[Pulmonary function testing in children]. / Les explorations fonctionnelles respiratoires chez l'enfant.

Pulmonary function testing in child can be realized in different circumstances: to confirm a diagnosis (asthma), to monitor evolution of a chronic pulmonary disease (asthma, bronchodysplasia, mucovicidosis...) or to quantify a possible pulmonary dysfunction in various pathologies (immune defect, dermatomyositis, scoliosis, drepanocytosis...).

[Allergic rhinitis in childhood]. / La rhinite allergique de l'enfant.

Prevalence of allergic rhinitis has increased in the past years. The determination of the aeroallergens involved is important. Children with persistent rhinitis must be evaluated for asthma. Early treatment of allergic rhinitis may avoid asthma onset. The management of allergic rhinitis must include allergen avoidance, pharmacological treatment and immunotherapy. Sublingual swallow immunotherapy is a safe and effective method of treatment.

Safety of various dosage regimens during induction of sublingual immunotherapy. A preliminary study.

BACKGROUND: Sublingual immunotherapy (SLIT) has been demonstrated to be a viable alternative to injection immunotherapy. Administration of high doses of allergens to ensure efficacy has been shown to be well tolerated. The aim of the present study was the first step to address the issue of fast-induction regimens using various induction SLIT regimens in paediatric and adult patients. METHODS: Sixty-four patients (age range 5-46 years) with grass pollen rhinoconjunctivitis were enrolled in an 8-month double-blind, placebo-controlled trial of SLIT. Sixty-three patients were randomized to four groups and evaluated at the end of the study. One group received placebo (n = 16) and the other three groups (n = 47) received five grass pollen extracts according to three different induction regimens: regimen 1 starting with 3 IR tablets (n = 15), regimen 2 starting with 10 IR (n = 16) and regimen 3 starting with 30 IR (n = 16). The maintenance phase was made with sublingual-swallow drops at the same concentration of 300 IR/ml for all the patients. Adverse events were recorded on diary cards. RESULTS: During induction phase, 25/47 patients in the SLIT groups had adverse reactions in comparison to 2/16 patients in the placebo group (p < 0.05). The rate of adverse reactions was 33.3% (11.8-61.6) (95% CI) for regimen 1, 31.3% (11.0-58.7) for regimen 2, 43.8% (19.8-70.1) for regimen 3 and 12.5% (1.6-38.3) for placebo. Fifty-seven reactions were local reactions involving the oral region (54 SLIT, 3 placebo) and 13 were systemic reactions (all in the SLIT groups). 11/13 reactions were mild (gastrointestinal disorders, rhinoconjunctivitis), 1/13 consisted of moderate asthma and 1/13 consisted of severe abdominal pain. No urticaria, angioedema or life-threatening events were observed. CONCLUSIONS: These preliminary data showed that various induction regimens for SLIT are generally well tolerated and could allow a fast build-up phase of SLIT.

Relationship between bronchial responsiveness and clinical evolution in infants who wheeze: a four-year prospective study.

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 asthma from childhood to adulthood: the essential role of the attending physician in prevention and surveillance]. / L'asthme allergique de l'enfance à l'âge adulte: rôle essentiel du médecin traitant dans la prévention et la surveillance.

Asthma is a chronic lung disease that affects both children and adults. Recent data from several countries show that asthma morbidity and mortality are increasing. Despite international consensus statement like GINA, asthma is under-diagnosed and under-treated. A better management of asthmatic patient is needed. The General Practitioner has to play an important role in management program.

Diagnostic value of nasal provocation challenge with allergens in children.

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.

Repeatability of lung function tests during methacholine challenge in wheezy infants.

