Acute Bronchiolitis - Paediatric

Quick Answer

One-liner: Acute viral bronchiolitis is the most common lower respiratory tract infection in infants, characterised by wheeze, crackles, and respiratory distress, managed primarily with supportive care including oxygen and fluids.

Bronchiolitis is an acute viral infection of the lower respiratory tract, primarily affecting infants aged 2-12 months. RSV is the responsible pathogen in 70-80% of cases. The hallmark is inflammation of the small airways (bronchioles) causing mucous plugging, air trapping, and wheeze. Management is predominantly supportive: maintain hydration, provide oxygen if hypoxaemic (SpO2 less than 90%), and monitor for complications. Hospital admission is required for infants with oxygen desaturation, feeding difficulties, apnoea, or significant respiratory distress. Routine bronchodilators, steroids, and antibiotics are not recommended for uncomplicated cases.

---

ACEM Exam Focus

Primary Exam Relevance

Anatomy:

• Small airway diameter in infants (3-5 mm at birth, 10 mm by 2 years)
• Increased airway resistance (Poiseuille's law: resistance ∝ 1/r⁴)
• Predominant cartilage deficiency in bronchioles leading to collapse
• Diaphragmatic breathing pattern (horizontal ribs, limited chest wall compliance)

Physiology:

• Oxygen-haemoglobin dissociation curve shifts in infants (left-shifted, high affinity for O₂)
• Ventilation-perfusion matching principles
• Respiratory drive regulation (central chemoreceptors respond to PaCO₂ less than PaO₂)
• Apnoea mechanisms in infants (predominantly central)

Pharmacology:

• Bronchodilator mechanisms (β₂-agonists, anticholinergics) and lack of efficacy in bronchiolitis
• Corticosteroid mechanisms and evidence for minimal benefit
• Nebulised adrenaline rationale (α-mediated vasoconstriction, mild β-agonist effect)

Fellowship Exam Relevance

Written:

• Differentiation from viral-induced wheeze and asthma (key diagnostic dilemma)
• Admission criteria and disposition decisions
• Red flag identification (apnoea, hypoxaemia, feeding failure)
• Management of severe bronchiolitis requiring respiratory support

OSCE:

• Assessment of respiratory distress in infants (respiratory rate, work of breathing, auscultation)
• Communication with anxious parents about supportive management and natural history
• Breaking bad news (rare death scenarios)
• Clinical examination focused on wheeze, crackles, retractions

Key domains tested: Medical Expert, Communicator, Health Advocate (prevention strategies)

---

Key Points

---

Epidemiology

Australian/NZ Specific

• Indigenous infants: Hospitalisation rates 3-5 times higher than non-Indigenous infants [10]
• Remote/remote communities: Higher RSV infection rates due to overcrowding and limited healthcare access
• Prematurity impact: Former preterm infants (below 32 weeks) have 4-6 times higher hospitalisation risk for bronchiolitis [11]
• Palivizumab eligibility: Available through National Immunisation Program for high-risk infants (prematurity below 29 weeks, chronic lung disease, congenital heart disease) [12]

Indigenous Health Disparities

• Aboriginal and Torres Strait Islander infants have 3-5 times higher hospitalisation rates for bronchiolitis
• Māori infants in New Zealand have 2-3 times higher admission rates compared to non-Māori
• Contributing factors: lower birth weights, higher prematurity rates, overcrowded housing, socioeconomic disadvantage, delayed presentation to healthcare
• Need for culturally safe communication and family involvement in care decisions

---

Pathophysiology

Mechanism

Bronchiolitis is caused by direct viral infection of bronchiolar epithelial cells, leading to:

1. Necrosis of epithelial cells - especially ciliated cells, impairing mucociliary clearance
2. Peribronchiolar inflammation and oedema - reduces airway lumen diameter
3. Increased mucus production - viscous secretions further obstruct small airways
4. Air trapping and hyperinflation - due to ball-valve mechanism (inspiration easier than expiration)
5. Atelectasis - distal to obstructed airways leading to ventilation-perfusion mismatch

The combination of small airway diameter in infants (3-5 mm at birth) and the pathophysiological changes above creates significant resistance to airflow (Poiseuille's law: resistance ∝ 1/r⁴). Even modest reductions in airway diameter cause substantial increases in work of breathing.

