Following publication earlier this year of NICE guidance on the diagnosis and management of bronchiolitis, the authors consider the implications, treatment options and referral pathways in general practice


Dr Claire Evans, Specialist Registrar
Dr Michael Yanney, Consultant Paediatrician, Sherwood Forest Hospitals NHS Foundation Trust 

Bronchiolitis is a clinical diagnosis defined as “a seasonal viral illness characterised by fever, nasal discharge and a dry wheezy cough. On examination there are fine inspiratory crackles with or without high pitched expiratory wheeze.”1 There are variations in accepted definitions, and in North America the definition of bronchiolitis is broadened to include all children up to the age of two years who present with a wheezing illness associated with an upper respiratory tract infection (URTI). This definition includes children who in the UK would be considered to have “viral induced wheeze”, which has a different natural history and treatment options.2 Bronchiolitis is the commonest acute lower respiratory tract infection in infants. About one in three infants develop clinical bronchiolitis in the first year of life, the majority of whom will have a mild illness and can be safely managed by parents at home.

It can occur in children up to two years of age, but has a peak incidence between three and six months. Each year, about 2-3% of the birth cohort will be admitted to hospital during the bronchiolitic season.

In 2011/2012 there were over 30,000 hospital admissions for bronchiolitis in England and in 2009/2010 there were 72 recorded deaths in children within 90 days of hospital admission.3 The mortality risk in otherwise healthy children is low but increases substantially with pre-existing medical conditions.

Mortality in previously healthy infants is about 0.5% of children admitted to hospital and about 3.5% in infants with underlying pathologies including chronic lung disease and congenital heart disease.4,5 Other groups at high risk of severe illness are infants with neuromuscular disorders or immunodeficiency. NICE Bronchiolitis is a clinical diagnosis defined as “a seasonal viral illness characterised by fever, nasal discharge and a dry wheezy cough. On examination there are fine inspiratory crackles with or without high pitched expiratory wheeze.”1 There are variations in accepted definitions, and in North America the definition of bronchiolitis is broadened to include all children up to the age of two years who present with a wheezing illness associated with an upper respiratory tract infection (URTI). This definition includes children who in the UK would be considered to have “viral induced wheeze”, which has a different natural history and treatment options.2 Bronchiolitis is the commonest acute lower respiratory tract infection in infants. About one in three infants develop clinical bronchiolitis in the first year of life, the majority of whom will have a mild illness and can be safely managed by parents at home.

It can occur in children up to two years of age, but has a peak incidence between three and six months. Each year, about 2-3% of the birth cohort will be admitted to hospital during the bronchiolitic season.

In 2011/2012 there were over 30,000 hospital admissions for bronchiolitis in England and in 2009/2010 there were 72 recorded deaths in children within 90 days of hospital admission.3 The mortality risk in otherwise healthy children is low but increases substantially with pre-existing medical conditions.

Mortality in previously healthy infants is about 0.5% of children admitted to hospital and about 3.5% in infants with underlying pathologies including chronic lung disease and congenital heart disease.4,5 Other groups at high risk of severe illness are infants with neuromuscular disorders or immunodeficiency. NICE but there are a number of risk factors associated with an increased severity of illness, morbidity and mortality (Box 2). These should be taken into consideration when assessing a child for referral or admission, as should the stage of the illness at which they present. A child who presents on day one is likely to worsen, and this needs to be considered when deciding on referral and also included in the explanation and safety netting advice given to parents.

The differential diagnosis for bronchiolitis includes pneumonia and viral associated wheeze.

Less commonly, children with sepsis, congenital lung malformations or cardiac anomalies may present with symptoms that overlap with those of bronchiolitis.

NICE guidance – diagnosis

NICE suggests a set of features in the presentation of an infant that should lead to a diagnosis of bronchiolitis and also features that should suggest an alternative diagnosis.

