Background The earliest changes associated with airflow obstruction in asthmatic children are a proportionally greater reduction in FEF50% than in FEV1 using spirometry, and an increase in specific airway resistance (sRaw) using body plethysmography. Consequently, we hypothesized that sRaw could be better linked to FEF50% than to FEV1. The first aim was to assess the relationships between forced expiratory flows and sRaw in a large group of asthmatic children in a transversal study. We then performed a longitudinal study in order to determine whether sRaw of preschool children could predict subsequent impairment of forced expiratory flows at school age. Methodology Pulmonary function tests (sRaw and forced expiratory flows) of 2193 asthmatic children were selected for a transversal analysis, while 365 children were retrospectively selected for longitudinal assessment from preschool to school age. Principal Findings The transversal data showed that sRaw is differently related to FEF50% (−1/sRaw) and to FEV1 (near linearly). These results were further explained by a simple one-compartment lung model, which justified the shape of the observed relationships. As hypothesized, sRaw correlated more strongly to FEF50% than to FEV1 (r = −0.64 versus −0.39, respectively; p<0.001). In the longitudinal part of the study, sRaw at preschool age correlated with subsequent FEF50% (% predicted) (−0.31, 95% CI, −0.40 to −0.22), but weakly with subsequent FEV1 (% predicted) (−0.09, 95% CI, −0.20 to 0). Conclusion Specific Raw is more strongly related to FEF50% than to FEV1 and could be used in preschool children to predict subsequent mild airflow limitation.
A total of 106 children suffering from perennial rhinitis and/or asthma, and all allergic to Dermatophagoides pteronyssinus (DP), underwent nasal provocation challenge (NPC) with DP to determine the best method of diagnosis. Posterior rhinomanometry was uninterpretable in 17 patients and gave negative results in 31. Clinical scores for sneezing and rhinorrhea were more effective but did not diagnose the disorder in 11 children. However, nine of the 11 had significant increases in eosinophil count in the late phase. Clinical scores and cytology were also useful for assessing whether NPC with allergens was positive in children. The feasibility and safety of NPC with DP are high for rhinitic and stable asthmatic patients, but mild reactions may occur during the late phase.
We assessed the ability of innovative lung function tests to detect bronchial obstruction induced by methacholine bronchial challenge. Fifty-five recurrently wheezy infants (mean age 16 +/- 5.2 months) free of respiratory symptoms underwent baseline lung function tests. Forty-two completed the methacholine challenge. Maximal flow at functional residual capacity (VmaxFRC) was obtained using the squeeze technique; compliance and resistance of the respiratory system (Crs, Rrs) was measured with the passive expiatory flow volume technique; tidal volume breathing patterns were analyzed from recordings of respiratory rate (RR), tidal volume (VT), and inspiratory time divided by total cycle of duration (Ti/Ttot). Expiratory tidal flow volume (V/VT) curves were described with multiple indices such as the ratio of expiratory time necessary to reach peak tidal expiratory flow (Fpet) to expiratory time (Tme/Te). Transcutaneous oxygen tension (PtCO2) was measured as an indicator of response to methacholine challenge. Of 42 infants 41 responded to methacholine by a change > or = 2 standard deviations from baseline values. The mean SD unit changes were 9.8 in PtCO2, 3.7 for VmaxFRC, 2.8 for Crs, 2.09 for Rrs, 3.1 for RR, 1.6 for Ti/Ttot, 2.2 for Tme/Te 3.9 for PFVt. We conclude that these noninvasive lung function tests, especially VmaxFRC and Fpet, can be used to detect minor or moderate airway obstruction. Further studies are needed to determine the value of the tests in assessing bronchial disease and effects of its treatment.
