Relationship between Bronchial Responsiveness and Clinical Evolution in Infants Who Wheeze

Abstract

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.

Airway responsiveness: associated features in infants with recurrent respiratory symptoms

“…Their symptoms are likely to persist, and this may necessitate anti-asthmatic treatment. However, the routine measurement of AR during infancy is not feasible, and cut-off points for provocative concentrations or doses of methacholine determining clinical significance have not been established [25]. Therefore, the infants likely to present with increased AR have to be identified from their clinical characteristics.…”

“…The long-term outcome of a wheezy infant is also affected by a history of RSV bronchiolitis [26], a family history of asthma [27] or atopy [25], and smoke exposure in infancy [8,27]. There is little (and contradictory) evidence for the association of these characteristics with increased AR in infancy.…”

Update on the roles of distal airways in asthma

“…The authors concluded that patterns of wheezing prevalence and levels of lung function are established by age 6 yrs and do not appear to change significantly by age 16 yrs in children who start having asthma-like symptoms during preschool years. Distal airway obstruction related to early wheezing episodes may be easily demonstrated by age 5 yrs [62,63]. In a prospective study of infants who had had at least three episodes of wheezing, bronchial hyperreactivity at age 16 months was predictive of impaired lung function in children at age 9 yrs, strongly indicating early airway remodelling in infantile asthma [64].…”

Clinical assessment of asthma progression in children and adults

“…Recurrent wheezing in infants and young children is common and is made up of a heterogeneous group of conditions with different risk factors and prognoses. [2][3][4][5] Martinez et al 2 were among the first to characterize the various wheezing phenotypes in preschool children and to identify risk factors for persistence of asthma in school age. In this unselected birth cohort study, more than 1200 newborns were enrolled.…”

“…Wheezing is common in the first 3 years of life, yet only a fraction of all infants with wheeze will go on to develop childhood asthma. [2][3][4][5] It is also clear that many children with asthma will undergo remission in adolescence. [6][7][8][9][10][11][12] During adolescence, some boys undergo asthma remission because of enhanced lung and airway growth, whereas new-onset asthma can occur in girls with an increased body mass index.…”