Journal Article

Challenges in diagnosing asthma in children

Daines, Luke, Chisholm, Kendra, Turner, Steve

2024

Overview

European Respiratory Society (ERS), British Thoracic Society/ Scottish Intercollegiate Guideline Network (BTS/SIGN), National Institute for Health and Care Excellence (NICE), and Global Initiative for Asthma (GINA) Guideline (date published) ERS (March 2021) BTS/SIGN (July 2019) NICE (March 2021) GINA (June 2022) Number of objective tests required for diagnosis 2 1 - 2 † 2 2 Suggested order in which objective tests should be done 1 Spirometry 2 BDR (if spirometry abnormal) 3 FeNO 4 Diurnal PEF × 2 weeks/ challenge test 1 Spirometry + BDR 2 Variability tests/ tests for eosinophilic inflammation or atopy 1 Spirometry 2 BDR (if spirometry obstructed) 3 FeNO 4 PEF variability 1 Spirometry/ PEF with BDR 2 Diurnal PEF × 2 weeks/ exercise challenge test Age range covered by diagnostic algorithm 5-16 years ≤18 years ≤ 17 years 5-≤ 16 years What do the guidelines say about under 5s? “We did not include children aged <5 years in these guidelines, because diagnostic tests for asthma on young children are rarely performed” “Consider monitored initiation of treatment or watchful waiting according to the assessed probability of asthma” “Treat symptoms based on observation and clinical judgment, and review the child on a regular basis” “A probability-based approach using symptom pattern during and between respiratory infections may be helpful” Sensitivity Specificity of algorithm ‡ Not available Not available Sensitivity (69%) Specificity (67%) Sensitivity (42%) Specificity (90%) † Where there is a high probability of asthma (based on symptoms) spirometry before and after starting preventer treatment is recommended ‡ From a Swiss study of children referred to outpatient clinic.9 A second study, which used an epidemiological definition for asthma, concluded that the NICE diagnostic algorithm should not be used in children9 BDR=bronchodilator response. Box 1 Diagnosing asthma History taking Asthma includes recurrent episodes of cough and wheeze and difficulty in breathing A history of only cough or wheeze or difficulty in breathing is not consistent with asthma In children with asthma, their cough is typically dry and especially noted on exercise and a few hours after the child has gone to sleep Features suggesting an alternative diagnosis in children include: daily symptoms, symptoms present since birth, and a persistent wet cough6 Personal history of eczema, hayfever, or food allergies marginally increase the likelihood of asthma A first degree family history of asthma modestly increases the likelihood of asthma Exposures that cause symptoms (eg, exposure to second hand smoke) can be sought but these exposures are common in all children and typically increase the odds of asthma by twofold, and so should not carry much weight when making a diagnosis.10 Examination Examination is usually normal (unless the child is having an asthma exacerbation). Tests All four guidelines (and NHS England’s 2021 National Bundle of Care for Children and Young People with Asthma) recommend that a clinical diagnosis should be supported by objective testing, ideally before starting preventer treatment because this may affect test results. Usually done twice daily over a two week period Airway calibre variability Other tests Bronchodilator response Spirometry before and after inhaling a short acting beta agonist Level of reversible airway obstruction Airway challenge, eg, with methacholine Spirometry before and after inhaling increasing concentrations or doses of a chemical known to induce bronchospasm Level of airway reactiveness Exercise test Spirometry before, during, and after exercise Level of airway reactiveness to exercise These tests can be carried out in children under 5 but usually only in centres with expertise Spirometry Guidelines recommend spirometry as the primary diagnostic test for children.

• Publisher: British Medical Journal Publishing Group,BMJ Publishing Group LTD
• Subject: Airway management / Algorithms / Asthma / Asthma - diagnosis / Atopy / Auscultation / Bronchodilators / Bronchospasm / Child / Children / Children & youth / Cough / Diagnosis / Diagnostic tests / Diurnal / Eczema / Epidemiology / Failure to thrive / Families & family life / Food allergies / Humans / Leukocytes (eosinophilic) / Medical diagnosis / Methacholine / Nitric oxide / Parents & parenting / Passive smoking / Practice / Respiration / Respiratory tract infection / Spirometry / Thorax