Bronchiolitis occurs in children under two years of age and most commonly in the first year of life, peaking between three and six months

Diagnose bronchiolitis if a child has a coryzal prodrome lasting one–three days, followed by:

  • persistent cough and
  • either tachypnoea or chest recession (or both) and
  • either wheeze or crackles on chest auscultation (or both)

Symptoms usually peak between three–five days, and the cough resolves in 90% of infants within three weeks

The following symptoms are common in children with bronchiolitis:

  • fever (in around 30% of cases, usually < 39°C)
  • poor feeding (typically after three–five days of illness)

Infants (particularly those under six weeks of age) may present with apnoea without other clinical signs

Consider a diagnosis of pneumonia if the child has:

  • high fever (> 39°C) and/or
  • persistently focal crackles

Consider a diagnosis of viral-induced wheeze or early-onset asthma rather than bronchiolitis in older infants and young children if they have:

  • persistent wheeze without crackles or
  • recurrent episodic wheeze or
  • a personal or family history of atopy.

Take into account that viral-induced wheeze or early onset asthma are unusual in children under one year of age.

NICE guidance – assessment

Routine assessment of bronchiolitis should include the use of pulse oximetry. Assessment criteria for the severity of breathing difficulty in children, based on WHO guidance, suggest that an O2 saturation > 95% is associated with mild severity, 92-95% – moderate and <92% – severe.1 NICE guidance recommends that all children with persistent O2 saturation <92% in air should be admitted to hospital.3 It is also important to assess for features that may indicate the need for intensive care management – signs of exhaustion including listlessness and decreased respiratory effort, recurrent apnoea and failure to maintain adequate oxygen saturation despite O2 supplementation.3

NICE guidance – referrals

NICE guidance suggests a number of criteria that should prompt either immediate referral or consideration of referral to secondary care rather than home care with advice. These are summarised in Box 3.3 NICE guidance suggests taking into account the factors which may predispose to more severe bronchiolitis when considering the need for referral (see Box 2).3 They also suggest bearing in mind factors which may affect a carers ability to care for a child with bronchiolitis including:

  • Social circumstances
  • The skill and confidence of the carer in looking after a child with bronchiolitis at home 
  • Confidence in being able to spot red flag symptoms
  • Distance to healthcare in case of deterioration.

If deciding not to refer to secondary care they also provide guidance on safety netting advice to give to parents. This includes general advice points such as not smoking in the child’s home as this can exacerbate symptoms, how to get immediate help from an appropriate health care professional if red flag symptoms develop, follow up arrangements if necessary and red flag symptoms (see Box 4).3 Those with risk factors for severe disease may need consideration for earlier admission than those who have been previously healthy.

Treatment

Research studies over several decades into a range of treatments for bronchiolitis have been disappointing, with inconsistent findings or no evidence of benefit.

Supportive care with the use of oxygen to maintain adequate saturations and nasogastric feeding or intravenous fluids to maintain hydration remains the mainstay of treatment.13,14 Where the clinical condition deteriorates and increasing oxygen therapy is failing to maintain oxygen saturations, respiratory effort decreases through exhaustion or there are recurrent apnoeas, non-invasive or invasive ventilation may be required to support the infant through the illness.

Corticosteroids

Although the pathophysiology of bronchiolitis includes inflammation, the use of corticosteroids has been shown to be of no benefit in reducing length of stay, rates of admission or clinical scores.15 This result has been replicated in randomised controlled trials and systematic reviews.2

Beta 2 agonists

The use of bronchodilators have mixed evidence. Most studies conclude that there is no benefit to their use with some suggesting there may be short-term improvement in clinical scores. The results may in part be confounded by studies using the North American definition of bronchiolitis which includes those with viral induced wheeze.1,16 Overall, bronchodilators are not useful in bronchiolitis.

Antibiotics

There is no role for the routine use of antibiotics in bronchiolitis.17 They should only be used in situations where there is evidence of secondary bacterial infection. As included in the NICE guidance, chest x-ray should not be a routine investigation in bronchiolitis, as changes due to mucous plugging can mimic consolidation and pneumonia. Therefore, chest x-ray changes in isolation should not be used to decide on antibiotic treatment.3

Hypertonic saline

There has been some controversy in recent years as to whether the use of hypertonic saline may be of benefit in bronchiolitis. A Cochrane review in 2013 concluded that nebulised hypertonic saline 3% could lead to a reduction of 1.2 days in mean length of stay in hospitalised patients with moderate acute bronchiolitis and improve clinical severity scores for both in and outpatients.18 However, a multicentre controlled trial (SABRE) by Everard et al randomised 317 infants admitted with a diagnosis of acute bronchiolitis and requiring oxygen therapy, to treatment with either normal supportive care or nebulised 3% hypertonic saline. The authors found no difference in length of stay or incidence of adverse outcome.19 Hypertonic saline is therefore not recommended by NICE for the treatment of acute bronchiolitis.3 The evolving evidence for the use of hypertonic saline for bronchiolitis highlights the need for robustly designed studies to inform management decisions and to avoid ineffective treatments becoming accepted into routine practice.

