Association of wheezing phenotypes with fractional exhaled nitric oxide in children

Current and future management of the young child with early onset wheezing

PURPOSE OF REVIEW

In this review, we discuss current thinking in relation to available guidelines for the care of preschool-aged children with recurrent wheezing, while highlighting the gaps in our knowledge and discussing changes that could occur over the next 5 years.

RECENT FINDINGS

The Asthma Predictive Index as well as allergen-specific IgE, peripheral eosinophil count and exhaled nitric oxide are perhaps underutilized sources of information that can assist in predicting progression to asthma and response to therapies. Inhaled corticosteroids and leukotriene receptor antagonists decrease impairment and exacerbation frequency in wheezing children but are not disease modifying. Macrolides may be useful during acute wheezing episodes for preventing progression to more severe symptoms. Monoclonal antibodies targeting IgE and TH2 cytokines have been successful in trials of adults and older children with asthma, but trials in younger children are needed.

SUMMARY

Establishing the phenotype and endotype of young wheezing children can be useful for prognostication of future asthma risk as well as for selection of the most appropriate treatment. Primary asthma prevention strategies are needed during the critical developmental window in early life prior to the onset of irrecoverable loss of lung function.

Exhaled nitric oxide as a diagnostic tool for wheezing in preschool children: A diagnostic accuracy study

BACKGROUND

Airways inflammation may precede pulmonary dysfunction in wheezing individuals. The fraction of exhaled nitric oxide (FENO) has been described as a useful method for wheezing diagnosis in children, however, its application requires evidence. This study aimed to determine the accuracy of FENO in identifying wheezing in preschoolers.

METHODS

A cross-sectional study was carried out with children from 3 to 5 years old, from Brazilian day care centers and public schools. They were evaluated by FENO measurement through the single breath method, and by ATS-DLD-78-C questionnaire that is used as a gold standard to phenotype wheezing patterns.

RESULTS

The sample consisted of 243 non-wheezing children, 118 non-recurrent wheezing and 62 recurrent wheezing. The means of FENO and confidence intervals of 95%, were 5.4 (CI 95%, 5.2-5.6); 7.5 (CI 95%, 6.9-8.2) and 11.2 (CI 95%, 9.6-12.7), respectively. The sensitivity, specificity, positive and negative predictive FENO values in the 6 parts per billion (ppb) cut-off point that best diagnosed wheezing of non-wheezing children, were: 65.5%, 84.3%, 75.6% and 76.7%, respectively, with an area under the curve (AUC) = 0.77. At 10 ppb, the best cut-off points for differentiating recurrent wheezing of non-recurrent wheezing were: 56.4%, 81.3%, 61.4%, 78.0%, respectively, with an AUC = 0.69. The post-test probability for each FENO cut-off points was increased by 33% for wheezing and 20% for recurrent wheezing diagnosis when associated with clinical examination.

CONCLUSION

FENO can provide a reliable and accurate method to discriminate the presence and type of wheezing in preschoolers with 92% of acceptable in this study population.