Evaluation of bronchial challenge test results for use in assessment of paediatric eczema: a retrospective series.

BACKGROUND: Atopic dermatitis (AD), asthma, and allergic rhinitis are associated diseases involved in the atopic march. The bronchial challenge test (BCT) is a tool that evaluates airway hyperresponsiveness in patients with asthma. This study aimed to evaluate whether a positive BCT result is useful in assessment of paediatric AD. METHODS: This retrospective case series included 284 patients with AD who had BCT results. Clinical information and laboratory parameters were reviewed, including AD severity (using the SCORing Atopic Dermatitis [SCORAD]), skin hydration, and transepidermal water loss. RESULTS: Of the 284 patients who had BCT, 106 had positive BCT results and 178 had negative BCT results. A positive BCT result was associated with a history of asthma (P<0.0005), sibling with asthma (P=0.048), serum immunoglobulin E (P=0.045), eosinophil count (P=0.017), and sensitisation to food allergens in the skin prick test (P=0.027). There was no association between a positive BCT result and personal allergic rhinitis, parental atopy, sibling allergic rhinitis or AD, skin prick response to dust mites, objective SCORAD score, skin hydration, transepidermal water loss, exposure to smoking, incense burning, cat or dog ownership, or AD treatment aspects (eg, food avoidance and traditional Chinese medicine). Logistic regression showed significant associations of a positive BCT result with a history of asthma (adjusted odds ratio=4.05; 95% confidence interval=1.92-8.55; P<0.0005) and sibling atopy (adjusted odds ratio=2.25; 95% confidence interval=1.03-4.92; P=0.042). CONCLUSIONS: In patients with paediatric AD, a positive BCT result was independently and positively associated with personal history of asthma and sibling history of atopy, but not with any other clinical parameters.

Intraepithelial mast cells in allergic and nonallergic asthma. Assessment using bronchial brushings.

Mast cell mediators are known to contribute to the pathogenesis of asthma. There is some disagreement concerning the numbers of mast cells in asthmatic mucosa. In this study a standardized bronchial brush technique was developed and used to assess intraepithelial mast cells and other inflammatory cells in allergic and nonallergic asthmatic and nonasthmatic subjects. A total of 10 nonasthmatic (5 allergic) and 13 asthmatic (8 allergic) subjects with stable controlled asthma treated with beta-agonist only were assessed by history, spirometry, allergy prick tests, and methacholine airway responsiveness. During fiberoptic bronchoscopy, bronchoalveolar lavage (BAL) was performed from the middle lobe and standardized bronchial brushings were taken from the lingula and left lower lobe bronchi. Quantitative cell counts were performed blind to the clinical characteristics of the subjects. The average total cell recovery from the brushings was 1.04 (SEM 0.09) x 10(6) ml, with a cell viability of 64% (5.3%). Reproducible total cell and mast cell counts were obtained from brushings taken from two lobar bronchi (ICC 0.86). Mast cells were significantly elevated in asthmatic compared with nonasthmatic subjects (1.5 +/- 0.34 versus 0.15 +/- 0.06%). Allergic asthmatic subjects had the greatest numbers of mast cells (1.86 +/- 0.48%); however, the numbers present in brushings from nonallergic asthmatic subjects were also increased (1.03 +/- 0.45%). The mast cells had the staining characteristics of mucosal mast cells, with formalin-blockable metachromatic staining and positive staining for tryptase. Both asthmatic groups also had elevated BAL eosinophils, and neutrophils were elevated in nonallergic asthmatic subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway responsiveness in young black and white women.

The prevalence and severity of asthma appears to be greater in blacks than in whites. To determine if racial differences in airway responsiveness may explain these findings, methacholine challenge tests from 62 black and 238 white women 20 to 35 yr of age were evaluated. Subjects served as controls for a case-control study of the relation of airway responsiveness and preterm labor. Standardized questionnaires were used to obtain information on age, obstetrical history, education, income, cigarette smoking, medication use, and respiratory illnesses and symptoms. Total serum IgE was measured using a radioimmunoassay. Methacholine challenge testing was performed on all subjects 6 wk after delivery, and the provocative dose causing a 20% decrease in FEV1 (PD20) was calculated. Black women in the study had more pregnancies and children, were younger, less well educated and more impoverished, and reported greater cigarette smoking and less medication use than did the white women. Additionally, black women had higher geometric mean serum IgE levels (blacks: 65.4 IU versus whites: 20.0 IU; p < 0.001), lower FEV1 (blacks: 2.73 +/- 0.38 SD L versus whites: 3.19 +/- 0.39 L; p < 0.001), and greater unadjusted airway responsiveness than did white women (geometric mean PD20: blacks: 28.4 mumol versus whites: 38.8 mumol; p = 0.02). After adjusting for selective demographic and smoking differences, a significant additional effect of race on mean PD20 was found. However, after adjustment for level of serum IgE and level of FEV1, racial differences were no longer apparent.(ABSTRACT TRUNCATED AT 250 WORDS)

Occupational asthma: fate and management after the diagnosis.

