The conundrum of wheezing and airway hyperreactivity in infancy

Oral prednisolone in the acute management of children age 6 to 35 months with viral respiratory infection-induced lower airway disease: a randomized, placebo-controlled trial

OBJECTIVE

To investigate the efficacy of oral prednisolone in virally induced respiratory distress. Study design Randomized, double-blind, placebo-controlled trial involving 230 children age 6 to 35 months in the emergency department. Each patient received either oral prednisolone (2 mg/kg/d) or placebo for 3 days.

RESULTS

The hospitalization rates were similar between the two groups. For admitted children (n=123), the median length of stay was 1 day shorter in the prednisolone group (2 vs 3 days, P=.060). The proportion of children requiring >or=3 days of hospitalization was 47.5% in the prednisolone group and 67.7% in the placebo group (P=.023). There was less need for additional asthma medication (18.0% vs 37.1%, P=.018) in the prednisolone group. The median duration of symptoms of respiratory distress was 1 day in the prednisolone group versus 2 days in the placebo group both among the hospitalized (P<.001) and nonhospitalized children (P=.006).

CONCLUSION

A 3-day course of oral prednisolone effectively reduced disease severity, length of hospital stay, and the duration of symptoms among children 6 to 35 months old with virally induced respiratory distress.

Recurrent wheezing in infants and young children and bronchial hyperresponsiveness: a perspective

Epidemiological studies report a 50% incidence of at least one wheezing episode in young children. If we can argue that 10% of children have asthma sometime during their pediatric years, it still leaves a significant percentage of children with an unexplained cause for their wheezing. Other recognized phenotypes of recurrent wheezing include young children exposed to excessive environmental tobacco smoke (ETS), while other infants wheeze recurrently following a significant episode of bronchiolitis. Bronchial hyperresponsiveness (BHR) is a universally recognized phenomenon of asthma, but its presence in young children with recurrent wheezing is not as well studied. Currently available studies demonstrates that BHR is also seen in young pediatric asthmatics, paralleling what is well recognized in adolescent or adult asthma. In those children with post-bronchiolitis wheezing, BHR appears to be present to a degree; while infants and young children exposed to ETS have increased BHR, as a group. If exaggerated BHR in recurrent wheezing children without asthma has the same inherent disadvantage as it does in asthmatic children, additional studies looking directly at this issue in a longitudinal fashion need to be designed. A hypothesis of BHR in non-asthmatic children is presented that could be studied prospectively.

Bronchiolitis, respiratory syncytial virus, and recurrent wheezing: what is the relationship?

Various follow-up studies of children hospitalized with bronchiolitis caused by respiratory syncytial virus have demonstrated that a significant proportion of infants (50%) have recurrent wheezing during childhood. Nevertheless, the relationship between these two entities, if any, has not been established. In order to explain this observation, several hypotheses have been proposed. The first suggests that some children could have an individual predisposition to bronchiolitis caused by respiratory syncytial virus and recurrent wheezing. The virus could be a marker of this condition, and the individual predisposition could in turn be related to an individual hypersensitivity to common allergens (atopy), airway hyperreactivity, or to some disorder related to pulmonary anatomy or physiology that was present before the acute episode of bronchiolitis. Another hypothesis proposes that respiratory syncytial virus could be directly responsible for recurrent wheezing. During an episode of bronchiolitis, the damage in the airway mucosa caused by the vital inflammatory response to infection contributes to sensitivity to other allergens or exposes irritant receptors, resulting in recurrent wheezing. For this review, we analyzed the studies that discuss these hypotheses with the purpose of clarifying the mechanisms for the important issue of recurrent wheezing in childhood.

Serum eosinophilic cationic protein may predict clinical course of wheezing in young children

Thirty eight children aged between 2 and 4 years with three or more episodes of wheezing were studied to evaluate the role of eosinophil inflammation and its relation to persistence of wheezing two years later. Serum eosinophilic cationic protein, total eosinophil count, total IgE, skin prick test, and clinical features were evaluated at visit 1. Two years later at a second clinical evaluation the children were separated into two groups: group 1, those with persistent wheezing (n = 20); group 2, those who had been asymptomatic over the past six months (transient wheezing) (n = 18). Mean (SEM) eosinophilic cationic protein at visit 1 was higher in group 1 than in group 2 (29.63 (5.16) v 14.42 (2.77) micrograms/l), and the probability of continuing wheezing at age 5 years was greater in children with values > or = 20 micrograms/l at visit 1 than in those with lower values (relative risk = 2.88, 95% confidence interval 1.42 to 5.87, p < 0.001). Eosinophil inflammation is present from the beginning of the disease in the children who are going to continue with wheezing at age 5 years. The measurement of serum eosinophilic cationic protein may help in evaluating which wheezing infants are going to continue with asthma in the future.

Nasopharyngeal eosinophil cationic protein in bronchiolitis: relation to viral findings and subsequent wheezing

A prospective 4-month follow-up of children hospitalized with bronchiolitis revealed that high concentrations of eosinophil cationic protein (ECP) in nasopharyngeal aspirates (NPA) are predictive of wheezing after bronchiolitis. In the 29 patients who received no anti-inflammatory therapy the median concentration of NPA ECP was 882 ng/g in those with physician-diagnosed wheezing (P = 0.02). The NPA ECP concentration of the whole study group of 88 children with and without subsequent hospital admissions for wheezing were 531 and 299 ng/g, respectively (P = 0.02). At entry the children with negative viral findings had significantly higher concentrations of respiratory tract ECP than those with positive viral findings (515 vs. 240 ng/g; P = 0.01). The concentration of ECP in respiratory secretions decreased significantly after bronchiolitis (P = 0.01) provided that no new viral or mycoplasmal infection occurred. NPA ECP values decreased in relation to time regardless of whether anti-inflammatory therapy was used or not. Children with high concentrations of respiratory tract ECP seemed to benefit from anti-inflammatory therapy with nebulized cromolyn sodium or budesonide; both drugs significantly decreased the number of subsequent physician-diagnosed bronchial obstruction (P = 0.0006), and they tended to decrease the number of hospital admissions for wheezing (P = 0.08). Our results suggest that high concentrations of ECP in respiratory tract secretions in children with bronchiolitis reflect the presence of eosinophilic inflammation also seen in asthma.

