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Bronchiolitis

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Overview

Bronchiolitis is an acute viral infection of the lower respiratory tract most commonly seen in < 2-year-olds. It is generally self-limiting and management is mainly supportive.

Respiratory syncytial virus (RSV) is the most common cause.

Epidemiology

  • Most common in infants <2 years with peaks at 3 and 6 months
  • Most common cause of serious lower respiratory tract infection in < 1-year-olds
  • Peak incidence is in the winter months 

Risk Factors

Factors associated with more severe disease include:

  • Prematurity
  • Bronchopulmonary dysplasia
  • Congenital heart disease
  • Impaired airway clearance (e.g. cystic fibrosis, primary ciliary dyskinesia)
  • Immunodeficiency
  • Maternal smoking or passive smoke exposure
  • Neuromuscular disorders

Presentation

Bronchiolitis is characterised by 1-3 days of preceding coryza (runny nose, nasal congestion, sneezing) with or without fever followed by:

  • Persistent cough
  • Either tachypnoea, chest recessions, or both
  • Wheeze, crackles, or both

Red flag features

  • Apnoea
  • Features of severe respiratory distress:
    • Grunting
    • Marked chest recession
    • Respiratory rate >70 /min
    • Head bobbing
    • Nasal flaring
    • Tracheal tugging
  • Central cyanosis
  • Oxygen saturations <92% when breathing air

Referral

Overview

Immediately refer to hospital by ambulance if any of the following features are present:

  • Apnoea – either if seen in clinic or reported by the parent
  • Infant looks seriously unwell to a healthcare professional
  • Features of severe respiratory distress:
    • Grunting
    • Marked chest recession
    • Respiratory rate >70 /min
  • Central cyanosis
  • Oxygen saturations <92% when breathing air

Consider a referral to hospital if any of the following apply:

  • Respiratory rate >60 /min
  • Difficulties with feeding or oral fluid intake (around 50-75% of the usual volume, taking into account risk factors and using clinical judgement)
  • Dehydration

Investigations

All patients

  • Pulse oximetry:
    • To screen for hypoxia
  • Viral throat swabs:
    • Can identify RSV

Other investigations

Other investigations such as chest X-rays and blood tests are not routinely performed unless there is diagnostic doubt or deterioration.

If pneumonia is suspected (discussed in differential diagnoses), perform a chest x-ray.

Differential Diagnoses

Pneumonia

A diagnosis of pneumonia should be considered if any of the following apply:

  • A high fever (>39°C)
  • Persistently focal crackles

Asthma or viral-induced wheeze

  • Persistent crackles may be present
  • Recurrent episodic wheeze may be present
  • Personal or family history of atopy may be present

Croup

  • Patients have inspiratory stridor and a barking cough
  • Symptoms are worse at night

Management

Overview

Treatment is supportive:

  • Humidified oxygen is given if their oxygen saturations are:
    • Persistently <90% if aged 6 weeks and older
    • Persistently <92% if under 6 weeks or children of any age with underlying health conditions
  • Upper airway suctioning may be considered if there is respiratory distress or feeding difficulty
  • Nasogastric feeding may be considered if oral intake is insufficient

Patient Advice

  • Carers should use paracetamol/ibuprofen for fevers if the child is distressed
  • Carers should check on the child regularly and seek help if any deterioration occurs such as:
    • Breathing rate increases or there is apnoea, cyanosis, or increased work of breathing (grunting, nasal flaring, head bobbing, marked chest recessions)
    • Fluid intake 50-75% of normal
    • Signs of dehydration – dry mouth or no wet nappy for 12 hours
    • Child becomes less responsive or difficult to rouse 

Prognosis

  • Bronchiolitis is generally self-limiting and lasts for 3-7 days
  • The cough may persist for up to 3 weeks

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