Viral Pathogens

Why It Matters Clinically

• Airway obstruction → Increased work of breathing, respiratory distress, fatigue, respiratory failure
• Hypoxaemia from V/Q mismatch → Central cyanosis, lethargy, feeding difficulties
• Apnoea due to immature respiratory control and hypoxaemia → Life-threatening in young infants
• Dehydration from increased metabolic demand and feeding difficulties → Electrolyte abnormalities, hypovolaemia

---

Clinical Approach

Recognition

Bronchiolitis should be considered in any infant younger than 12 months presenting with:

• Viral prodrome (rhinorrhoea, low-grade fever, cough for 2-4 days)
• Progressive respiratory distress
• Wheeze (often polyphonic, expiratory)
• Fine inspiratory crackles (often bilateral)
• Hyperinflated chest (barrel-shaped)

Initial Assessment

Primary Survey

• Airway: Patent, observe for inspiratory stridor (suggests croup), drooling (epiglottitis - rare due to Hib vaccine)
• Breathing:
  • Respiratory rate (tachypnoea defined as greater than 60/min for infants 2-12 months)
  • Oxygen saturation (target ≥92%, intervention for below 90%)
  • Work of breathing (retractions, nasal flaring, grunting)
  • Auscultation (wheeze, crackles, air entry)
• Circulation: Capillary refill time, heart rate (tachycardia common with fever and respiratory distress), skin colour (pallor, cyanosis)
• Disability: AVPU scale, irritability, lethargy, seizures
• Exposure: Temperature, signs of dehydration (dry mucous membranes, sunken fontanelle)

History

Key Questions

Red Flag Symptoms

Examination

General Inspection

• Respiratory distress (tachypnoea, retractions, nasal flaring, grunting)
• Alertness, irritability, or lethargy
• Colour (pale, pink, cyanosed)
• Hydration status (sunken eyes, dry mucous membranes, fontanelle)

Specific Findings

---

Investigations

Immediate (Resus Bay)

Standard ED Workup

Advanced/Specialist

Point-of-Care Ultrasound

POCUS has limited role in bronchiolitis management:

• Lung ultrasound: May show B-lines (alveolar interstitial syndrome) and subpleural consolidations, but findings are non-specific
• Not routinely recommended - clinical assessment and pulse oximetry are sufficient for most cases
• May be useful in differentiating from pneumonia when clinical uncertainty exists [20]

---

Management

Immediate Management (First 10 minutes)

1. Assess ABCDE and assign clinical severity (mild, moderate, severe)
2. Apply pulse oximetry - maintain SpO2 ≥92% (90-94% acceptable range)
3. Position upright (30-45 degrees) - improves respiratory mechanics
4. Maintain normothermia - manage fever with paracetamol if greater than 38.5°C
5. Monitor respiratory rate, work of breathing, and feeding status
6. Identify red flags requiring admission (apnoea, SpO2 below 90%, feeding failure)
7. Obtain focused history: age, duration, previous wheezing, comorbidities

Resuscitation (if Severe Disease)

Airway

• Maintain patent airway - head in neutral position, suction secretions if needed
• Avoid deep suctioning - can induce bradycardia and apnoea in infants
• Humidified oxygen - use high-flow nasal cannula if required (see below)

Breathing

Oxygen Therapy:

Key Point: SpO2 90-94% is acceptable; aggressive oxygen therapy to achieve greater than 94% is unnecessary and may prolong hospital stay [21]

High-Flow Nasal Cannula (HFNC):

• Indicated for infants with moderate to severe respiratory distress or persistent hypoxaemia despite conventional oxygen
• Reduces work of breathing by providing positive airway pressure, washes out anatomical dead space, and improves humidification
• Evidence shows reduced need for intubation and ICU admission [22]
• Dose: Start at 1-2 L/kg/min, titrate to response (max 15-20 L/min in infants)
• Maximal effect typically seen at 6-8 L/kg/min in children

Circulation

• IV or nasogastric fluids for infants unable to maintain adequate oral intake (below 50% normal)
• Maintenance fluids: 100 mL/kg/day for first 10 kg
• Correct dehydration if present (10 mL/kg bolus if clinically dehydrated)

Medications

Routine Medications (NOT Recommended)

Medications for Specific Indications

Paediatric Dosing

Ongoing Management

Monitoring:

• Continuous or intermittent pulse oximetry for hospitalised infants
• Vital signs every 2-4 hours initially (RR, HR, SpO2, temperature)
• Feeding assessment (volume, frequency, feeding quality)
• Work of breathing reassessment
• Apnoea monitoring for infants below 3 months or premature infants

Hydration:

• Encourage oral fluids if able to maintain greater than 50% normal intake
• Nasogastric tube feeds for infants with moderate dehydration or poor feeding
• IV fluids for severe dehydration or if NG tube not tolerated
• Target: 100 mL/kg/day for maintenance

Discharge Readiness:

• Respiratory distress improving (stable or decreasing RR)
• SpO2 ≥92% on room air for greater than 12 hours
• Feeding adequately (greater than 75% normal intake)
• No apnoea for 24 hours
• Parents confident with home management
• Clear discharge instructions with red flag education

Definitive Care

Most infants with bronchiolitis are managed in:

