ABC of one to seven. Bronchial asthma.
Authors: H B Valman
Journal: BMJ (1993)

H B ValmanThe symptoms of bronchial asthma are caused by narrowing of the bronchi >--_ and bronchioles by mucosal swelling and contraction of the muscle in their walls, with viscid secretion obstructing the lumen.The muscle contraction >>i 0l is reversible by bronchodilators which belong to two main groups:13 adrenoceptor stimulants such as salbutamol or antimuscarinic drugs such as ipratropium bromide.In most children with bronchial asthma there are no symptoms or abnormal signs between acute attacks, and lung function tests, unless performed after exercise, are normal.Asthma is the most common, chronic disease of childhood and it affects about 10% of schoolchildren.About 80/ of children with asthma have the first symptoms before the age of 5 years and at least half will stop having attacks when they become adults.During the past 20 years new prophylactic drugs and better methods of administering them have resulted in many children with asthma being cmpletely free of symptoms.Treatment needs to b eiwdrglrya the severity fluctuates and the most suitable preparation changes as the Diagnosis Bronchial asthma should be suspected if there is recurrent cough, wheezing, or shortness of breath, especially after exercise or during the night.Improvement with a bronchodilator is helpful evidence.The first Symptoms of bronchialaattack may occur at any age, but to avoid many children with an acute lower | Symptoms of bronchial asthma respiratory tract infection being labelled as having asthma it is preferable to * Recurrentcough wait until three episodes have occurred within a year before confirming the * Wheezing diagnosis.There is no clinical or laboratory method of distinguishing * Shortness of breath between acute bronchial infection and asthma.Rhonchi may be heard in the Exacerbation of symptoms after exercise chest during and between attacks of asthma, but there may be no abnormal signs despite repeated examinations.Recurrent night cough may be the * Improvement with a bronchodilator only feature, and the absence of night cough is the best evidence that treatment is adequate.The length of absences from school, extent of poor growth and chest deformity, as well as the number of hospital admissions give an indication of the severity of the problem.Details of previous drug treatments may help to avoid the repetition of failures. AssessmentA detailed history should be taken of exposure to household pets or other animals which may belong to friends or relatives.Severe symptoms or hay fever at a particular time of the year may incriminate pollen.Skin tests tend to give negative results under the age ot 5 years and also when the child is taking steroids.The results may be helpful in avoiding exposure to allergens, but the long term effects of attempts at desensitisation are unknown.Identification of a specific allergen rarely has an effect on management, but exposure to tobacco smoke is associated with an increase in symptoms and should be avoided.The single most useful test is the peak flow reading, which can be measured using the low range (30-370 /min) mini-Wright peak flow meter.Normal ranges are related to the height of the child.In asthma peak flow