Paediatrics

Bronchiolitis

An acute viral small-airway infection in babies and young children causing coryza, cough, tachypnoea, wheeze or crackles and feeding difficulty; treatment is supportive, with escalation driven by work of breathing, hydration, apnoea and oxygenation.

In a nutshell

Bronchiolitis is diagnosed clinically in a baby or young child with coryza followed by cough, tachypnoea or recession, and wheeze or crackles. Treatment is supportive: monitor work of breathing, feeding and oxygenation, give oxygen at the current age- and risk-specific thresholds, support fluids and escalate apnoea or impending respiratory failure.

Classic presentation

A baby under 1 year with 1 to 3 days of coryza followed by cough, tachypnoea, widespread wheeze or fine crackles and reduced feeding.

Key points

Symptoms commonly peak at days 3 to 5; cough may last up to around 3 weeks.
Apnoea may be the only obvious sign in a very young or premature infant.
Persistent oxygen saturation below 90% in children aged 6 weeks and over, or below 92% in babies under 6 weeks or children with underlying health conditions, prompts oxygen and hospital-level care; referral uses the separate clinical threshold of below 92% in air.
Do not use salbutamol, nebulised adrenaline, corticosteroids, hypertonic saline, montelukast, ipratropium or antibiotics for uncomplicated bronchiolitis.
Use suction only for apnoea or when secretions cause distress or feeding difficulty; do not routinely suction.
Give nasogastric or orogastric fluids if oral intake is inadequate; use IV isotonic fluid if enteral fluid is not tolerated or respiratory failure is impending.
Discharge requires clinical stability, adequate oral intake and the relevant oxygen saturation maintained in air for 4 hours including sleep.
Give carers clear red flags: worsening work of breathing, markedly reduced intake or no wet nappy for 12 hours, apnoea, cyanosis or exhaustion.

First-line investigation

Clinical assessment plus pulse oximetry; no routine blood tests or chest X-ray.

Management

Recognise severity and escalate red flags

Treat apnoea, central cyanosis, severe respiratory distress, exhaustion or a seriously unwell appearance as emergency features and arrange hospital care.^1,3

Assess oxygenation and hydration

Measure pulse oximetry, document work of breathing and assess feeding, wet nappies and dehydration; account for age, prematurity, comorbidity and carer circumstances.^1,5

Give supportive care

Give oxygen using the current age- and risk-specific thresholds, use selective suction for apnoea or secretion-related distress, and support hydration enterally where possible.^1,5
Do not use salbutamol, steroids, antibiotics, nebulised adrenaline, hypertonic saline, montelukast or ipratropium for uncomplicated bronchiolitis.¹

Escalate impending respiratory failure

Seek paediatric critical-care support for recurrent apnoea, exhaustion or failure to maintain oxygenation despite oxygen; consider CPAP and selective blood gas or chest radiography.¹

Discharge with safety-netting

Discharge only when clinically stable, adequately hydrated and maintaining the relevant saturation in air for 4 hours including sleep; provide written red flags and immediate-help instructions.^1,3

Exam traps

Wheeze in bronchiolitis is not an indication for salbutamol.
A falling respiratory rate with increasing fatigue or reduced effort can indicate exhaustion.
Oxygen thresholds differ for admission and referral, and the under-6-week or underlying-condition threshold remains 92%.
Do not use a chest X-ray to decide whether antibiotics are needed in uncomplicated bronchiolitis.
Do not discharge on saturation alone: clinical stability, feeding and a period including sleep also matter.

Illustrations

Obstructed bronchiole cross-sectionComparative diagram of a normal versus an inflamed infant bronchiole showing how mucosal oedema and debris narrow a small airway.PassFinals · original

Infant respiratory distress signsIllustration of intercostal and subcostal recession, nasal flaring and tracheal tug used to assess severity.PassFinals · original

Chest X-ray of hyperinflationChest radiograph showing hyperinflation and patchy atelectasis; imaging is not routinely required but is shown for teaching when intensive care or an alternative diagnosis is being considered.James Heilman, MD, Wikimedia Commons · CC-BY-SA-3.0

Key sources

This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.