and morning and evening PEFRs between January and September, during and out of the pollen exposure. Baseline forced expiratory volume in 1 second, forced vital capacity, and methacholine responsiveness were measured every 3 to 4 weeks. BAL, BL, and bronchial biopsies were performed in the pollen season at the initial increase of asthma symptoms and out of pollen exposure. RESULTS At the time of bronchoscopy during the pollen season compared with out of season, asthmatic subjects had an increase in asthma symptom score (1.18 +/- 0.24/0.44 +/- 0.18, p < 0.05), a reduction of PEFR (407 +/- 23/442 +/- 20 L/min, p = 0.02), and a decrease in PC20 (1.15/1.48 mg/ml, p = 0.05). In asthmatic subjects, median BAL and BL cell counts and cell differentials during or out of antigenic exposure were similar, but BAL and BL eosinophils and metachromatic cells counts were always higher than in healthy subjects. In comparison with controls, biopsies obtained in asthmatic subjects showed airway lesions such as epithelial desquamation, squamous cell metaplasia, thickening of basal membrane, inflammatory cells (p < 0.05 for neutrophils), edema, and ciliary abnormalities. During pollen exposure, inflammatory signs increased, but this change was only significant for the extent of epithelial desquamation and neutrophil counts. No significant correlation was found between the intensity of airway inflammation and changes in airway responsiveness. CONCLUSIONS In subjects with mild allergic asthma and pollen-induced asthma, seasonal antigenic exposure was associated with an increase in epithelial shedding and in the number of neutrophils on bronchial biopsies, suggesting a mild increase in baseline airway inflammation. However, these changes were not correlated with increases in airway responsiveness.

Characteristics of Bronchial Asthma with Incomplete Reversibility of Airflow Obstruction

BACKGROUND Incomplete reversibility of airflow obstruction (IRAO) can be observed in some asthmatic patients without significant smoking history nor evidence of other respiratory condition. The characteristics of this group remain however to be defined. METHODS We compared 18 asthmatic patients with persistent airflow obstruction, defined as an FEV1 < or = 75% predicted despite optimal corticosteroid treatment, to others with complete reversibility of airflow obstruction, paired for age and gender (CRAO, FEV1 > 80% of predicted). RESULTS Mean duration of asthma was 31.6 years for IRAO patients and 17.7 for the CRAO group and mean baseline FEV1 was 48.6 +/- 2.6% and 89.3 +/- 3.4%, respectively. Patients with IRAO had more severe airflow obstruction and hyperinflation than those with CRAO, while lung compliance and CO diffusion were similar. Overall healthcare use was similar in the two groups, but those with IRAO had a greater global asthma-related discomfort, increased diurnal variation of airflow obstruction and used higher doses of inhaled corticosteroids than those with CRAO. Patients with IRAO had slightly increased airway wall thickness on high resolution chest tomography compared with CRAO. Baseline FEV1 however, was not correlated with the measured airway wall thickness. CONCLUSION We found that asthmatic patients with IRAO have a more severe asthma and asthma of longer duration than asthmatic subjects with CRAO. Our data suggest that in asthma, IRAO may result from long-standing airway inflammation and associated structural changes, although this remains to be further documented.

Comparative efficacy of salbutamol, ipratropium, and cromoglycate in the prevention of bronchospasm induced by exercise and hyperosmolar challenges

We compared the inhibitory effects of inhaled salbutamol (S), ipratropium (I), and cromoglycate (C) on bronchospasm induced by exercise (EX) or hyperosmolar (HY) saline aerosol in a group of 11 subjects with stable asthma. Each subject had eight tests in a randomized order, four EX and four HY challenges, each preceded by the double-blind inhalation of either a placebo, 200 micrograms of S, 80 micrograms of I, or 4 mg of C. This study demonstrated that the three drugs protected against the two types of challenges in almost all subjects. Although we observed a large interindividual variability in the airway response to the challenges, there was no statistically significant difference in the mean percent protection after HY or EX challenges when these challenges were preceded by S, I, or C (p greater than 0.05). Moreover, for EX- and HY-induced bronchospasm, the mean percent protection afforded by the three medications was in the same order (S greater than I greater than C), although the protective effect against EX-induced was weaker than against HY-induced bronchospasm. This suggests that hyperosmolarity, although it may not be the sole factor involved, plays a role in EX-induced bronchospasm.

Clinical, Physiological and Radiological Features in Asthma with Incomplete Reversibility of Airflow Obstruction Compared with Those of COPD

