Asthma in children:diagnostic and management dilemmas

Practice nurses undertake the lion’s share of asthma management in primary care and need to understand the diagnostic and management issues presented by asthma in childhood, which are very different to those posed by asthma in adults

Asthma in children can be challenging to diagnose and to manage. Parents or carers (and even, on occasions, clinicians) may fail to recognise the symptoms and signs, and misconceptions surrounding treatment abound. This article gives an overview of the diagnosis and management of stable, childhood asthma in line with the latest BTS and SIGN guidelines, published last month.¹

SYMPTOMS AND SIGNS

Asthma in children causes one or more of the following:

• Wheezing
• Cough
• Difficulty breathing
• Chest tightness.

Wheezing in association with viral upper respiratory tract viral infection (URTI) is the commonest clinical pattern of asthma in children, particularly in the under 5s. Wheezing is common; 26% of infants in one study had had at least one episode by the age of 18 months.²

Wheeze has been defined as: ‘High pitched whistling sounds usually in expiration and associated with increased work of breathing, but which can also sometimes be heard in inspiration.’³

The term is often used imprecisely. Many parents do not understand what is meant by it, or use it to describe other respiratory noises, such as stridor.

Cough in asthma is typically dry and usually worse at night and/or first thing in the morning. It can be provoked by exposure to certain specific triggers, such as cats, horses or other allergens, and on exercise, laughing and while experiencing strong emotion.

Difficulty breathing and chest tightness can usually be described by older children, but this is not true of younger children. The use of accessory muscles of respiration during an acute episode is an important clinical sign.

Small children have difficulty somatising symptoms; they may well describe chest tightness as ‘tummy ache’.

DIAGNOSIS

Asthma is diagnosed clinically. As yet there is no definitive test for asthma. Investigations such as lung function testing, when these are appropriate, provide supporting evidence for the clinical diagnosis.

In children the diagnosis relies on recognition of the characteristic pattern of symptoms that make asthma a more, or less likely diagnosis. (Table 1) However, it is vital to bear in mind that, while asthma is common, there are other causes for these symptoms and it is important that they are not missed. (Table 2) An incorrect diagnosis of asthma can also have consequences – for later employment, or life insurance – and if there is doubt a second opinion is necessary. If in any doubt – refer!

The initial assessment of a child with suspected asthma should focus on:

• Key clinical features in the history and examination
• Careful consideration of alternative diagnoses.

This should enable the child to be placed into one of three categories of probability:

• High – diagnosis of asthma is likely
• Low – a condition other than asthma is likely
• Intermediate – diagnosis uncertain.

Figure 1, from the BTS SIGN guideline,¹ summarises the approach to diagnosis in these three categories.

In all cases, the basis on which a diagnosis of asthma is suspected must be recorded in the medical records.

DIAGNOSTIC TESTS

Spirometry is widely available in general practice and most children over the age of about 5 years can perform the test. There are however some important caveats:

• Spirometry is only valid if it is properly performed and interpreted by an adequately trained person
• Reference (predicted) values for lung function parameters in children are less robust than for adults, making interpretation difficult
• Abnormal spirometry does not diagnose asthma and is a feature of a number of other respiratory diseases
• ‘Normal’ lung function does not rule out asthma.

Asthma is a variable condition. A ‘one-off’ lung function test performed when a child is asymptomatic may be normal. An older, ‘sporty’ child with exercise induced symptoms may well have above predicted lung function when tested in the surgery.

Peak expiratory flow rate (PEFR) monitoring can be helpful, but remember that:

• PEFR, like spirometry, is effort dependent and results are only as good as the effort put into performing them
• Frequent or prolonged home monitoring is unlikely to be accurately complied with.

Reversibility testing will support a clinical diagnosis of asthma – but an absent response does not exclude it!

Chest X-ray is not necessary for the initial diagnostic work-up.

PHARMACOLOGICAL MANAGEMENT

Children are not little adults. Their management differs from adults and varies with the age of the child.

The wheezy infant and preschool child

The majority of children below the age of 2 years who only wheeze with URTI and have no interval symptoms will be free of recurrent respiratory symptoms by the time they go to school. A minority will go on to wheeze in response to other triggers, will experience symptoms between acute episodes, and are less likely to ‘grow out of it’. As a general rule, the earlier the onset of wheeze the better the prognosis, although the co-existence of atopic conditions, such as eczema, increases the risk of the child going on to develop asthma.