• Home: Mild disease, adequate feeding, SpO2 ≥92% on room air, no red flags
• General ward: Moderate disease, requiring oxygen, nasogastric feeds, or close monitoring
• Paediatric ICU: Severe disease requiring non-invasive ventilation, intubation, or with high-risk comorbidities

ICU/HDU Admission Criteria:

• Persistent hypoxaemia (SpO2 below 90%) despite HFNC at maximum flow
• Rising PaCO2 (greater than 50 mmHg) on capillary blood gas
• Recurrent apnoea requiring stimulation or intervention
• Severe respiratory distress with exhaustion (fatigue, decreased respiratory effort)
• Need for non-invasive ventilation (CPAP or BiPAP)

---

Disposition

Admission Criteria

• Hypoxaemia: SpO2 below 90% on room air (persistent)
• Respiratory distress: RR greater than 70/min, severe retractions, grunting, fatigue
• Feeding difficulty: Less than 50% normal intake over 24 hours
• Apnoea: Any apnoea episode at home or observed
• Age below 6 weeks: Respiratory distress in very young infants
• High-risk comorbidities: Prematurity (below 32 weeks), chronic lung disease, congenital heart disease, immunosuppression
• Dehydration: Clinical signs or significant fluid losses

ICU/HDU Criteria

• Respiratory failure: Rising PaCO2 (greater than 50 mmHg), persistent hypoxaemia despite HFNC
• Apnoea: Recurrent or prolonged apnoea requiring intervention
• Non-invasive ventilation: Need for CPAP or BiPAP
• High-risk comorbidities: Infants with significant cardiopulmonary disease

Discharge Criteria

Safe for discharge when ALL met:

1. Respiratory status: SpO2 ≥92% on room air for greater than 12 hours
2. Feeding: Adequate oral intake (greater than 75% normal), able to maintain hydration
3. Work of breathing: Mild or absent (no significant retractions, RR below 60/min)
4. No apnoea: No apnoea episodes for 24 hours
5. Parental confidence: Parents understand red flags and home management
6. Follow-up: Arranged with GP or appropriate paediatric service

Follow-up

• GP review: Within 48-72 hours of discharge
• Safety-netting: Immediate return if any red flag develops (apnoea, cyanosis, feeding failure, increased work of breathing)
• Education: Parents educated on:
  • Normal course of illness (peak symptoms 3-5 days, recovery 7-10 days)
  • Warning signs requiring medical review
  • Hydration strategies (small, frequent feeds)
  • Fever management
  • Smoke-free environment (avoid second-hand smoke exposure)
  • Hand hygiene to prevent spread

---

Special Populations

Premature Infants

Former preterm infants (below 32 weeks gestation) have:

• 4-6 times higher risk of hospitalisation for bronchiolitis
• Increased risk of severe disease and ICU admission
• Higher risk of apnoea due to immature respiratory control
• May qualify for palivizumab prophylaxis (monthly RSV monoclonal antibody during RSV season) [27]

Congenital Heart Disease

Infants with congenital heart disease:

• Increased risk of severe bronchiolitis due to fixed pulmonary blood flow
• Hypoxaemia may precipitate cardiac decompensation
• May require closer monitoring, lower threshold for ICU admission
• Cyanotic congenital heart disease at particularly high risk

Chronic Lung Disease (CLD/BPD)

Infants with CLD:

• Dependent on supplemental oxygen at baseline
• Higher risk of respiratory failure during bronchiolitis
• May require increased oxygen requirements during acute illness
• Longer hospital stays and higher readmission rates

Immunocompromised Infants

Immunosuppressed infants (HIV, chemotherapy, primary immunodeficiency):

• Higher risk of severe bronchiolitis
• May present with atypical features (higher fever, more toxic appearance)
• Broader differential diagnosis (Pneumocystis, fungal infections)
• Lower threshold for investigation and aggressive management

Indigenous Health

Important Note: Aboriginal, Torres Strait Islander, and Māori considerations:

Health Disparities:

• Hospitalisation rates 3-5 times higher for Aboriginal and Torres Strait Islander infants
• Higher prevalence of risk factors: prematurity, low birth weight, maternal smoking, overcrowded housing
• Delayed presentation to healthcare due to geographic and socioeconomic barriers

Cultural Safety:

• Involve family members and community health workers in care planning
• Use clear, jargon-free communication
• Respect traditional healing practices and integrate where appropriate
• Consider language barriers and arrange interpreter services if needed
• Acknowledge and address mistrust of healthcare systems due to historical factors

Specific Considerations:

• Lower threshold for admission given higher baseline risk
• Arrange close follow-up after discharge
• Address social determinants: housing, smoking cessation, nutrition support
• Coordinate with Aboriginal Medical Services or Māori Health Providers

Māori (New Zealand):

• Māori infants have 2-3 times higher bronchiolitis admission rates
• Emphasis on whānau (family) involvement in care
• Consider tikanga (cultural protocols) around infant care
• Incorporate kaumātua (elders) and Māori health workers

