Diagnosing asthma in school-going children

The diagnosis of asthma in school-aged children range from being very simple to complex. It is simple when there are classical asthma symptoms (wheeze and shortness of breath, with evidence of reversibility on spirometry). However, it can also be complex requiring the need for tests of bronchial hyper-responsiveness (BHR) which is neither 100% specific or sensitive. 

 

There are currently several major guidelines including GINA,¹ the USA National Asthma Education and Prevention Program (NAEPP),² and that from the European Respiratory Society (ERS),³ and the ERS/ATS standards for interpreting routine lung function tests.⁴ However, while these guidelines have commonalities, there are substantial difference in several aspects that include the definition of bronchodilator reversibility, use of fractional exhaled nitric oxide (FeNO) and its cut-offs and other confirmatory tests. 

 

While measuring FeNO levels is attractive and increasingly available, it adds an additional cost of above current universal practice. In the interpretation of studies involving FeNO and its levels in patients, clinicians need to be cognisant of the many factors that influence these levels above and beyond clinical disease.⁵For example, using the ATS recommended cut-off to define presence of airway eosinophilic inflammation in children (levels >35 ppb in children aged ≤12 years; >50 ppb when aged >12 years)⁶ a systematic review found five studies in which at least 5% of healthy people from non-Caucasian ethnic groups had FeNO results above the age-specific inflammatory ranges.⁷The 4 major documents regarding the use of FeNO in the diagnosis of asthma where there are similarities and also substantial discrepancies.^8-10

 

This lecture will discuss the similarities and differences between the major guidelines with respect to the diagnosis of asthma in school-aged children, based on (a) symptoms and response to treatment, (b) confirmatory tests (spirometry, peak flow and BHR) and, (c) the role and controversies of using FeNO. Lastly a clinician’s practical approach will be presented. 

 

References

1 Global Strategy for Asthma Management and Prevention. 2024 GINA Report 2024.

2 Cloutier MM, Baptist AP, Blake KV, et al. 2020 Focused Updates to the Asthma Management Guidelines: A Report from the National Asthma Education and Prevention Program Coordinating Committee Expert Panel Working Group. J Allergy Clin Immunol 2020; 146: 1217-70.

3 Gaillard EA, Kuehni CE, Turner S, et al. European Respiratory Society clinical practice guidelines for the diagnosis of asthma in children aged 5-16 years. Eur Respir J 2021; 58: 2004173.

4 Stanojevic S, Kaminsky DA, Miller MR, et al. ERS/ATS technical standard on interpretive strategies for routine lung function tests. Eur Respir J 2022; 60: 2101499.

5 Collaro AJ, Chang AB, Marchant JM, et al. Developing Fractional Exhaled Nitric Oxide Predicted and Upper Limit of Normal Values for a Disadvantaged Population. Chest 2023; 163: 624-33.

6 Dweik RA, Boggs PB, Erzurum SC, et al. An Official ATS Clinical Practice Guideline: Interpretation of Exhaled Nitric Oxide Levels (FENO) for Clinical Applications. Am J Respir Crit Care Med 2011; 184: 602-15.

7 Blake TL, Chang AB, Chatfield MD, et al. Does Ethnicity Influence Fractional Exhaled Nitric Oxide in Healthy Individuals?: A Systematic Review. Chest 2017; 152: 40-50.

8 Wang Z, Pianosi P, Keogh K, et al. The clinical utility of fractional exhaled nitric oxide (FeNO) in asthma management. Comparative Effectiveness Review No. 197. AHRQ Publication No 17(18)-EHC030-1-EF Rockville, MD: Agency for Healthcare Research and Quality  2018.

9 SIGN. British guideline on the management of asthma. http://www sign ac uk/pdf/SIGN153 pdf 2016.

10 Bland JM. The tyranny of power: is there a better way to calculate sample size? BMJ 2009; 339.