Preschool, wheeze can usefully be described as falling into two groups, based on the history:

• Episodic viral wheezing
• Multiple trigger.³

These categories guide treatment, but can change over time and each child needs to be constantly reassessed.

Episodic viral wheezing should be treated intermittently, initially with an intermittent bronchodilator - β2 agonist or anticholinergic.^1,3 If this fails to control symptoms then intermittent leukotriene receptor antagonists (LTRA), inhaled corticosteroids (ICS), or both, are the next option.¹ Mild symptoms with minimal respiratory distress may require no treatment at all.

The LTRA montelukast, taken at the onset of a URTI and continued for a minimum of a week or until the child is clinically better, can be effective, particularly in the 2-5 year age group.^4-6 The role of ICS in treating and preventing episodic viral wheeze is more controversial. Currently there is no evidence to support the use of intermittent ICS at licensed doses but a recent clinical review paper suggests that a trial of 6-8 weeks of regular ICS could be justified in children with severe episodic wheeze who require repeated admission or who have prolonged disruptive symptoms at home.³ In some cases, interval symptoms may have been underappreciated and an ICS trial might reveal this. It is important to review and discontinue the treatment if there is no benefit, and where benefit is demonstrated regular attempts to reduce the dose should be made. The potential adverse effect of ICS on growth and adrenal function need to be borne in mind.

Oral prednisolone should not be used for acute episodes of viral wheezing if the child is well enough to remain at home. Its use has also been questioned for children admitted to hospital.^7,8

Multiple trigger wheezing: There is currently very little evidence to guide management of this group. A pragmatic approach is suggested in Box 13

The school age child

The aims of asthma management are:¹

• No daytime symptoms
• No night-time waking due to asthma
• No need for rescue medication
• No asthma attacks
• No limitations on activity, including exercise
• Normal lung function (FEV1 and /or PEFR > 80% of predicted or best)
• Minimal side effects from medication.

Mild, intermittent asthma should be treated with a short-acting β2 agonist prescribed as necessary, not regularly. The prescription of more than one inhaler a month should trigger urgent review of the child’s asthma control and consideration of the need for regular preventer therapy.

Introduction of preventer therapy: ICS is the recommended first line preventer treatment in adults and children.¹ The safety profile of ICS, at recommended doses, is good. They should be considered for children with any features of poorly controlled asthma:

• Short-acting β2 agonist use three times a week or more
• Symptomatic three times a week or more
• Waking one night a week.

They should also be considered for children who have had an asthma attack requiring oral corticosteroids in the previous 2 years.

The starting dose should be appropriate to the severity of the presentation. There is no benefit to starting at a high dose and stepping down. A reasonable starting dose for a 5-12 year old is 200mcg beclometasone dipropionate (BDP) a day, or equivalent, in a divided dose twice daily.¹ Over 12 years a higher starting dose, e.g. 400mcg BDP a day, can be considered. When asthma control is achieved the dose should be titrated down to the lowest dose that maintains control.

Corticosteroids have had a bad press. There are alternative preventer therapies if parents are adamant that they will not give their child ICS and you are unable to persuade them, although these are generally less effective:

• LTRA
• Sodium cromoglycate and nedocromil sodium.

Add-on therapy: Some children will remain inadequately controlled on ICS. Check that the child has adequate inhaler technique and adherence to ICS therapy before escalating therapy. The first line add-on therapy is a long-acting β2 agonist (LABA). These should not be given as monotherapy and should only be used in addition to ICS.

There are no hard and fast rules about the dose of ICS at which a LABA should be added, but some patients benefit more from addition of a LABA than from escalation of their ICS dose. In under-12s LABA should be considered before going to 400mcg BDP a day.¹ If the response to LABA addition is suboptimal then consideration can be given to increasing the ICS dose to 400mcg BDP a day, if the child is not already taking this. In children over 12 years consider increasing the ICS dose to 800mcg BDP a day.

Continuing poor control occurs in a minority of children despite:

• Adequate ICS dose
• LABA
• Good inhaler technique
• Adherence to therapy.

At this stage the child should be referred for a specialist opinion.

Diagrams of the stepwise approach to the management of childhood asthma are available on pages 10 and 11 of the Quick Reference Guide to the BTS SIGN guideline: https://www.brit-thoracic.org.uk/guidelines-and-quality-standards/asthma-guideline/

INHALERS

A common reason for poor asthma control is poor inhaler technique.

