What must we treat in childhood asthma: symptoms and/or abnormal function?

Abstract

The goals of asthma treatment are to eliminate symptoms, prevent acute attacks, maintain as normal a lifestyle as possible, avoid drug side-effects, and normalize lung function. Treatment must therefore be based on recognizing symptoms of asthma, accurately characterizing severity of asthma and perceiving increasing severity during an acute attack. Criteria are necessary to provide instructions for increasing reliever medications during acute attacks as well as for appropriate preventive medications in long term management. Are symptoms or lung function measurements the most appropriate for use in these situations? Lung function tests provide an objective measure of the compromised airway in asthma. The U.S. consensus document on guidelines for asthma management states “pulmonary function tests are essential for the diagnosis of asthma and for assessing the severity of asthma in order to make appropriate therapeutic recommendations”1. However, Drummond et al.2 have reported that self-monitoring with peak flow meters did not give any additional advantage to management on symptoms alone. Peak flow variation is associated with asthma and falls in peak flow occur before perception of symptoms in some asthmatics, but it is clear that a careful history and physical examination will provide considerable information. The historic information which should be obtained at each visit is only accurate if specific questions are asked. One needs to be aware of gender bias as some cultural groups may unintentionally underrate symptoms as has been reported in Swiss girls3. At least, 30 % of infants will wheeze but only l/3rd of these will go on to have continuing asthma4. Adolescence is another time when denial of symptoms or fake symptoms are more likely to be present. In this situation, objective measures are more useful for confirming the severity of asthma. Lung function measurements should be seen as an adjunct to clinical assessment and not as a substitute. Some children with intermittent life-threatening attacks of asthma can have completely normal lung function between attacks. Other children may have apparently bizarre measurements due to unsatisfactory equipment, poor technique or inappropriate analysis of results. When it is possible for a child to perform reliable lung function maneuvers during a clinical examination, the measurements are used for: 1. How often does the child wake at night with cough and/or wheeze? 2. How often does the child need to use medication for cough and/or wheeze on waking in the morning? 3. How often does the child limit sport or play due to cough, wheeze or breathlessness? 4. How often are additional doses of bronchodilator used? 5. How long does a metered dose inhaler last? 1. excluding alternative diagnoses - upper airway disease, non-bronchodilator responsive causes of airway obstruction and rare restrictive lung diseases; 2. assessing severity of asthma; 3. assessing response to treatment. They may also help identify poor compliance with therapy; 4. identifying environmental factors that may trigger asthma attacks. This may include the rare bronchoconstrictor response to some MDI's; 5. educating parents and families to better perceive the degree of airway obstruction; and monitoring early deterioration, to allow expeditious intervention and prevention of severe life-threatening attacks.