Wheezing during infancy has been linked to early loss of pulmonary function. We prospectively investigated the relation between bronchial hyperresponsiveness (BHR) and progressive impairment of pulmonary function in a cohort of asthmatic infants followed until age 9 years. We studied 129 infants who had had at least three episodes of wheezing. Physical examinations, baseline lung function tests and methacholine challenge tests were scheduled at ages 16 months and 5, 7 and 9 years. Eighty-three children completed follow-up. Twenty-four (29%) infants had wheezing that persisted at 9 years of age. Clinical outcome at age 9 years was significantly predicted by symptoms at 5 years of age and by parental atopy. Specific airway resistance (sRaw) was altered in persistent wheezers as early as 5 years of age, and did not change thereafter. Ninety-five per cent of the children still responded to methacholine at the end of follow-up. The degree of BHR at 9 years was significantly related to current clinical status, baseline lung function, and parental atopy. BHR at 16 months and 5 years of age did not predict persistent wheezing between 5 and 9 years of age, or the final degree of BHR, but it did predict altered lung function. Wheezing that persists from infancy to 9 years of age is associated with BHR and to impaired lung function. BHR itself is predictive of impaired lung function in children, strongly pointing to early airway remodeling in infantile asthma.
Recurrent illness involving wheezing during the first years of life is transient in most children. The role of bronchial hyperresponsiveness as a factor influencing the persistence of wheezing from infancy to school age remains unknown. In a prospective study we investigated whether infants who wheezed and subsequently developed persistent asthma differed from infants who wheezed and later became asymptomatic either in the initial degree of bronchial hyperresponsiveness or in the persistence of bronchial hyperresponsiveness with age. One hundred and twenty-nine infants with three or more wheezing episodes before 2 yr of age were followed during 4 yr with a clinical evaluation and a methacholine challenge performed every 6 mo until the child was 4 yr old and once per year thereafter. The clinical score significantly improved with time in most children. The proportion of children with persistent wheezing after 2 and 4 yr of follow-up was only 31% and 20%, respectively. Persistent wheezers had significantly lower VmaxFRC values at initial evaluation and higher SRaw values at the end of follow-up than infants who became asymptomatic. We used transcutaneous oxygen tension (PtcO(2)) to measure the response to methacholine. No significant difference in PD(15) PtcO(2) between groups with subsequently different clinical progression was observed at initial evaluation. Bronchial hyperresponsiveness persisted 4 yr later in all children but children with persistent wheezing showed significantly lower PD(15) PtcO(2) values than children who became asymptomatic, as early as 30 mo of age. However, an acceptable early PD(15) PtcO(2) cut-off point predictive for subsequent clinical progression could not be identified. The level of bronchial hyperresponsiveness in infants who wheezed was not predictive of the persistence of asthma 4 yr later.
Allergic rhinitis is a common disease in childhood, but nasal cytology is rarely used by pediatricians. We compared two techniques of cell sampling, brushing and blowing the nose, among 77 children suffering from chronic rhinitis, of whom 59 were allergic. Staining by the May‐Griinwald‐Giemsa method enabled the evaluation of the density of cells and especially differential counting of the inflammatory cells. Staining by the Luna method was used as a control for the eosinophils. For the eosinophil count, we found a strong correlation between the two methods of collecting the nasal secretions ( r = 0.96). Because blowing the nose is painless and easy to perform, it is more appropriate than brushing in routine use for the diagnosis of allergic rhinitis in children and in nasal challenge with allergens.
Objective: To assess the difference in exhaled nitric oxide levels in atopic and nonatopic asthmatic patients treated with antiinflammatory drugs, and to compare exhaled nitric oxide measurement with lung function tests. Methods: Cross-sectional study with 45 consecutively selected patients with moderate and severe persistent asthma, aged between 6 and 17 years, and treated with anti-inflammatory drugs for at least 1 year. The patients were split into two groups: atopic ones (with positive skin tests) and nonatopic ones. The clinical and functional assessments and the measurement of exhaled nitric oxide were carried out concomitantly. Results: There was a male predominance (62.5%), with an age range between 6 and 13 years (mean of 10.4 years) in 85% of the patients. Neither the symptoms associated with asthma (p = 0.07), allergic rhinitis (p = 0.17), food allergy (p = 0.09), necessity of systemic corticosteroids (p = 0.10), antileukotrienes (p = 0.20) and antihistamines (p = 0.70), nor the three parameters used to assess lung function (FEV1, FEV1/FVC and FEF25-75%, p > 0.14) were statistically significant. The frequency of eczema (p < 0.005) and exhaled nitric oxide levels (p†<†0.001) were higher among atopic patients. Conclusion: Results suggest that clinical and functional stability of asthma among atopic patients does not necessarily reflect an efficient control over the inflammatory process and a higher probability for recurrence after discontinuation of anti-inflammatory therapy.
