Paeds · respiratory-sleep-and-airway
Bronchiolitis and viral lower respiratory tract infection
Also known as Acute viral bronchiolitis · RSV bronchiolitis · Viral lower respiratory tract infection · Infant viral wheeze · LRTI in infancy
Fellowship guide to bronchiolitis and viral lower respiratory tract infection: the RSV-driven small-airway obstruction of infancy that gives cough, tachypnoea, wheeze and crackles and difficulty feeding; grading severity by work of breathing, oxygenation and feeding; the differential from viral-induced wheeze, pneumonia, cardiac failure and foreign body; supportive care with feeding, targeted oxygen and high-flow or CPAP rescue while resisting bronchodilators, steroids and antibiotics; nirsevimab and palivizumab prevention; and the ANZ, UK and North American guideline differences.
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Target exams
Red flags
- Apnoea, especially in an infant under about eight weeks or born prematurely — it can be the first sign of bronchiolitis before the chest signs appear, and it mandates observation and escalation
- Oxygen saturation persistently below 90 percent on air, grunting, or severe recession — this infant needs oxygen, admission and close reassessment, not discharge
- Feeding less than about half of normal intake with reduced wet nappies — dehydration is a leading reason for admission and needs nasogastric or intravenous fluid support
- A tiring infant whose fast breathing slows while colour and conscious level worsen — impending respiratory failure, not improvement; escalate to high-flow, CPAP or intensive care
- Sudden focal signs, a heart murmur with hepatomegaly, high fever with focal crackles, or paroxysmal cough with a whoop — think foreign body, cardiac failure, pneumonia or pertussis rather than simple bronchiolitis
Life stages
Care settings
Clinical exam formats
Board mappings
- General and Community Paediatrics
- Acute respiratory illness
- Lower respiratory tract infection in infancy
- Current 2026 PREP curriculum — Learning goal 5: Clinical assessment – essential general paediatrics
- Renewed curriculum for first-year trainees from 2027 — Learning goal 6: Acute and critical care
- Paediatric respiratory and acute care competencies
- Clinical Applications
- Acute paediatrics and the lower airway
- Long Cases
- Short Cases
- Acute assessment scenarios
- 4. Professional skills and knowledge: Patient management
- 6. Acute and emergency care
- General Paediatrics: Recognises and manages acute respiratory illness in infants
- Foundation of Practice (FOP)
- Applied Knowledge in Practice (AKP)
- Acute respiratory illness; bronchiolitis
- Clinical
- History and management planning
- Acute respiratory assessment in infancy
- General Pediatrics Content Outline — Domain 2: Emergency Medicine
- General Pediatrics Content Outline — Domain 17: Respiratory System
- General Pediatrics EPA: Assess and manage the acutely ill child
- Patient Care 1: History and Physical Examination
- Patient Care 4: Clinical Reasoning
- Patient Care 5: Emergency and acute care
- Medical Knowledge 1: Clinical Knowledge
- Systems-Based Practice: high-value care and resource stewardship
- Medical Expert
- Communicator
- Health Advocate
- Scholar
- Pediatrics: Core EPA — Assess and manage the acutely ill infant with respiratory distress
Overview & Definition
Picture the six-week-old brought in on a winter afternoon: two days of a snuffly nose and a wet cough, and now she is breathing fast, her ribs draw in with every breath, there is a fine crackle and a soft wheeze across both lungs, and she has taken only half her feeds since morning. That scene — a young infant with a viral cold that has moved into the chest, breathing hard and feeding poorly — is bronchiolitis, and recognising it lets you settle into calm supportive care rather than a scramble of unhelpful drugs. [1] [2]
Bronchiolitis is an acute viral infection of the bronchioles, the smallest conducting airways, and the name tells you exactly where the trouble sits. The virus inflames the lining of these tiny airways, and the resulting debris, swelling and mucus obstruct airflow at a level where a young infant has very little reserve, which is why a common cold becomes a breathing and feeding problem. [2] [3]
Why this matters at fellowship level is that bronchiolitis is the commonest reason for infants to be admitted to hospital in the first year of life, it is overwhelmingly self-limiting, and it is the classic example of a disease where doing less is doing better. The skill being examined is disciplined supportive care, accurate severity assessment, and the confidence to withhold treatments that feel active but do not help. [1] [3]
References11ShowHide
- [1]Ralston SL, Lieberthal AS, Meissner HC, et al. Clinical practice guideline: the diagnosis, management, and prevention of bronchiolitis. Pediatrics, 2014.PMID 25349312
- [2]Meissner HC. Viral Bronchiolitis in Children. N Engl J Med, 2016.PMID 26735994
- [3]Florin TA, Plint AC, Zorc JJ. Viral bronchiolitis. Lancet, 2017.PMID 27549684
- [4]Fernandes RM, Bialy LM, Vandermeer B, et al. Glucocorticoids for acute viral bronchiolitis in infants and young children. Cochrane Database Syst Rev, 2013.PMID 23733383
- [5]Gadomski AM, Scribani MB. Bronchodilators for bronchiolitis. Cochrane Database Syst Rev, 2014.PMID 24937099
- [6]Zhang L, Mendoza-Sassi RA, Wainwright C, Klassen TP. Nebulised hypertonic saline solution for acute bronchiolitis in infants. Cochrane Database Syst Rev, 2017.PMID 29265171
- [7]Franklin D, Babl FE, Schlapbach LJ, et al. A Randomized Trial of High-Flow Oxygen Therapy in Infants with Bronchiolitis. N Engl J Med, 2018.PMID 29562151
- [8]Cunningham S, Rodriguez A, Adams T, et al. Oxygen saturation targets in infants with bronchiolitis (BIDS): a double-blind, randomised, equivalence trial. Lancet, 2015.PMID 26382998
- [9]The IMpact-RSV Study Group. Palivizumab, a humanized respiratory syncytial virus monoclonal antibody, reduces hospitalization from respiratory syncytial virus infection in high-risk infants. Pediatrics, 1998.PMID 9738173
- [10]Hammitt LL, Dagan R, Yuan Y, et al. Nirsevimab for Prevention of RSV in Healthy Late-Preterm and Term Infants. N Engl J Med, 2022.PMID 35235726
- [11]Skjerven HO, Hunderi JO, Brügmann-Pieper SK, et al. Racemic adrenaline and inhalation strategies in acute bronchiolitis. N Engl J Med, 2013.PMID 23758233