Dutch study in question
SIGN guidelines on asthma
In children with mild, intermittent wheeze and other respiratory symptoms which occur only with viral upper respiratory infections (colds), it is often reasonable to give no specific treatment and to plan a review of the child after an interval agreed with the parents/carers
The choice of treatment (for example, inhaled bronchodilators or corticosteroids) depends on the severity and frequency of symptoms. Although a trial of therapy with inhaled or oral corticosteroids is widely used to help make a diagnosis of asthma, there is little objective evidence to support this approach in children with recurrent wheeze. It can be difficult to assess the response to treatment, as an improvement in symptoms or lung function may be due to spontaneous remission. If it is unclear whether a child has improved, careful observation during a trial of withdrawing the treatment may clarify whether a response to asthma therapy has occurred. Spirometry and reversibility testing In children, as in adults, tests of airflow obstruction, airway responsiveness and airway inflammation may provide support for a diagnosis of asthma.16, 48 However, normal results on testing, especially if performed when the child is asymptomatic, do not exclude a diagnosis of asthma.50 Abnormal results may be seen in children with other respiratory diseases. Measuring lung function in young children is difficult and requires techniques which are not widely available. Above five years of age, conventional lung function testing is possible in most children in most settings. This includes measures of airway obstruction (spirometry and peak flow), reversibility with bronchodilators, and airway hyper-responsiveness.
Most children under five years and some older children cannot perform spirometry. In these children, offer a trial of treatment for a specific period. If there is clear evidence of clinical improvement, the treatment should be continued and they should be regarded as having asthma (it may be appropriate to consider a trial of withdrawal of treatment at a later stage). If the treatment trial is not beneficial, then consider tests for alternative conditions and referral for specialist assessment
The relationship between asthma symptoms and lung function tests including bronchodilator reversibility is complex. Asthma severity classified by symptoms and use of medicines correlates poorly with single measurements of forced expiratory volume in one second (FEV1 ) and other spirometric indices: FEV1 is often normal in children with persistent asthma.50, 51 Serial measures of peak flow variability and FEV1 show poor concordance with disease activity and do not reliably rule the diagnosis of asthma in or out.51 Measures of gas trapping (residual volume and the ratio of residual volume to total lung capacity, RV/TLC) may be superior to measurements of expiratory flow at detecting airways obstruction especially in asymptomatic children.50, 52 A significant increase in FEV1 (>12% from baseline)53 or PEF after bronchodilator indicates reversible airflow obstruction and supports the diagnosis of asthma. It is also predictive of a good response to inhaled corticosteroids (ICS).54 However, an absent response to bronchodilators does not exclude asthma.55
Good background on wheeze
The diagnosis and the process by which the diagnosis is made should be documented in the patient’s notes.
The diagnostic process is outlined in the BTS/SIGN guideline, figure 1 for children and in figure 2 for adults, and consists of:
• history and clinical examination
• objective tests if the clinical diagnosis is uncertain and
• response to treatment given in accordance with the BTS/SIGN treatment steps.
The diagnosis is not a one time event and may need to be reviewed, particularly in younger children.