Under the age of 5 years children are unable to consistently generate sufficient inspiratory flow to use a dry powder inhaler (DPI), or reliably hold their breath. They will only be able to use a pressurised metered dose inhaler (pMDI) with a spacer. Infants need a spacer with a facemask until they can reliably breathe in and out through the mouthpiece.

pMDI and spacer is the preferred method of delivering ICS at all ages. Local side effects are reduced and a consistent dose delivered to the lungs. Although bulky and not very portable a spacer can be kept at home for twice daily use.

Over the age of about 5 years – although this is very variable – children can begin to be taught to use a small, portable DPI. Some DPIs also have dose counters, enabling the parents to keep a check on the child’s inhaler use.

Breath activated pMDIs are easy to use and suitable for older children who can be taught to inhale at the slow, steady pace necessary for good lung deposition of the aerosol. A pMDI alone should be reserved for the child in their late teens (if at all). They are the cheapest inhaler device, but are also the most difficult to use properly.

In all cases inhalers should only be prescribed after the child has been taught and has demonstrated good technique. Technique should be checked at every visit by a competent, appropriately trained health professional.

MONITORING, EDUCATION AND SELF-MANAGEMENT

All children with asthma need to be reviewed at least an annually. The factors to be monitored include:

• Symptom score, e.g. Childhood Asthma Control Test, Asthma Control Questionnaire
• Attacks, oral corticosteroid use, time off school or nursery
• Inhaler technique
• Growth (height and weight centile)
• Possession and understanding of a self-management plan – their personalised asthma action plan
• Exposure to tobacco smoke.

Parental smoking is a major factor in the development of infant wheezing and a major risk factor for hospital admission. ‘Not smoking in front of the children’ does not confer sufficient protection.9, 10 Parents (and other cares) need firm, but non-judgemental advice and support to quit.

All people with asthma should be given a written, personalised asthma action plan (PAAP).¹ There is ample evidence that self-management education incorporating a written PAAP improves health outcomes:

• Reduced emergency visits – including unscheduled appointments, A&E attendance and hospital admissions
• Improved markers of asthma control.

An example of a PAAP is available from Asthma UK http://www.asthma.org.uk/advice-personal-action-plan?gclid=CLLtnpqE18ECFQQFwwod1z8ALw

SUMMARY

It is unfortunate that, despite the long existence of evidence-based guidelines and NICE quality standards, asthma continues to extract a heavy toll in terms of continuing morbidity and an unacceptable number of avoidable deaths.

The diagnosis and management of childhood asthma can sometimes be challenging. But, like most things that are challenging, success, in terms of helping children achieve good asthma control and a normal life, can be hugely rewarding.

REFERENCES

1. British Thoracic Society, Scottish Intercollegiate Guidelines Network. British Guideline on the Management of Asthma: a national guideline, 2014 https://www.brit-thoracic.org.uk/guidelines-and-quality-standards/asthma-guideline/

2. Henderson J, Granell R, Heron J, et al. Associations of wheezing phenotypes in the first 6 years of life with atopy, lung function and airway responsiveness in mid-childhood. Thorax 2008;63:974-80

3. Bush A, Grigg J, Saglani S. Managing wheeze in preschool children. British Medical Journal 2014; 348: g15 http://www.bmj.com/content/348/bmj.g15

4. Robertson CF, Price D, Henry R et al. Short-course montelukast for intermittent asthma in children: a randomized controlled trial. American Journal of Respiratory and Critical Care Medicine 2007;175:323-9

5. Valovirta E, Boza ML, Robertson CF et al. Intermittent or daily montelukast versus placebo for episodic asthma in children. Annals of Allergy, Asthma and Immunology 2011; 106: 518-26

6. Bacharier LB, Phillips BR, Zeiger RS et al. Episodic use of an inhaled corticosteroid or leukotriene receptor antagonist in preschool children with moderate-to-severe intermittent wheezing. Journal of Allergy and Clinical Immunology 2008;122:1127-35

7. Oomen A, Lamber PC, Grigg J. Efficacy of a short course of parent-initiated oral prednisolone for viral wheeze in children aged 1-5 years. Lancet 2003;362:1433-8

8. Panickar J, Lakhanpaul M, Lambert PC et al. Oral prednisolone for preschool children with acute virus-induced wheezing. New England Journal of Medicine 2009;360:329-38

9. Andersen ZJ, Loft S, Ketzel M et al. Ambient air pollution triggers wheezing symptoms in infants. Thorax 2008; 63:710-6

10. Pool J, Petrova N, Russell RR. Exposing children to secondhand smoke. Thorax 2012;67:926