Clinical Review - Managing asthma in children

The signs that point to an asthma diagnosis and a checklist for primary care follow up. By Dr Atul Gupta and Dr Madeleine Barnett.

Lung function tests may include use of a peak flow meter (Photograph: SPL)
Lung function tests may include use of a peak flow meter (Photograph: SPL)

Section 1: Epidemiology and aetiology

Asthma is a disease of the conducting airways, which in response to a wide range of exogenous and endogenous stimuli contract too much and too easily.

Interactions between multiple factors, including early allergen exposure, infections, diet, genetic predispositions, tobacco smoke exposure and pollution, result in airway inflammation, which limits airflow and leads to functional and structural changes in the airways in the form of bronchospasm, mucus hypersecretion, mucus plugs, mucosal oedema and smooth muscle contraction.1

Asthma is the most common chronic childhood disease in most industrialised countries. On average there are two asthmatic children in each UK classroom.1 The International Study of Asthma and Allergy in Childhood (ISAAC) found that the UK had among the highest prevalence, with 15% of children affected.

Sequential asthma studies have detected an increase in asthma over the past 25 years, although phase III of ISAAC has shown a fall in the prevalence.2 Higher prevalence exists with family history of atopy. The clear genetic component is inherited more strongly from the mother than the father. A child's risk of asthma is approximately double with one asthmatic parent.1

A child is admitted to a UK hospital with asthma symptoms every 17 minutes.1 An Australian study showed a 5% risk of death over 10 years post-intubation for asthma.3 Asthma UK, the Royal College of Physicians, and other bodies commenced the National Review of Asthma Deaths in February 2012 to gain an understanding of asthma deaths and assist prevention.1

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Aetiology
Airway inflammation in asthma is a multicellular process involving eosinophils, neutrophils, T helper 2 (Th2)-type CD4 lymphocytes and mast cells. This results in recruitment and activation of inflammatory cells in the respiratory mucosa following upregulation of endothelial adhesion molecules.

Asthma is classically driven by enhanced activity of Th2 cells, which induce IgE production, and promote eosinophilic airway inflammation and airway hyperresponsiveness.4 The relative contribution of these varies between children and between asthma episodes in the same child.


X-ray of a seven-year-old with asthma, showing hyperinflated lung fields (Photograph: Author image)

Classification
Asthma is a complicated disorder and evidence suggests that different patterns of illness have different underlying pathogenesis.

Viral associated wheeze: 30-50% of preschool children have at least one episode. Some children with atopic asthma start with a pattern of episodic viral wheeze; however, most of those with pure episodic viral wheeze outgrow their symptoms.4

Cough variant asthma: up to 5-10% of preand early school-aged children have had chronic cough without wheeze.4 Cough variant asthma associated with bronchial hyperresponsiveness or reversible airways obstruction does exist, but is rare. Isolated chronic cough without typical features of asthma suggests another diagnosis.4

Atopic asthma commonly presents as the school-aged child who complains of episodic wheeze, cough and shortness of breath, often with identifiable triggers and other signs of atopy. Up to 85% of school-aged children with asthma are atopic, classically associated with airway eosinophilia and mast cells.4,5

Section 2: Making the diagnosis

The first aim of the history and examination should be to try to establish whether the symptoms are consistent with asthma.5,6 The individual case history should focus on the frequency and severity of symptoms, including wheeze, nocturnal cough, exercise-induced symptoms and persistence of cough with colds, atopy and exposure to environmental factors, including allergens and tobacco smoke.

Symptom patterns in the past six months should be discussed, with a focus on details of the past four weeks.

Parental reports
The presence of wheeze consistently points to a diagnosis of asthma.5 Beware, however, parental reports of wheeze as interpretation of this clinical sign can vary from a change in respiratory rate to cough.5,6

In most children, diagnosis of asthma can be made by history and examination. A simple assessment of the extent of symptoms and variability of lung function using home peak expiratory flow rate (PEFR) recordings and symptom diaries over a month or so can be helpful.5,6

If the child does not respond to initial treatment or needs high doses of inhaled corticosteroids, some specific specialised tests may help to confirm the diagnosis and assess severity more objectively.