Antivirals

There have been some studies investigating the role of antivirals such as ribavirin in bronchiolitis, but these have been small and inadequately powered.2

A Cochrane review concluded that there was some evidence that its use may reduce duration of mechanical ventilation and hospital stay, but did not reduce rates of deterioration or mortality.20 Ribavirin is only currently recommended in immunocompromised patients.2

Others

Other treatments studied include leukotriene receptor antagonist and nebulised adrenaline.21-23 For both therapies there is a lack of evidence for their use in bronchiolitis.

Vaccination

At present there is no vaccine available for RSV, although phase 2 trials of two possible vaccines are underway.24 Initial trials in the 1960s of a vaccine containing inactive RSV led to a good IgG response, but actually increased rather than decreased the severity of subsequent infections.25,26 Barriers to effective vaccination for RSV also include the need to cover multiple viral strains and regular booster vaccinations as infection does not confer immunity.24

Passive Immunisation

Palivizumab is a humanised monoclonal antibody which can confer passive immunisation to RSV. The Impact-RSV trial showed a 55% reduction in RSV related hospitalisation, less days in hospital and lower incidence of intensive care admission when administered monthly over the RSV season.27 

The Joint Committee on Vaccination and Immunisation (JCVI) recommends the use of palivizumab in the following groups:10

  • High risk due to brochopulmonary dysplasia (BPD) – also known as chronic lung disease
  • Pre-term infants who have moderate or severe BPD. Moderate or severe BPD is defined as ‘pre-term infants with compatible x-ray changes who continue to receive supplemental oxygen or respiratory support at 36 weeks postmenstrual age’10
  • Infants with respiratory diseases who are not necessarily pre-term but remain in oxygen at the start of the RSV season. These infants may include those with conditions such as: 
    • pulmonary hypoplasia due to congenital diaphragmatic hernia, 
    • other congenital lung abnormalities (sometimes also involving congenital heart disease or lung malformation), 
    • interstitial lung disease
  • Those receiving long term ventilation at the onset of the season
  • High risk due to congenital heart disease (CHD)
  • Preterm infants with haemodynamically significant, acyanotic CHD at specified chronological and gestational ages at birth
  • Cyanotic or acyanotic CHD plus significant co-morbidities, particularly if multiple organ systems are involved 
  • High risk due to severe combined immunodeficiency (SCID) – children under 2 years of age.

Summary

Bronchiolitis is a viral illness of the respiratory tract and a common cause of hospitalisation and morbidity in the infant population. NICE published guidance in 2015 on the diagnosis and management of bronchiolitis.3 There are at risk populations for whom a lower threshold for referral and hospital admission should be used. Poor clinical condition including respiratory distress, inadequate hydration and signs of exhaustion are all features which should prompt referral to secondary care.

Safety netting advice is vital to all those not referred to, or discharged from hospital. There are no active treatment options and therapies are therefore supportive only. At risk groups should be administered palivizumab as prophylaxis.


Summary of key points

1 Bronchiolitis is a clinical diagnosis characterised by a coryzal prodrome, tachypnoea, bilateral crackles +/- wheeze
2 At risk groups include preterm or low birth weight infants, children with chronic lung disease, neuromuscular disorders, congenital heart disease or immunodeficiency
3 Criteria for hospital admission are: tachypnoea (> 60 breaths/min), O2 saturations <92% in air or feeding at 50–75 % of usual amounts
4 Red flags that require urgent referral include apnoea, severe respiratory distress, grunting, cyanosis or exhaustion
5 Treatment for admitted patients involves supportive care with oxygen therapy and nasogastric feeds or intravenous fluids 
6 There is no role for the routine use of antibiotics and there is insufficient evidence to support the use of any other pharmacological therapies
7 Passive immunisation with Palivizumab should be given to at risk groups who meet the JCVI criteria


References

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