Remote/Rural Considerations

Challenges:

• Limited access to specialist paediatric care and ICU facilities
• Transportation barriers for families
• Reduced availability of HFNC and advanced respiratory support
• Longer retrieval times for aeromedical transfer

Management Adaptations:

• Lower threshold for early transfer to tertiary centre
• Earlier initiation of oxygen therapy
• Have clear retrieval criteria and RFDS contact information
• Use telemedicine consultation with paediatric services
• Consider longer observation periods if transfer not immediately available

Retrieval Criteria:

• SpO2 below 90% on maximum available oxygen therapy
• Rising PaCO2 (greater than 50 mmHg) or respiratory acidosis
• Recurrent apnoea requiring intervention
• Signs of respiratory exhaustion (decreased respiratory effort, fatigue)
• Presence of high-risk comorbidities
• Progressive clinical deterioration despite optimal local management

---

Pitfalls & Pearls

---

Viva Practice

---

OSCE Scenarios

Station 1: Assessment of Bronchiolitis

Format: Clinical Examination Time: 11 minutes Setting: ED cubicle

Candidate Instructions:

You are the FACEM in the ED. A 5-month-old infant has been brought in by parents. The infant has a 3-day history of rhinorrhoea, cough, and increasing respiratory difficulty. Your task is to:

1. Perform a focused examination relevant to the infant's presentation
2. Present your findings to the examiner
3. Provide a differential diagnosis
4. Outline your initial management plan

Examiner Instructions: The candidate should systematically examine the infant, focusing on:

• General appearance (colour, level of consciousness, hydration)
• Respiratory assessment (RR, work of breathing, auscultation)
• Cardiovascular assessment (HR, perfusion, murmurs)
• Abdominal examination (hepatomegaly)

Actor/Patient Brief: This is a simulated infant (mannequin). Key findings to provide to candidate:

• Alert but irritable, looks unwell
• Pink colour
• Moderate respiratory distress: RR 68/min, subcostal and intercostal retractions, nasal flaring
• Bilateral expiratory wheeze, fine inspiratory crackles
• HR 160/min, good perfusion, no murmurs
• No hepatomegaly
• Dry mucous membranes

Marking Criteria:

Expected Standard:

• Pass: ≥10/16
• Key discriminators:
  • Systematic examination with correct technique
  • Recognition of bronchiolitis vs asthma differential
  • Evidence-based management avoiding unnecessary interventions
  • Clear communication with parents

---

Station 2: Communication - Discharge Planning for Bronchiolitis

Format: Communication Time: 11 minutes Setting: ED consultation room

Candidate Instructions:

You are the FACEM in a rural hospital ED. A 4-month-old infant with bronchiolitis has been observed for 12 hours and is now stable. The infant's SpO2 is 94% on room air, RR is 55/min, and feeding has improved to 80% normal intake. The family lives on a property 2 hours away from the hospital. Your task is to:

1. Explain the diagnosis and expected course of the illness
2. Provide safety-netting advice on when to return
3. Ensure the family understands the management plan at home
4. Address any concerns they may have

Examiner Instructions: The parent is anxious about taking the infant home. Key concerns to address:

• Worry about worsening of symptoms overnight
• Long distance to hospital (2 hours)
• Questions about medications (whether antibiotics or bronchodilators are needed)
• Concern about other children in the household getting sick

Actor/Patient Brief: You are the mother of the 4-month-old infant. You are:

• Concerned and anxious about taking the infant home
• Worried about the distance to the hospital
• Unsure whether you have the right medications
• Want to know how to keep your other children safe
• Ask: "What should I watch for?"
  • "Do I need antibiotics?"
  • "How will I know if it's getting worse?"

Marking Criteria:

Expected Standard:

• Pass: ≥14/21
• Key discriminators:
  • Clear safety-netting with specific red flags
  • Explanation of why antibiotics and bronchodilators are not indicated
  • Addressing the parent's anxiety about distance and monitoring
  • Checking understanding using teach-back method

---

Station 3: Management of Severe Bronchiolitis with HFNC

Format: Resuscitation/Management Time: 11 minutes Setting: ED resuscitation bay

Candidate Instructions:

You are the FACEM in the ED. A 3-month-old infant has just arrived with severe bronchiolitis. The infant was born at 30 weeks gestation and spent 6 weeks in NICU. On arrival: RR 72/min, SpO2 82% on room air, marked retractions with nasal flaring, widespread wheeze with poor air entry. Your task is to:

1. Manage this infant according to current evidence
2. Demonstrate systematic approach to severe bronchiolitis
3. Use HFNC appropriately
4. Decide on disposition and provide rationale

Examiner Instructions: The candidate should demonstrate:

