Bronchiolitis

See also resp symptoms in children for the general respiratory severity framework this pathway draws on.

Key points

1. Bronchiolitis is a clinical diagnosis — a viral lower respiratory tract infection, generally in children under 12 months.
2. No investigations should be routinely performed.
3. Management is supportive — feeding and oxygenation as required.
4. No medication should be routinely given (no bronchodilators, steroids, or antibiotics).

Background

Peak severity is usually day 2–3 of the illness, resolving over 7–10 days; the cough may persist for weeks.

Typical course: acute URTI symptoms, followed by respiratory distress and fever with one or more of: cough, tachypnoea, retractions, widespread crackles or wheeze.

Risk factors for more serious illness

Age <10 weeks; chronic lung disease; congenital heart disease; chronic neurological conditions; Aboriginal and/or Torres Strait Islander ethnicity; immunodeficiency. Infants with any of these risk factors can deteriorate rapidly — consider admission even with mild symptoms presenting early.

Severity grading

	Mild	Moderate	Severe
Behaviour	Normal	Some/intermittent irritability	Increasing irritability and/or lethargy, fatigue
Respiratory rate	Normal–mild tachypnoea	Increased	Markedly increased or decreased
Accessory muscle use	Nil–mild chest wall retraction	Moderate retraction, suprasternal retraction, nasal flaring	Marked retraction, suprasternal retraction, nasal flaring
Oxygen saturation	>92% (room air)	90–92% (room air)	<90% (room air), may not correct with O₂
Apnoea	None	May have brief apnoea	Increasingly frequent/prolonged apnoea
Feeding	Normal	May have difficulty/reduced feeding	Reluctant or unable to feed

Investigations

Not required in most children. CXR is not routinely indicated (may prompt unnecessary antibiotic treatment); blood tests (blood gas, FBC, blood cultures) and virological testing have no role in individual case management. Reserve investigation for genuine diagnostic uncertainty (e.g. a murmur with signs of congestive cardiac failure).

Management

Supportive: oxygenation, fluid intake, minimal handling.

• Mild — if the family has appropriate access to emergency services and GP follow-up, supportive care alone (hydration, secretion management) is enough; otherwise, or if risk factors are present, send to ED.
• Moderate — likely admission, possibly dischargeable after observation; discuss with a senior physician.
• Severe — admission and consider transfer to a children’s facility/ PICU; refer early.

Oxygen and respiratory support (2025 update — see below for what changed):

• Age ≥6 weeks, no comorbidity: give oxygen if saturations persist <90%.
• Age <6 weeks, or any comorbidity: give oxygen if saturations persist <92%.
• Start with low-flow (nasal prong) oxygen. High-flow nasal cannula (HFNC) is no longer first-line for moderate bronchiolitis — reserve it for infants with persistent hypoxaemia despite low-flow oxygen, or for severe disease (± CPAP).

Hydration/nutrition: small, frequent feeds; if feeding <50% over 12 hours, give NG hydration.

Observations: mild — at least two recorded measurements before discharge, or every 4 hours; moderate — 1–2 hourly (not continuous), discontinue SpO₂ monitoring once improving and oxygen-free for 2 hours; severe — hourly with continuous cardiorespiratory monitoring.

Escalation (severe): consider ICU review/transfer if severity doesn’t improve, desaturations persist, significant/recurrent apnoea occurs with desaturation, or risk factors are present.

Parental education: explain the expected course and when to return (worsening symptoms, inability to feed adequately). Provide the RCH parent information sheet.