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Childhood asthma. Rod Addis, Vanessa Kerai. Overview. Prevalence Aetiology Pathophysiology Clinical features Diagnosis Management <5s Management 5-12. Prevalence. Asthma is commonest in children - predominantly extrinsic. Childhood asthma affects up to 5% of children
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Childhood asthma Rod Addis, Vanessa Kerai
Overview • Prevalence • Aetiology • Pathophysiology • Clinical features • Diagnosis • Management <5s • Management 5-12
Prevalence • Asthma is commonest in children - predominantly extrinsic. • Childhood asthma affects up to 5% of children • Peak age of onset is 5 years. • More common in boys than girls (3:2) • 25% of asthmatic children have some restriction of physical activity.
Aetiology • Genetic predisposition - atopy is known to be inherited by a dominant gene on chromosome 11: • Atopic component in 40% of patients • Associated with eczema, fever or urticaria. • Raised IgE, eosinophilia, labile PEFR, known sensitivity to allergens • Infection: • Viral-induced wheeze occurs in some 20% of children • acute RSV bronchiolitis can cause a persistent asthma syndrome independent of a familial atopy or asthma • Passive smoking • Bronchial hyper-responsiveness
Disease progression/remission • In cases where episodes of asthma are infrequent, asthma will cease in adult life • Patients with frequent episodes of asthma or chronic asthma are more likely to suffer from life-long asthma • Risk factors for persisting asthma: • early age of onset and requiring frequent periods of hospital treatment • patients with ongoing eczema • patients with chronic lung abnormalities • smoking with asthma
Pathophysiology • Acute phase (minutes) • Bronchoconstriction (contraction of bronchial smooth muscle) • Late phase (mediated by mast cells and marcrophages + recruitment of further immune cells increasing inflammatory reaction) • Mucosal oedema • Increased secretion of mucus
Symptoms of an acute attack: expiratory wheeze SOB sometimes cough may be the only symptom symptoms worse at night most patients may feel chest tightness in the morning young children may vomit or have reduced appetite Signs of an acute attack: child unable speak or to walk due to breathlessness intercostal recession and use of accessory muscles exhausted wheeze with tachypnoea and tachycardia silent chest (severe presentation) Clinical features • Between attacks, the child may be asymptomatic • Peak flow - not reliable due to poor technique • Chronic asthmatic may have a Harrison's sulcus
Clinical features that increase the probability of asthma: More than one of the following symptoms especially if frequent, worse at night/early morning/after exercise/exposure to triggers etc. Wheeze Cough difficulty breathing, chest tightness Atopic disorder FH of atopic disorder/asthma Improvement in symptoms or lung function with adequate therapy Clinical features that lower the probability of asthma: Symptoms with URTI only no interval symptoms isolated cough in the absence of wheeze or difficulty breathing history of moist cough prominent dizziness, light-headedness, peripheral tingling repeatedly normal physical examination of chest when symptomatic normal PEFR/spirometry when symptomatic no response to a trial of asthma therapy clinical features pointing to alternative diagnosis Diagnosis*BTS/SIGN (May 2008). British Guideline on the Management of Asthma
high probability of asthma: start a trial of treatment review and assess response reserve further testing for those with a poor response low probability of asthma consider more detailed investigation and specialist referral intermediate probability of asthma if there is significant reversibility/if treatment trial is beneficial asthma is probable Treat as asthma, but aim to find the minimum effective dose of therapy. At a later point, consider a trial of reduction, or withdrawal, of treatment if there is no significant reversibility, and treatment trial is not beneficial, consider tests for alternative conditions Diagnosis II
Non-drug measures Avoiding house dust mites • Methods to reduce levels of house dust mites have not been proved to reduce symptoms of asthma.
Avoidance of other exacerbating factors • No evidence confirms that removing pets from the house helps children with asthma who have a pet allergy, but many experts still recommend this approach. • Cessation of smoking by parents can reduce the severity of their children's asthma.
Control of asthma is assessed against these standards: • Minimal symptoms during day and night • Minimal need for reliever drugs • No exacerbations • No limitation of physical activity • Normal lung function (FEV1 or PEF >80% predicted or best, or both).
A stepwise approach aims to: • Abolish symptoms as soon as possible • Optimise peak flow by starting treatment at the level most likely to achieve this.
Management <5 Step 1 • SABA Step 2 • Inhaled steroids if: • exacerbation of asthma in the last 2 years requiring oral steroids • using inhaled β2 agonists three times a week or more • symptomatic three times a week or more • waking one night a week *Titrate steroid dose to lowest dose at which effective treatment maintained • Leukotriene agonists if inhaled steroids not tolerated
Management <5 Step 3 • If taking inhaled steroid, add in leukotriene antagonist • If taking leukotriene antagonist, add inhaled steroid • If <2 proceed to Step 4 Step 4 • Refer to respiratory paediatrician
Management 5-12 Step 1 • SABA • Step 2 • Inhaled steroids if: • exacerbation of asthma in the last 2 years requiring oral steroids • using inhaled β2 agonists three times a week or more • symptomatic three times a week or more • waking one night a week *Titrate steroid dose to lowest dose at which effective treatment maintained • Leukotriene agonists if inhaled steroids not tolerated
Management 5-12 Step 3 • Add in LABA • good response • continue LABA • if there is benefit from LABA but control is still inadequate • continue LABA • increase inhaled steroid dose • if control still inadequate then go to step 4 • if no response to LABA • stop LABA • increase inhaled steroid • If control is still inadequate trial of other therapies: • leukotriene receptor antagonist • SR theophylline • If control still inadequate then go to step 4
Management 5-12 Step 4 • Increase dose of inhaled steroid Step 5 • Daily oral steroid (lowest dose which provides control) • Maintain high inhaled steroid • Respiratory peadiatrician r/v * Patients on long term steroid tablets >3/12 or requiring frequent courses of steroid tablets (3-4/yr) are at risk of systemic side effects. Monitor for general side effects of steroid use + specific monitoring of growth and screening for the development of cataracts
When to refer? • Diagnostic uncertainty • Symptoms present from birth • Excessive vomiting or posseting • Severe URTI • Persistent wet cough • Growth faltering • Family history of unusual chest disease • Unexpected clinical findings (e.g focal chest signs or dysphagia) • Failure to respond to conventional treatment • Parental anxiety.
Questions? Thank you