The clinical and socio-professional fate of subjects with occupational asthma is not univocal. We re-examined twenty-nine subjects diagnosed in our center as suffering from this disease an average 14 months, SE 1.54 after the diagnosis. At the follow-up examination each patient underwent interview, spirometry and methacholine challenge, 18 patients (group A) had ceased exposure to the sensitizing agent but among them only 7 had been relocated in another area of the plant, the others had resigned or retired. The other patients had not changed workplace, 7 (group B) having had intermittent exposure to the offending agent and 4 (group C) having continued to be exposed daily. At the follow-up examination only 9 patients were asymptomatic, each of them belonging to group A, whereas in the other 9 of the same group symptoms persisted, although reduced. In group B and C all patients were still symptomatic and required pharmacologic treatment. Within group A patients who became asymptomatic had shorter duration of symptoms before diagnosis (12.9 months, SE 6.4 vs 23.9, SE 9.7), higher FEV-1 (96.1, SE 6.7 vs 86.9, SE 5.6) and PD20FEV-1 (1773.4 micrograms, SE 590 vs 730.8, SE 295) at the time of the diagnosis and showed a significant (p < 0.01) increase in FEV-1 (from 96.1, SE 6.2 to 101.6, SE 5.5) and a tendency to decrease in bronchial reactivity to methacholine at the follow-up examination. At the time of the follow-up examination only 5 out of 29 patients (17.2%) had been contacted by the compensation board.(ABSTRACT TRUNCATED AT 250 WORDS)

Acoustic vs. spirometric assessment of bronchial responsiveness to methacholine in children.

To study wheezing as an indicator of bronchial responsiveness during methacholine challenge (MC) in children, we used computer analysis of respiratory sounds and compared wheeze measurements to routine spirometry. MC was performed in 30 symptomatic subjects (sympt), age 11 +/- 3.1 years (mean +/- SD), with suspected asthma and in 12 controls (contr), age 10 +/- 3.4 years. Respiratory rate (RR), spirometry, arterial oxygen saturation (SaO2), and cough were registered until the concentration provoking a > or = 20% fall in forced expiratory flow in 1 second (FEV1;PC20), or the end point (8 mg/mL) was reached. For 1 min after each inhalation, sounds over the trachea and posterior right lower lobe were recorded together with calibrated airflow. Computer analysis of respiratory sounds was used for objective wheeze quantification. Wheezing was measured as its duration relative to inspiration (Tw/Ti) and expiration (Tw/Te). Seventeen of the sympt group developed wheezing (sympt/W) with > or = 5% Tw/Ti or > or = 5% Tw/Te. Thirteen of the sympt did not wheeze (sympt/no W). Three contr developed wheeze (contr/W) while 9 did not (contr/no W). In sympt/W, RR increased from 20 +/- 6.2 per min at baseline to 25 +/- 9.2 (P < 0.05) at the MC concentration provoking wheeze (PCw), and SaO2 decreased from 97.4 +/- 1.2% to 95.3 +/- 2.4 (P < 0.05). In contr/W, RR did not change, but SaO2 decreased from 97.3 +/- 1.5% to 95.7% +/- 1.2% (P < 0.05). Wheezing occurred at both recording sites and was as common during inspiration as during expiration.(ABSTRACT TRUNCATED AT 250 WORDS)

[The assessment of bronchial patency by conducting broncholytic and loading tests in patients with pulmonary pathology]. / Otsenka bronkhial'noi prokhodimosti pri provedenii bronkholiticheskikh i nagruzochnykh prob u bol'nykh s legochnoi patologiei.

Reproducibility of the parameters of bronchial patency was studied in 31 patients with nonspecific pulmonary diseases, changes in the parameters of bronchial patency during the berotek and loading tests--in 28 healthy subjects, the dynamics of bronchial patency in these tests and the value of separate methods of study of bronchial patency--in 119 patients with active pulmonary tuberculosis. The parameters of spirography, forced expiration flow-volume and general plethysmography were used. Assessment of the results of the pharmacological and loading tests require consideration of reproducibility of the parameters and their changes in healthy subjects in connection with a broncholytic action on the tone of bronchial muscles. The table of limited diagnostically insignificant functional changes in bronchial patency in given. When evaluating the results of functional tests, it is expedient to use a combination of the parameters of spirography, the curve of forced expiration flow-volume and general plethysmography and in the choice of method preference should be given to the registration of the curve of forced expiration flow-volume. The most sensitive parameters of the dynamics of bronchial patency in the broncholytic and loading tests have been developed.

Post-test probability of asthma following methacholine challenge.

Using recently published data, a nomogram was constructed to estimate the likelihood of asthma following methacholine challenge. Based on Bayes' theorem, the nomogram makes use of the sensitivity and specificity of methacholine challenge to calculate the post-test probability of asthma once the physician makes a determination of the pretest probability, that is, the likelihood of asthma before the test results are considered. A family of curves is presented to cover several levels of cumulative breath units at which the test could become positive, and a single curve is presented for a negative test after 224 cumulative breath units. Separate curves are presented for smokers and nonsmokers. The estimate of pretest probability is most crucial in negative tests where likelihood of asthma is considered high, and in positive tests in patients in whom asthma is considered unlikely. Although these curves will not apply precisely to a different data base, the concept of the relationship between pretest and post-test probability helps in the interpretation of the test results and stresses the importance of using all available information in making a diagnosis.