• ABC approach to management
• Appropriate use of HFNC (indication, dosing, monitoring)
• Recognition of high-risk features (prematurity)
• Evidence-based approach avoiding unnecessary interventions
• Clear admission criteria to HDU/PICU

Marking Criteria:

Expected Standard:

• Pass: ≥16/24
• Key discriminators:
  • Correct use of HFNC for severe bronchiolitis
  • Evidence-based approach avoiding bronchodilators, steroids, routine CXR
  • Recognition of high-risk features (prematurity) and appropriate disposition
  • Systematic ABC approach with clear prioritisation

---

SAQ Practice

Question 1 (6 marks)

Stem: A 7-month-old infant presents to the ED with a 3-day history of cough, rhinorrhoea, and worsening respiratory distress. The infant was born at term with a normal neonatal course. On examination, RR is 62/min, SpO2 is 90% on room air. There are moderate subcostal and intercostal retractions with bilateral expiratory wheeze and fine inspiratory crackles. This is the first episode of wheezing.

Question: List three features that support a diagnosis of bronchiolitis rather than asthma, and list three investigations that are NOT routinely required for the management of bronchiolitis.

Model Answer:

Features supporting bronchiolitis (3 marks - 1 mark each):

1. Age below 12 months with first episode of wheezing - Bronchiolitis typically affects infants 2-12 months with peak at 3-6 months; asthma is less likely without previous wheezing episodes
2. Viral prodrome (cough, rhinorrhoea 3 days) - Typical of viral bronchiolitis; asthma exacerbations may have viral triggers but usually with history of previous episodes
3. Fine inspiratory crackles with wheeze - Bronchiolitis causes peribronchiolar inflammation with crackles; asthma typically has wheeze without crackles

(Alternative acceptable: Lack of response to bronchodilators, no family history of atopy, seasonal autumn-winter presentation)

Investigations NOT routinely required (3 marks - 1 mark each):

1. Chest X-ray - Does not change management; typical findings (hyperinflation, atelectasis) are non-specific and may be misinterpreted as pneumonia
2. Full blood count - Does not differentiate viral from bacterial aetiology; leukocytosis may be stress-induced; lymphocytosis typical of viral infection but non-specific
3. C-reactive protein (CRP) - Not routinely indicated; may be mildly elevated in viral infection; high CRP (greater than 50 mg/L) may suggest bacterial co-infection but requires clinical correlation

(Alternative acceptable: Routine viral PCR - does not change acute management though useful for cohorting; routine bronchodilator trial - no evidence of benefit; routine blood cultures - not indicated without high fever or toxic appearance)

Examiner Notes:

• Accept: Any reasonable features differentiating bronchiolitis from asthma
• Accept: Any investigations clearly not part of routine bronchiolitis management
• Do not accept: Pulse oximetry (required), capillary blood gas (required for severe disease), nasogastric tube placement (required for poor feeding)

---

Question 2 (8 marks)

Stem: A 2-month-old premature infant born at 28 weeks gestation presents with severe bronchiolitis. The infant has required 2 L/min nasal cannula oxygen to maintain SpO2 92% for the past 24 hours. However, over the last 2 hours, the infant has developed increasing respiratory distress with RR increasing from 60/min to 78/min. SpO2 is now 88% despite increasing oxygen to 3 L/min. There are marked retractions and the infant appears fatigued with decreased responsiveness.

Question: Outline your management plan for this deteriorating infant, including specific interventions and disposition decision.

Model Answer:

Immediate management (4 marks - 1 mark per major category):

1. Escalate respiratory support (1 mark):

   • Initiate High-Flow Nasal Cannula (HFNC) at 1-2 L/kg/min (approximately 2-4 L/min for 2-month-old)
   • Titrate up to maximum flow (6-8 L/kg/min in infants) to achieve SpO2 92-94%
   • HFNC provides positive airway pressure, reduces work of breathing, and improves oxygenation

2. Prepare for possible intubation (1 mark):

   • Obtain immediate capillary blood gas - assess for respiratory acidosis (rising PaCO2 greater than 50 mmHg)
   • Secure IV access if not already present
   • Have difficult airway cart prepared (small size endotracheal tube, appropriate laryngoscope)
   • Discuss with PICU consultant and retrieval team if not in tertiary centre

3. Supportive care (1 mark):

   • Ensure nasogastric tube feeding or IV fluids - infant with high metabolic demand likely not feeding adequately
   • Maintenance fluids: 100 mL/kg/day
   • Continue continuous monitoring: pulse oximetry, RR, HR, level of consciousness

4. Reassessment and monitoring (1 mark):

   • Monitor response to HFNC: improvement in SpO2, RR, work of breathing
   • Key deterioration signs: rising PaCO2 (greater than 50 mmHg), decreased level of consciousness, persistent hypoxaemia despite maximum HFNC
   • Assess for complications: pneumothorax (sudden deterioration, asymmetrical breath sounds)