When the diagnosis is in doubt or where severe asthma persists despite treatments, referral to a specialist paediatric respiratory clinic is needed. A few patients need specialised lung function tests, bronchoscopy, pH study or CT scanning to rule out other conditions.

When to consider alternative diagnoses6

In the absence of

  • Symptoms between viral illness.
  • Wheeze.
  • Difficulty in breathing.
  • Wheeze on examination when symptomatic.
  • Improvement with trial of asthma therapy.
In the presence of
  • Isolated cough.
  • Normal PEFR with symptoms.
  • Normal spirometry with symptoms.
  • History of moist cough.
  • Prominent dizziness, peripheral tingling.

Section 3: Managing the condition

Management of asthma should include asthma education for patients and caregivers, avoidance of airborne allergens and irritant triggers, appropriate pharmacotherapy and acute asthma management plans.6

Pharmacotherapy
Therapy is based on treatment combinations to relax smooth muscle and to reduce airway inflammation.

The British Thoracic Society/Scottish Intercollegiate Guidelines Network (BTS/SIGN) guidelines have clearly defined age-appropriate pharmacological management of atopic asthma following a stepwise approach according to persistence, severity and frequency of symptoms, until control is achieved. Regular monitoring allows therapy to be stepped up or down to ensure the lowest level of treatment is used to control symptoms.6

Inhaled corticosteroids
Airway inflammation is a key component of asthma and inhaled glucocorticoids are the most effective anti-inflammatory treatments available. Considerable benefit for all major clinical outcome measures is seen with low and moderate doses (beclometasone to 400 microgram/day or fluticasone to 200 microgram/day). Beyond this, the dose-response curve is relatively flat.5,6

Although side-effects are unlikely at 400 microgram/day beclometasone or equivalent, they can occur at higher doses.

Practically, if a child seems to need higher doses of inhaled corticosteroid than those recommended by the manufacturer, questions that need to be considered are:5,6

  • Correct diagnosis?
  • Severity correctly reflected?
  • Avoidable triggers present?
  • Compliant and good technique?
  • Using steroid-sparing treatment?

Long-acting beta-2 agonists in asthma
For fiveto 12-year-old children, BTS/SIGN guidance advocates a trial of long-acting beta-2 agonists before increasing inhaled corticosteroids at a dose greater than 400 microgram/day.

These should be stopped if no benefit is achieved.6

Leukotriene receptor antagonists
Leukotriene receptor antagonists may provide improvement in lung function, a decrease in exacerbations and an improvement in symptoms.6

Anti-IgE monoclonal antibody (omalizumab)
NICE recommends omalizumab for patients over 12 years of age, within its licensed indication, as an option for the treatment of severe and unstable persistent allergic asthma.7

It should be commenced by physicians experienced in both allergy and respiratory medicine in a specialist centre. History and skin testing should confirm the IgE-mediated allergic nature of the condition.5,6

Smoking and asthma
Tobacco smoke is one of the strongest environmental risk factors for developing recurrent cough/wheezing or asthma. Maternal smoking during pregnancy results in impaired lung growth in the developing fetus.

Management of difficult to treat asthma in children
Therapy-resistant asthma with frequent use of short-acting beta-2 agonists and high steroid doses needs comprehensive assessment and meticulous exclusion of other causes of asthma-like symptoms. Lack of compliance and unrecognised adverse environmental influences should always be considered. The most common cause of poor response is non-compliance.

When to refer to a respiratory paediatrician
  • Diagnosis uncertainty.
  • Symptoms since birth or perinatal lung problem.
  • Excessive vomiting or posseting.
  • Severe URTI.
  • Persistent wet or productive cough.
  • Family history of unusual chest disease.
  • Faltering growth.
  • Nasal polyps.
  • Unexpected clinical findings, for example: focal signs, abnormal voice or cry, dysphagia, inspiratory stridor.
  • Failure to respond to conventional treatment (particularly inhaled corticosteroids above 400 microgram/day or frequent use of steroid tablets).
  • Parental anxiety or need for reassurance.

