Transcript Childhood asthma - Derby Gp Specialty Training Programme

Childhood asthma
Rod Addis, Vanessa Kerai
Overview
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Prevalence
Aetiology
Pathophysiology
Clinical features
Diagnosis
Management <5s
Management 5-12
Prevalence
• Asthma is commonest in children •
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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
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
• 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)
Diagnosis
*BTS/SIGN (May 2008). British Guideline on the Management 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
• 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, lightheadedness, 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
• intermediate probability of
asthma
– if there is significant
reversibility/if treatment
trial is beneficial asthma is
probable
• Treat as asthma, but aim
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• low probability of asthma
– consider more detailed
investigation and specialist
referral
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.
Avoidance of other exacerbating
factors
• No evidence confirms that removing pets from
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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
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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?
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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