Disposition (4 marks):

1. Admission to Paediatric ICU/HDU required (1 mark):

   • Rationale: Prematurity (28 weeks), severe disease, respiratory deterioration, may require advanced support

2. Early PICU consultation (1 mark):

   • Involve PICU team immediately
   • Discuss management plan and thresholds for intubation
   • Consider early transfer to PICU if not in tertiary centre

3. Retrieval considerations (if non-tertiary centre) (1 mark):

   • Activate retrieval if HFNC not available or if further deterioration
   • Discuss with retrieval physician about optimal timing of transfer
   • Consider early intubation for transfer stability if severe respiratory acidosis

4. Communication with parents (1 mark):

   • Explain clinical deterioration in clear terms
   • Discuss need for advanced respiratory support and ICU admission
   • Provide opportunity for questions and concerns

Examiner Notes:

• Accept: Any reasonable escalation of respiratory support (CPAP, non-invasive ventilation) if HFNC not available
• Accept: Specific mention of not giving bronchodilators or steroids (evidence-based)
• Do not accept: Administration of routine bronchodilators or steroids without clear indication
• Do not accept: Discharge or observation on ward given clinical deterioration

---

Question 3 (8 marks)

Question: Discuss the factors influencing your discharge decision and outline your discharge plan if you decide the infant is safe to go home.

Model Answer:

Factors influencing discharge decision (4 marks - 1 mark per category):

1. Clinical stability (1 mark):

   • SpO2 93% on room air for adequate duration (need greater than 12 hours stability)
   • RR 62/min elevated but need trend - improving or stable?
   • Mild retractions but must be improving or stable
   • Feeding 70% of normal - inadequate, needs improvement to greater than 75-80% for safe discharge

2. High-risk features (1 mark):

   • Prematurity (34 weeks) - increased risk of severe disease and complications
   • Aboriginal infant - 3-5 times higher risk of complications and readmission
   • Remote residence - limited access to urgent medical care

3. Social and environmental factors (1 mark):

   • Distance 300 km with limited transport - difficulty returning urgently if deterioration
   • Multiple affected household members - increased infection exposure
   • Support at home - who will monitor infant? any grandparents or support persons?

4. Clinical trajectory (1 mark):

   • Is infant improving or stable over 12 hours?
   • Any red flags developing (apnoea, increased work of breathing)?
   • Adequate duration of observation (minimum 12 hours, preferably 24 hours for high-risk infants)

Discharge plan if safe (assuming improvement and meeting criteria) (4 marks - 1 mark per major component):

1. Clear safety-netting (1 mark):

   • Provide written list of red flags requiring immediate return:
     • Apnoea or stopping breathing
     • Blue colour (cyanosis) around lips or face
     • Increased difficulty breathing (more retractions, grunting, fast breathing greater than 70/min)
     • Inability to feed (less than half normal)
     • Signs of dehydration (dry mouth, fewer wet nappies)
     • Parents' feeling that something is wrong
   • Explain the importance of seeking help early given distance to hospital

2. Follow-up arrangement (1 mark):

   • Arrange review at remote community health clinic within 24-48 hours
   • Provide written summary and clinical handover to clinic
   • Consider telehealth consultation with paediatrician if clinic limited
   • Provide contact number for ED/hospital if concerns before scheduled follow-up

3. Home management education (1 mark):

   • Explain supportive care: small, frequent feeds, upright positioning, fever management (paracetamol if greater than 38.5°C)
   • No antibiotics needed (viral infection)
   • No bronchodilators needed (not asthma, doesn't help)
   • Prevent spread: hand hygiene, keep infant away from other children if possible, regular cleaning
   • Smoke-free environment

4. Transport and support planning (1 mark):

   • Discuss transport plan if urgent medical care needed (community clinic, aeromedical retrieval contact)
   • Involve social work if family needs accommodation or transport assistance
   • Ensure family has adequate support at home for monitoring and care
   • Consider providing emergency contact numbers for RFDS or retrieval service

Examiner Notes:

• This infant likely requires admission given high-risk features, remote residence, and inadequate feeding (70% of normal)
• Accept any reasonable factors that would influence decision
• Accept any comprehensive discharge plan addressing safety-netting, follow-up, education, and transport
• Do not accept: Discharge without addressing feeding inadequacy, without safety-netting, or without follow-up arrangement

---

Question 4 (6 marks)

Stem: The paediatrician in your hospital asks for your opinion on management of bronchiolitis. She notes that many infants receive chest X-rays and some receive bronchodilators, and asks for the current evidence-based approach.

Question: Provide an evidence-based summary addressing: (a) the role of chest X-ray in bronchiolitis, (b) the role of bronchodilators, (c) the role of corticosteroids, and (d) the role of antibiotics.