OBJECTIVES To compare clinical features, pulmonary function and high-resolution computed chest tomography (HRCT) findings of asthmatic patients with a component of incomplete reversibility of airflow obstruction (AIRAO) with those of patients with smoking-induced chronic obstructive pulmonary disease (COPD). METHODS Thirteen patients with COPD (six males and seven females, mean age 59 years, mean smoking 50.5 pack-years) and 14 patients with AIRAO (six males and eight females, mean age 52 years) despite optimal treatment, with no significant smoking history (mean 1.5 pack-years) and no significant environmental exposure or any other respiratory disease, were studied. Patients had respiratory questionnaires, pulmonary function tests, allergy skin-prick tests and an HRCT to evaluate possible parenchymal or bronchial abnormalities. Eight patients in each group also had exercise tests. All patients were stable at the time of the study. RESULTS As expected, atopy was more prevalent in AIRAO (n=13) than in COPD (n=1) patients. Mean forced expiratory volume in 1 s (FEV1) and forced vital capacity (percentage of predicted value) were 39% and 61%, respectively, in COPD patients and 49% and 71%, respectively, in AIRAO patients; FEV1 improved by 18% in COPD patients and and by 22% in AIRAO patients after use of inhaled salbutamol. Mean functional residual capacity was greater in COPD patients than in AIRAO patients (178% versus 144% of the predicted value), while the mean carbon monoxide diffusing capacity of the lungs (DLCO) was lower in COPD patients than in AIRAO patients (62% versus 89% of the predicted value). Exercise tolerance was similar in both groups, as were postexercise changes in arterial oxygen pressure (PaO2). Emphysematous changes were observed in COPD patients and AIRAO patients who had evaluable HRCTs (10 versus two patients, although very mild in asthma), bronchial dilations (zero versus six patients), bronchial wall thickening (two versus eight patients) and an acinar pattern (one versus five patients). Mean thickness of the large airway wall to outer diameter (intermediary bronchus) ratio was 0.176 in COPD and 0.183 in AIRAO (P>0.05). CONCLUSIONS Asthma may lead to physiological features similar to COPD but may be distinguished by demonstrating a preserved DLCO and a higher ratio of airway to parenchymal abnormalities on HRCT scan.

Prevalence of respiratory symptoms in an athlete population

This study aimed to look at the prevalence and type of respiratory symptoms experienced by athletes and to assess the possible influence on the perception of symptoms of training duration and environment. A group of 698 athletes (107 with diagnosed or self-reported asthma) filled out a questionnaire on their respiratory condition. They exercised either in cold air (n = 176), dry air (n = 384), humid air (n = 95) or mixed dry and humid air (n = 43). Past exercise-related symptoms reported by athletes were breathlessness (48.7%), phlegm production (22.8%), wheezing (15.6%), cough (15.2%), and chest tightness (7.4%). Only 25% of asthmatic athletes reported having current exercise-induced symptoms of breathlessness, 21.7%, wheezing and 17.4%, chest tightness; current exercise-induced symptoms of breathlessness, wheezing or chest tightness were also reported, respectively, in 38.9%, 3.6% and 2.7% of athletes without a diagnosis of asthma. The perception of exercise-induced symptoms was not influenced by the duration of training or environment. In conclusion, (1) a minority of asthmatic athletes report troublesome respiratory symptoms with exercise, (2) breathlessness is not more frequently reported in asthmatic athletes than in those without such diagnosis while cough and wheezing are more common in asthmatic subjects and (3) the prevalence of respiratory symptoms is independent of training environment and duration of training.

Deep Inspiration Avoidance and Airway Response to Methacholine: Influence of Body Mass Index

OBJECTIVE To evaluate the effects of deep inspiration avoidance response to methacholine inhalation in 23 nonobese (body mass index between 18 kg/m2 and 30 kg/m2) and 27 obese (body mass index 30 kg/m2 or greater), nonatopic, nonasthmatic normal subjects. METHODS Each subject had four methacholine challenges. In tests A and B, the first postmethacholine forced expiratory volume in 1 s (FEV1) was measured at 30 s and 3 min postinhalation, respectively; tests C and D were single-dose tests (using the final dose of test B), with the first postmethacholine FEV1 being obtained at 3 min, without (test C) or with (test D) 20 min of deep inspiration avoidance before inhalation. RESULTS The mean provocative concentrations inducing a 20% fall in FEV1 on tests A and B were 80.6 mg/mL and 28.5 mg/mL (P<0.0001) in nonobese subjects, respectively, and 56.3 mg/mL and 21.5 mg/mL (P<0.0001) in obese subjects, respectively. No significant differences were observed in test A or B between control and obese subjects. Mean falls in FEV1 for tests C and D were 20.3% and 40.0% (P=0.0003) in nonobese subjects, respectively, and 18.5% and 23.6% (P>0.05) in obese subjects, respectively. CONCLUSIONS As previously observed in patients with asthma, the present study found that nonasthmatic obese subjects had no increase in the fall in FEV1 after deep inspiration avoidance before methacholine, whereas nonobese subjects did, suggesting that obesity alters airway function. No significant changes were found between groups for symptom perception.

Prevalence and characteristics of late asthmatic responses to exercise

The prevalence and characteristics of late asthmatic responses to exercise were studied in an adult asthmatic population. Twenty-four subjects (eight male and 16 female), aged 17 to 39 years (mean, 23.7 years), performed a 6-minute exercise on a bicycle ergometer at 75% of their maximum oxygen intake. FEV1 was measured at regular time intervals up to 8 hours after exercise. Seven subjects demonstrated a late asthmatic reaction defined as a fall in FEV1 greater than 10% between 2 to 8 hours. Bronchial reactivity to histamine was unchanged 24 hours after the exercise, compared to baseline. On a control day, a fall in FEV1 similar to the one observed after exercise was induced by methacholine inhalation. Measurements of FEV1 were done at the same time intervals as on exercise day. Neutrophil chemotactic activity was measured in the serum of 15 subjects, on exercise day for early responders, and on the 3 test days for subjects with a dual response. There was no difference between subjects with an isolated early or late response for age, sex, or atopic status. Baseline expiratory flows and nonspecific bronchial reactivity to histamine were similar in both groups. These results demonstrate the occurrence of a late asthmatic response in 30.4% of the population studied. There was no significant change of nonspecific bronchial responsiveness after the late asthmatic response to exercise. No significant increase in neutrophil chemotactic activity could be observed.