August 2007: Diagnosing respiratory problems in young children
Preschool children with respiratory problems will typically present with abnormal features that the parents have observed (signs) rather than the subjective feelings of distress an older child or adult might present with (symptoms). Most often the parents will report:
• Noisy breathing (the words used to describe noisy breathing by parents are notoriously imprecise. This is particularly true of ‘wheezing', which may need to be described or even demonstrated to parents).
– A rattly expiratory noise often heard in young children, which may be described by parents as ‘rattles' (South of England), ‘ruttles' (North of England) or ‘hurstles' (Ireland and Scotland)
– Grunting. This may be part of normal vocalisation if it is infrequent in an otherwise well infant. Conversely, in an infant with respiratory distress, persistent grunting at the end of expiration suggests severe illness
• Rapid or laboured breathing
• Fatigue or poor exercise tolerance
• Sleep disturbance
• Colour change
• Foreign body ingestion. This may not be mentioned by the parents but should always be asked about in a previously well child with recurrent infections or wheeze.
Most respiratory illnesses in children are short-lived and self-limiting, and are secondary to acute respiratory tract infections (RTIs). Most parents recognise this and will present when the symptoms are more severe or last longer than they expect.
Upper RTIs are usually viral and produce less severe symptoms. They are characterised by nasal congestion, coryza, sore throat, cervical lymphadenopathy, cough, pyrexia and occasionally conjunctivitis or acute otitis media.
Lower RTIs are often bacterial and may require more aggressive treatment. They are characterised by tachypnoea, increased work of breathing, pyrexia, cough, lethargy and poor feeding.
Symptoms and signs may help to distinguish between lower and upper RTIs, but signs in younger children are less reliable than in older children and adults.
Typical infections involving the lower respiratory tract include croup (acute laryngotracheobronchitis), bronchiolitis and pneumonia (which may be viral pneumonia, pneumonitis or bacterial pneumonia).
Tachypnoea is the most reliable sign of pneumonia in a young child. Wheezing, particularly in young children, is strongly suggestive of a viral infection. A wet cough is suggestive of a suppurative process, but many children with pneumonia will have a dry cough. Moreover, the distinction between upper and lower RTIs may be largely arbitrary, as many infections involve both the upper and lower respiratory tract.
How and when should asthma be diagnosed in young children?
The term ‘asthma' usually refers to typical atopic asthma, which is characterised by allergic sensitisation and recurrent wheezing. Asthma is a very common condition in childhood and its incidence in the developed world has increased significantly over the past 30 years. This rise appears to have reached a plateau, and the incidence may now be falling.1
However, asthma remains a difficult condition to define and therefore to diagnose, particularly in younger children because of the high prevalence of wheeze secondary to acute RTIs in children who do not share the characteristic features of atopic asthma seen in older children and adults. This has led many doctors to avoid diagnosing asthma in early childhood.
Wheezing seen in early childhood has been variously labelled as viral wheezing, viral-associated wheezing or wheezy bronchitis. It usually has a good prognosis and children will often outgrow their symptoms.2
Intermittent, viral-associated wheeze should not be treated with regular inhaled corticosteroids.
There is a natural reluctance to label children with wheeze who may outgrow their symptoms as having asthma. However, it is reasonable to consider a diagnosis of asthma even in young children if there is evidence of allergic sensitisation and recurrent wheezing (particularly if wheezing has occurred without an obvious viral infection).
The risk of a young child developing atopic asthma increases with a strong family history of atopic disease (asthma, eczema, hayfever or anaphylaxis), a personal history of other atopic disease or wheezing in the absence of a viral infection.
How does diagnosis and management differ with the age of the child?
The primary question in the diagnosis of a young child with wheeze is whether the child has atopic asthma or viral wheezing. As discussed above, most young children with wheeze will have viral wheezing.
The treatment of viral wheezing is largely symptomatic, with the use of inhaled ß2-agonists via a metered-dose inhaler and spacer. More recently the use of leukotriene receptor antagonists, such as montelukast, at the first sign of a viral RTI has been advocated as reducing the incidence and severity of viral wheeze.3
Inhaled corticosteroids, the mainstay of treatment in atopic asthma, have not been shown to be of benefit in viral wheeze. However, they continue to be prescribed, particularly where there is diagnostic uncertainty between viral wheeze and atopic asthma.
The BTS and SIGN published a guideline on the management of asthma in 2003. This has been updated several times in electronic format with the most recent update being in July 2007.4 The guideline continues to provide excellent and comprehensive guidance on the management of asthma in adults and children for both GPs and paediatricians. One of the most useful functions of the guideline is to highlight the limitations of current evidence for the treatment of wheezy children.
The recommendations are divided into the management of children aged 5-12 years and children aged less than five years. In some recommendations, particularly in the treatment of acute asthma, treatment is further subdivided into children aged 2-5 years and children aged less than two years.
The different recommendations reflect both the higher prevalence of viral wheezing in younger children and the better evidence base for the management of older children and adults.5
Since 2003, there have been several large studies looking at the usefulness of montelukast in young children with wheeze. As discussed above, montelukast does appear to be helpful in viral wheeze. It also appears to be useful in children with asthma and can be considered in young children with atopic asthma who have problems with inhaled treatment. However, in head-to-head trials comparing montelukast with inhaled corticosteroids in children with atopic asthma, inhaled corticosteroids continue to produce slightly better control of symptoms.
How should symptom control be evaluated?
