Childhood asthma Rod Addis, Vanessa Kerai

Overview Prevalence Prevalence Aetiology Aetiology Pathophysiology Pathophysiology Clinical features Clinical features Diagnosis Diagnosis Management <5s Management <5s Management 5-12 Management 5-12

Prevalence Asthma is commonest in children - predominantly extrinsic. Asthma is commonest in children - predominantly extrinsic. Childhood asthma affects up to 5% of children Childhood asthma affects up to 5% of children Peak age of onset is 5 years. Peak age of onset is 5 years. More common in boys than girls (3:2) More common in boys than girls (3:2) 25% of asthmatic children have some restriction of physical activity. 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: 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: 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 Passive smoking Bronchial hyper-responsiveness Bronchial hyper-responsiveness

Disease progression/remission In cases where episodes of asthma are infrequent, asthma will cease in adult life 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 Patients with frequent episodes of asthma or chronic asthma are more likely to suffer from life-long asthma Risk factors for persisting 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) 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) Late phase (mediated by mast cells and marcrophages + recruitment of further immune cells increasing inflammatory reaction) –Mucosal oedema –Increased secretion of mucus

Clinical features Symptoms of an acute attack: 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: 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) Between attacks, the child may be asymptomatic Peak flow - not reliable due to poor technique Chronic asthmatic may have a Harrison's sulcus

Diagnosis * BTS/SIGN (May 2008). British Guideline on the Management of Asthma Clinical features that increase the probability of asthma: 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 Wheeze Cough Cough difficulty breathing, difficulty breathing, chest tightness chest tightness Atopic disorder Atopic disorder FH of atopic disorder/asthma FH of atopic disorder/asthma Improvement in symptoms or lung function with adequate therapy Improvement in symptoms or lung function with adequate therapy Clinical features that lower the probability of asthma: 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 II high probability of asthma: –start a trial of treatment –review and assess response reserve further testing for those with a poor response reserve further testing for those with a poor response low probability of asthma low probability of asthma –consider more detailed investigation and specialist referral intermediate probability of asthma 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

Non-drug measures Avoiding house dust mites Methods to reduce levels of house dust mites have not been proved to reduce symptoms of asthma. 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. 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. 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 symptoms during day and night Minimal need for reliever drugs Minimal need for reliever drugs No exacerbations No exacerbations No limitation of physical activity No limitation of physical activity Normal lung function (FEV1 or PEF >80% predicted or best, or both). Normal lung function (FEV1 or PEF >80% predicted or best, or both).

A stepwise approach aims to: Abolish symptoms as soon as possible Abolish symptoms as soon as possible Optimise peak flow by starting treatment at the level most likely to achieve this. 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 β 2 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 β 2 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 Diagnostic uncertainty Symptoms present from birth Symptoms present from birth Excessive vomiting or posseting Excessive vomiting or posseting Severe URTI Severe URTI Persistent wet cough Persistent wet cough Growth faltering Growth faltering Family history of unusual chest disease Family history of unusual chest disease Unexpected clinical findings (e.g focal chest signs or dysphagia) Unexpected clinical findings (e.g focal chest signs or dysphagia) Failure to respond to conventional treatment Failure to respond to conventional treatment Parental anxiety. Parental anxiety.

Questions? Thank you