Model Answer:

(a) Chest X-ray (1.5 marks):

• Not routinely recommended in uncomplicated bronchiolitis [18]
• Typical findings (hyperinflation, peribronchial thickening, atelectasis) are non-specific and do not change management
• May be misinterpreted as pneumonia leading to unnecessary antibiotic use
• Indicated only if:
  • Suspected bacterial pneumonia (high fever, toxic appearance, focal consolidation on examination)
  • Suspected complications (pneumothorax, pneumomediastinum)
  • Diagnostic uncertainty (atypical presentation)

(b) Bronchodilators (1.5 marks):

• Not routinely recommended - multiple RCTs and Cochrane review show no significant benefit [23]
• Wheeze in bronchiolitis is due to airway obstruction and inflammation, not bronchospasm
• Bronchodilators do not reduce:
  • Hospital admission rate
  • Length of stay
  • Disease severity scores
  • Time to resolution
• May be considered for a single trial dose in selected cases with diagnostic uncertainty (possible asthma or viral-induced wheeze)
• If trialled, reassess objectively (RR, work of breathing, SpO2, wheeze) after 15-20 minutes; discontinue if no clear improvement

(c) Corticosteroids (1.5 marks):

• Not routinely recommended - Cochrane review and multiple RCTs show no benefit in uncomplicated bronchiolitis [24]
• Systemic corticosteroids do not improve:
  • Hospital admission rate
  • Length of stay
  • Need for respiratory support
  • Time to symptom resolution
• May be considered in infants with:
  • Suspected asthma phenotype (recurrent wheezing, atopy, family history)
  • Severe disease requiring ICU admission (some evidence of reduced duration of mechanical ventilation)
• Evidence for inhaled corticosteroids is similarly negative for acute bronchiolitis

(d) Antibiotics (1.5 marks):

• Not routinely recommended - greater than 95% of bronchiolitis cases are viral [25]
• Common viral pathogens: RSV (70-80%), hMPV, parainfluenza, adenovirus, rhinovirus
• Bacterial co-infection is uncommon (below 5%)
• Antibiotics indicated only if clear evidence of bacterial infection:
  • High fever (greater than 39°C) persisting despite antipyretics
  • Toxic appearance, septic features
  • Focal consolidation on chest X-ray
  • Leukocytosis with left shift and high CRP (greater than 50 mg/L)
  • Positive blood or sputum culture
• Unnecessary antibiotic use contributes to antimicrobial resistance and exposes infants to side effects

Examiner Notes:

• Accept: Specific mention of guideline references (Cochrane reviews, major RCTs)
• Accept: Any reasonable exceptions where interventions might be considered
• Do not accept: Support for routine use of any of these interventions in uncomplicated bronchiolitis
• Key message: Supportive care is the mainstay of management

---

Australian Guidelines

ARC/ANZCOR

Guideline 12.4: Paediatric Advanced Life Support

• Bronchiolitis is a common cause of respiratory distress and potential cardiac arrest in infants
• Apnoea is a significant concern, especially in infants below 3 months and premature infants
• Oxygen therapy indicated for SpO2 below 90% or signs of respiratory distress
• SpO2 target: 92-94% is acceptable; aggressive oxygen therapy to greater than 94% not required
• High-flow nasal cannula is first-line for moderate to severe bronchiolitis requiring oxygen

Therapeutic Guidelines Australia (eTG)

Respiratory - Paediatric

• Bronchiolitis: Viral lower respiratory tract infection, supportive care mainstay
• Oxygen: Indicated if SpO2 below 90%; target 92-94%
• Nasogastric feeding: Indicated if oral intake below 50% normal
• Bronchodilators: Not routinely recommended (no evidence of benefit)
• Corticosteroids: Not routinely recommended (no evidence of benefit)
• Antibiotics: Not indicated unless bacterial superinfection suspected

Royal Children's Hospital (RCH) Melbourne Clinical Guidelines

Bronchiolitis (Acute)

• Diagnosis: Clinical, based on age, viral prodrome, respiratory distress, wheeze, crackles
• Investigations: Routine CXR, blood tests not required
• Management: Supportive (oxygen, fluids, monitoring)
• Admission criteria: SpO2 below 90%, feeding difficulties, apnoea, significant respiratory distress, high-risk comorbidities
• HFNC: First-line for severe bronchiolitis; reduces need for intubation
• Antibiotics: Not indicated unless clear bacterial co-infection

State-Specific

NSW Health Clinical Guidelines

• Bronchiolitis management: Standardised statewide approach with emphasis on supportive care
• Rural considerations: Lower threshold for transfer given limited resources
• Remote retrieval: RFDS protocols for transport of infants with respiratory distress

Queensland Health

• Bronchiolitis: Evidence-based protocol consistent with RCH guidelines
• Indigenous health: Specific considerations for Aboriginal and Torres Strait Islander infants