Symptom control is a balance between appropriate prescribing, appropriate use of medicines (including compliance and inhaler technique) and the underlying disease process (severity of disease and exacerbating factors). Loss of control may be precipitated by changes in any of these areas.
Early signs of loss of control can be subtle. Children may cough or clear their throat rather than wheeze. Wheeze may only be precipitated in particular situations (especially with exercise) or at particular times (especially at night).
The frequency of use of reliever medication is a useful guide to symptom control, but assumes that the difference between reliever and preventer medications is understood. In the past reliever medications
(ß-agonists) were often prescribed regularly in the belief that this would improve deposition of a subsequently inhaled corticosteroid. Most respiratory paediatricians would no longer recommend this as it can cause confusion and problems with compliance. There are also potential risks associated with regular ß-agonist use, as this may mask ongoing airway inflammation.
Lung function tests are very difficult to perform in young children, even in specialist centres, and so lung function measurements (for example peak flow diaries) cannot be used to monitor symptom control in children less than five years of age.
Acute exacerbations are an obvious sign of loss of control. These may be unavoidable in severe disease, even with careful monitoring by a specialist. However, they should always prompt a review of treatment, looking at the areas affecting symptom control outlined above.
Which children will improve as they get older?
It is impossible to predict accurately which children will improve or to guarantee parents that a child will grow out of their symptoms – we can only offer guidance as to whether it is likely or unlikely.
Children with viral wheeze are most likely to grow out of their symptoms. However, occasionally the diagnosis of viral wheeze will be seen to be wrong only in retrospect, as in cases when a child is older, still wheezing and has developed hayfever.
Children with atopic asthma may improve as they get older. However, children with severe symptoms are less likely to improve. Moreover, the remission of symptoms in atopic asthma often seen in adolescence may not mean that the disease has gone completely; it may recur in later life. Girls are less likely to grow out of symptoms than boys.6
Some children may have conditions that predispose them to severe wheeze in early childhood but which improve with age. For example, children who suffer severe bronchiolitis are likely to continue to wheeze intermittently during childhood, but this may resolve.7
What are the red flags for urgent review or admission?
Most doctors will recognise the seriously ill child. However, a seriously ill child who is deceptively quiet and ‘well behaved' because they are too breathless to talk or play, or are concentrating on maintaining their airway, can be misleading. On the other hand, hypoxic children may appear agitated or confused.
Stridor is evidence of upper airway obstruction, which can be rapidly fatal. Doctors should be particularly wary of any child who has stridor at rest or while they are sleeping, especially if the stridor is associated with drooling or dysphagia. The most likely causes are:
• Croup (acute laryngotracheobronchitis)
• Foreign body ingestion
• Bacterial tracheitis
• Acute epiglottitis (now less common because of immunisation against Haemophilus influenzae type b).
It is important not to examine the oropharynx in a child with acute stridor, except in carefully controlled circumstances.
Young infants will occasionally present with stridor because of congenital laryngomalacia. This is usually not acute and is often present from a few weeks after birth. This may not need to be reviewed urgently, provided that the child is comfortable at rest and feeding well, but will often need referral to a paediatrician.
Other potentially life-threatening presentations include:
• Acute asthma associated with silent chest
• Poor respiratory effort
Young children with tachypnoea and pyrexia are likely to have either pneumonia or bronchiolitis.
Infants with bronchiolitis require admission to hospital if they cannot feed (because of tachypnoea or exhaustion), have had episodes of apnoea or if they appear cyanosed or hypoxic.8
Children with community-acquired pneumonia require admission if they appear septic, hypoxic, or cannot tolerate oral fluids (in which case they are unlikely to tolerate oral antibiotics).9 Admission may also be required if family or home circumstances suggest care or compliance may be poor.
Other situations that should prompt urgent referral for more chronic conditions include:
• Any child with a persistent wet or loose cough (suggesting suppurative lung disease)
• Digital clubbing (which is often not sought in children)
• Symptoms not responsive to the usual medications (such as asthma not responding to moderate doses of inhaled corticosteroids).
• Weight loss or growth faltering (failure to thrive). This should be taken very seriously and usually requires referral to a paediatrician.
What is the evidence for the use of antibiotics in chest infections and exacerbations of asthma or wheeze?
In children aged less than five years, lower RTIs with wheeze are usually viral and antibiotics are seldom helpful. The same is true of infants with a typical bronchiolitis presentation.
However, in children with signs of pneumonia (tachypnoea, pyrexia and cough), antibiotics are the treatment of choice (even though some cases of pneumonia may be viral).
There is no evidence supporting the routine use of antibiotics in asthma.10 However, it should be remembered that children with asthma can get bacterial lower RTIs, just as other children can. Moreover, severe asthma exacerbations requiring hospital admission can be complicated by atelectasis with fever, or even nosocomial infections, for which antibiotics are often prescribed.
There is also evidence that a subset of children with a persistent wet cough may be suffering from ‘persistent bacterial bronchitis' and may benefit from antibiotic treatment. These children may sometimes have been misdiagnosed as suffering from asthma.11Diagnosing respiratory problems in young children Diagnosing respiratory problems in young children Useful information
The BTS/SIGN guideline on the management of asthma and the SIGN guideline on bronchiolitis in children can be downloaded free of charge from the SIGN website.
Dr Gary Doherty
BSc MB PhD
specialist registrar in paediatric respiratory medicine
Professor Andrew Bush
MD FRCP FRCPCH
Professor of Paediatric Respirology, Royal Brompton Hospital, London