Eosinophil cationic protein in serum and nasal washes from wheezing infants and children

OBJECTIVE

To compare eosinophil counts and concentrations of eosinophil cationic protein (ECP) in serum and nasal wash fluid from wheezing infants and children with those from age-matched children without respiratory tract symptoms.

DESIGN

A case-control study of 71 children treated for wheezing and 59 control subjects in the University of Virginia Pediatric Emergency Department. The patients ranged from 2 months to 16 years of age. Eosinophil numbers and ECP concentrations were assessed in serum and nasal washes. Total serum IgE was measured and the radioallergosorbent test was used to measure IgE antibody to common inhalant allergens.

RESULTS

Among children less than the age of 2 years, markedly elevated levels of ECP (> 200 ng/ml) were measured in nasal washes from 9 (41%) of 22 wheezing patients and 1 (6%) of 17 control subjects (p < 0.03). None of these children had a positive radioallergosorbent test result for IgE antibody to common aeroallergens or a nasal smear containing 10% eosinophils. Few of the wheezing children under 2 years of age had either increased concentrations of total IgE or ECP in their serum or an elevated total blood eosinophil count. After the age of 2 years, the percentage of patients with nasal ECP levels greater than 200 ng/ml was also significantly higher in wheezing children than in control subjects (p < 0.001), and a positive correlation was observed between ECP concentrations in their nasal washes and other eosinophil responses (total blood eosinophil counts, serum ECP levels, and nasal eosinophil counts).

CONCLUSION

Increased concentrations of ECP were detected in nasal washes from wheezing infants and children, indicating that eosinophils may contribute to the pathogenesis of airway inflammation in some children who wheeze early in life.

Do lower respiratory tract infections in early childhood cause chronic obstructive pulmonary disease?

The hypothesis that lower respiratory tract infections (LRTI) in early childhood lead to chronic obstructive pulmonary disease (COPD) in late adult life has been difficult to test. However, a unique opportunity arose when records were discovered in the counties of Hertfordshire and Derbyshire, England, that contained information about childhood LRTI recorded 60 to 70 years ago. The lung function of some men still living in these counties was examined. In Hertfordshire men, bronchitis or pneumonia in infancy was associated with reduced mean FEV1, adjusted for age and height. In Derbyshire men, pneumonia before 2 yr of age was associated with a large and highly significant reduction in mean FEV1, adjusted for age and height. These findings were independent of smoking and social class. These data support a causal relationship between LRTI in early life and subsequent COPD.

Sequelae of respiratory syncytial virus infections. A role for intervention studies

The association between respiratory syncytial virus (RSV) infections in infancy and respiratory abnormalities later in life has been attributed both to a direct effect of the infection itself and to an inherent susceptibility. Observational studies do not allow a rigorous test of these hypotheses. Respiratory syncytial virus infection is universal in the first years of life and no uninfected control group exists. Randomized, controlled trials using new prophylactic agents such as vaccines or specific therapeutic agents will provide a powerful test of the relationship between RSV infection and long-term respiratory sequelae.

[Comparative study of nebulized sambutol against placebo in the acute phase of bronchiolitis in 33 infants aged 1 to 6 months]

BACKGROUND

The therapeutic role of bronchodilators in bronchiolitis remains controversial. The aim of this study is to evaluate the safety and the clinical response to nebulized salbutamol in infants with mild acute bronchiolitis.

PATIENTS AND METHODS

Thirty-three infants, aged 1 month to 5 months and 22 days (mean: 92.4 days) were included in the study. Patients received either nebulized salbutamol (0.15 mg/kg per dose: 16 infants) or a placebo (normal saline aerosol: 17 infants), delivered by an oxygen propellent, three times at intervals of 1 hour, as part of a double-blind randomized trial. Effect of treatment was evaluated by measuring respiratory and heart rate, clinical scores based on the degree of retraction and wheezing, and oxygen saturation. Clinical assessment was repeated 30 minutes after each nebulization. A nasopharyngeal swab was obtained for detection of respiratory syncytial virus (VRS) antigens by immunofluorescence assay in all patients.

RESULTS

Patients in the salbutamol group exhibited significantly greater improvement in respiratory rate (P = 0.01), accessory muscle score (P < 0.001) and wheezing score (P < 0.001). There was no significant difference in oxygen saturation between both groups. Infants treated with salbutamol exhibited a non-significant increase in heart rate after the three sprays; no other adverse effects were noted. VRS was identified in 78% of the children tested.

CONCLUSIONS

Salbutamol is safe and effective in relieving the respiratory distress of young infants with acute bronchiolitis. Our study confirms previous observations that infants younger than six months of age respond as well as older children when given three doses of nebulized salbutamol. Responders could not be differentiated from non responders by personal or family histories of atopy and VRS isolation. A longitudinal study could establish a correlation between response to bronchodilator therapy and later development of asthma.