BACKGROUND: The repeatability of lung function tests and methacholine inhalation tests was evaluated in recurrently wheezy infants over a one month period using the rapid thoracic compression technique. METHODS: Eighty-one wheezy, symptom free infants had pairs of methacholine challenge tests performed one month apart. Maximal flow at functional residual capacity (VmaxFRC) and transcutaneous oxygen tension (Ptco2) were measured at baseline and after methacholine inhalation. Provocative doses of methacholine causing a 15% fall in Ptco2 (PD15 Ptco2) or a 30% fall in VmaxFRC (PD30 VmaxFRC) were determined. RESULTS: Large changes in VmaxFRC were measured from T1 to T2 with a mean difference between measurements (T2-T1) of 7 (113) ml/s and a 95% range for a single determination for VmaxFRC of 160 ml/s. The mean (SD) difference between pairs of PD30 VmaxFRC measurements was 0.33 (1.89) doubling doses with a 95% range for a single determination of 2.7 doubling doses. Repeatability of PD15Ptco2 was similar. A change of 3.7 doubling doses of methacholine measured on successive occasions represents a significant change. CONCLUSIONS: Baseline VmaxFRC values are highly variable in wheezy, symptom free infants. Using either VmaxFRC or Ptco2 as the outcome measure for methacholine challenges provided similar repeatability. A change of more than 3.7 doubling doses of methacholine is required for clinical significance.

Nasal cytology in rhinitis children: comparison between brushing and blowing the nose.

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-Grunwald-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.

Ability of new lung function tests to assess methacholine-induced airway obstruction in infants.

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.

[Efficacy of a powder inhaler (Turbuhaler) in moderate asthmatic crises in children]. / Efficacité d'un inhalateur de poudre (Turbuhaler) dans la crise d'asthme modérée de l'enfant.

The use of a metered dose inhaler can be difficult in children, and requires the juxtaposition of an inhalation chamber. Powder inhalers offer different means of administration and are simpler to use and can be easily carried in the pocket or in a school satchel. The aim of this study is to assess the use of a beta-2-mimetic powder inhaler (Bricanyl Turbuhaler) in children presenting with an exacerbation of asthma. Thirty children aged from 4 to 14 years were included in an open random study in parallel groups. After a baseline measure of pulmonary function, the children inhaled 500 microgram of powdered terbutaline, or with metered dose aerosol attached to a spacer device (Nebuhaler). A significant bronchodilatation was apparent in the two groups of children which was measured at 15 and 30 minutes after the inhalation of the drug (measures of peak flow and forced expiratory volume in one second and of specific airways resistance were made). The bronchodilator response was similar whatever the method of inhalation. Although the inspiratory flow is decreased in an exacerbation this work shows that it is possible to advise the use of a powder inhaler in children presenting with a moderate exacerbation of asthma.

Dissociation of symptom scores and bronchial hyperreactivity: study in asthmatic children on long-term treatment with inhaled beclomethasone dipropionate.

The aim of the study was to evaluate the effects of inhaled steroids (IS) on the improvement of clinical asthma symptoms and on the decrease in bronchial hyperreactivity (BHR). Twenty-four children with severe asthma were given 1,000 micrograms beclomethasone dipropionate (BDP) daily and compared with ten asthmatic control children. The study included the evaluation of daily clinical score, of exercise induced asthma, of bronchial obstruction (forced expiratory volume in 1 sec, FEV1), and of BHR at months 0, 1, 2-3, and 4-5 (M0, M1, M2-3, and M4-5). BHR was assessed by standardized inhaled carbachol provocation measuring plethysmographic specific airway resistance (SRaw). The carbachol dose causing a 40% decrease in specific conductance (SGaw) was determined (PD40 SGaw). Clinical scores decreased at M1 (P less than 0.01) and throughout the study. FEV1 increased at M1 (P less than 0.05), M2-3 (P less than 0.01), and M4-5 (P less than 0.05) compared to M0. PD40 SGaw only increased significantly at M1 and M2-3. No individual correlation was found between clinical scores and PD40 SGaw at any testing, or between the decrease of clinical scores and the decrease of BHR. We conclude that bronchoconstrictive challenge tests do not adequately assess the clinical efficacy of IS. In clinical practice non-specific BHR should be preferentially measured for diagnosing atypical forms of asthma.

A study on the reproducibility of specific bronchial provocation testing in children.

Bronchial provocation tests with housedust were carried out on thirty-five asthmatic children aged 4-13. Each patient was tested twice. Subjects were studied with two different doses of allergen: 1200 and 3600 micrograms. There was reproducibility in 80% of the seventy tests performed, allowing confirmation of the reliability of the test. Furthermore, reproducibility was better when lower doses of allergen were inhaled. The intensity of the bronchial response sometimes varied in the same subject. These variations were greater when the inhaled volume increased. Immediate and delayed reactions together and delayed reactions alone were frequent (60% of cases); this should therefore be taken into account when studying the reproducibility of specific bronchial provocation test.