Section 4: Prognosis and follow up

Example checklist for follow up in primary care
Name                   Age   Date
Areas for discussion Details
Symptom score – for example, Childhood Asthma Control Test    
Exacerbations    
  • Limitation of activity – exercise-induced symptoms
  • Time off school/nursery
  • Symptom frequency
  • Woken from sleep
  • Rescue therapy use
  • Patient rating of symptoms (1–5)
  • Oral steroids use
  • Attendance at A&E
  • Admission to hospital
  • Recent lung function tests
  • Psychoso
   
 Current management    
 Previous management    
 Adherence to medicine    
 Review prescription refill frequency    
 Check inhaler technique       
 PEFR    
 Possession of individualised management plan            
 Use of management plan        
 Update/creation of management plan    
 Ensure adequate understanding of child and carer            
 Growth and height check and plotting    
 Smoking review and cessation advice    
 Assessment of triggers
  • Know triggers
  • Home visit concerns
  • Pets
   
 Other atopy
  • Hayfever
  • Eczema
   
 Change to management plan        
 Agreed review date        

Section 5: Case study

A 12-year-old with height and weight on the 25th centile, appropriate for mid-parental height, presented to clinic with increased asthma symptoms over recent months. His asthma control test score was nine out of 25. His PEFR was reduced and his recent lung function tests were suboptimal.

His activity levels were limited most of the time by his asthma and he was missing one day of school on average every two weeks, with symptoms occurring more than once per day. He was being woken from sleep feeling short of breath two to three times per week and required salbutamol one to two times per day.

He was using beclometasone regularly with good inhaler technique at a dose of 800 microgram/day. A previous montelukast trial had failed to give symptomatic improvement.

Initial diagnosis was at five years of age. He also has eczema and allergic rhinitis, and experiences worsening of his asthma-related symptoms on exposure to dust and cold. He and his family are non-smokers.

In the past month, he had attended A&E once after following his acute management plan at home appropriately. He required nebulised treatment and an oral course of steroids but was not admitted to the ward.

The management plan
As per the BTS/SIGN guidance, long-acting beta-2 agonists were added. This was done in combination with an inhaled steroid. A review date was set for one month's time.

On review, things were much improved, he no longer had limitation of activity, his attendance at school had improved and he was no longer waking at night. He had used his salbutamol inhaler twice since collecting the combination inhaler.

Chest CT scan of an eight-year-old severely asthmatic patient with evidence of small airways disease (Photograph: Author Image)

Section 6: Evidence base

Guidelines

Online

Information resource for parents and children, including chat rooms and information on educational holidays.

Provides a link to the updated guidelines on the management of asthma and the evidence behind the guidelines.

This website provides a five-question quiz to determine if a treatment plan is working.

Curriculum
This topic falls under section 15.8 of the RCGP curriculum, Respiratory Problems.

Reflect on this article and add notes to your CPD Organiser on MIMS Learning

CPD IMPACT: EARN MORE CREDITS

These further action points may allow you to earn more credits by increasing the time spent and the impact achieved.

  • Update your team on the latest asthma guidelines.
  • Make a poster for patients detailing the importance of compliance and technique in asthma.
  • Write an emergency protocol for asthma for use in your practice.

References
1. Asthma UK. 2012. www.asthma.org.uk. Accessed 14 May 2012.

2. International Study of Asthma and Allergies in Childhood. Lancet 1998; 351: 1225-32.

3. Triasih R, Duke T, Robertson CF. Arch Dis Child 2011; 96(8): 729-34.

4. Silverman M (editor). Childhood asthma and other wheezing disorders.

Second edition. London, Hodder Arnold, 2002.

5. Townshend J, Hails S, Mckean M. BMJ 2007; 335: 198-202.

6. British Thoracic Society, Scottish Intercollegiate Guidelines Network. British guideline on the management of asthma 2008: a national clinical guideline; updated January 2012. 7. NICE. Omalizumab for severe persistent allergic asthma. TA133. London, NICE,2007. www.nice.org.uk/nicemedia/pdf/TA133Guidance.pdf

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