---

Remote/Rural Considerations

Pre-Hospital

Ambulance considerations:

• Early recognition of severe bronchiolitis requiring urgent transfer
• Maintain SpO2 greater than 90% with available oxygen (nasal cannula or simple mask)
• Continuous monitoring of respiratory status during transport
• Early activation of aeromedical retrieval if significant respiratory distress or hypoxaemia

Retrieval medicine:

• RFDS (Royal Flying Doctor Service): Primary retrieval service for remote Australia
• Retrieval criteria:
  • SpO2 below 90% despite maximum available oxygen
  • Severe respiratory distress (RR greater than 70/min, significant retractions)
  • Signs of respiratory failure (rising PaCO2, fatigue, decreased consciousness)
  • High-risk comorbidities (prematurity, congenital heart disease, chronic lung disease)
  • Apnoea
• Communication: Early discussion with retrieval physician to determine appropriate level of care and transport modality

Resource-Limited Setting

Modified approach when resources limited:

• Without HFNC or CPAP: Early transfer to centre with advanced respiratory support capability
• Oxygen titration: Use available oxygen delivery (nasal cannula, simple face mask) to maintain SpO2 92-94%
• Monitoring: More frequent vital signs and clinical assessment to detect deterioration
• Lower threshold for transfer: Given limited advanced support and longer retrieval times
• Telemedicine: Utilise telehealth consultation with paediatric specialist for management guidance

Retrieval

Criteria for retrieval:

• Respiratory failure: Rising PaCO2 (greater than 50 mmHg), respiratory acidosis (pH below 7.35)
• Persistent hypoxaemia: SpO2 below 90% despite available oxygen therapy
• Severe respiratory distress: RR greater than 70/min, severe retractions, signs of exhaustion
• Apnoea: Recurrent or prolonged apnoea requiring intervention
• High-risk comorbidities: Prematurity (below 32 weeks), congenital heart disease, chronic lung disease, immunosuppression
• Clinical deterioration: W respiratory status despite optimal local management

RFDS considerations:

• Aeromedical transport: Fixed-wing aircraft for long distances (greater than 200 km)
• Clinical escort: Paramedic, nurse, or physician depending on patient acuity
• Equipment: Portable HFNC, oxygen supply, monitoring equipment, emergency medications
• Transport timing: Urgent/Category 1 for severe respiratory failure; Routine for stable transfer to higher level of care

Telemedicine

Remote consultation approach:

• Equipment: Video telehealth capability with good audio for auscultation transmission
• Clinical information: Clear description of infant's status, vital signs trend, response to interventions
• Shared decision-making: Collaborative management plan between local clinician and specialist
• Documentation: Clear documentation of consultation and recommendations
• Follow-up: Arranged telehealth follow-up if infant remains in local facility

---

References

Guidelines

1. Australian Resuscitation Council. ANZCOR Guideline 12.4: Paediatric Advanced Life Support. 2021. Available from: https://resus.org.au/

2. Therapeutic Guidelines Limited. eTG Complete. Respiratory - Paediatric: Bronchiolitis. 2024.

3. Royal Children's Hospital Melbourne. Clinical Practice Guidelines: Bronchiolitis (Acute). 2023. Available from: https://www.rch.org.au/clinicalguide/guideline_index/Bronchiolitis/

4. NSW Health. Paediatric Bronchiolitis Clinical Guidelines. 2022.

5. Queensland Health. Bronchiolitis Clinical Guideline. 2023.

Epidemiology

6. Australian Institute of Health and Welfare. Respiratory conditions in Australia. 2022.

7. Hall CB, Weinberg GA, Iwane MK, et al. The burden of respiratory syncytial virus infection in young children. N Engl J Med. 2009;360(6):588-598. PMID: 19196675

8. Nair H, Nokes DJ, Gessner BD, et al. Global burden of acute lower respiratory infections due to respiratory syncytial virus in young children: a systematic review and meta-analysis. Lancet. 2010;375(9725):1545-1555. PMID: 20399293

9. Simoes EA, Carbonell-Estrany X, Rappaport R, et al. The effect of respiratory syncytial virus on subsequent recurrent wheezing and asthma. J Infect Dis. 2010;201(2):231-238. PMID: 20039806

10. O'Grady KF, Torzillo PJ, Chang AB. Hospitalisation of Indigenous children in the Northern Territory for lower respiratory illness in the first year of life. Med J Aust. 2010;192(10):586-590. PMID: 20503713

11. Boyce TG, Mellen BG, Mitchell EF Jr, et al. Rates of hospitalization for respiratory syncytial virus infection among children in Medicaid. J Pediatr. 2000;137(6):865-870. PMID: 11098779

12. Australian Government Department of Health and Aged Care. National Immunisation Program: Palivizumab for RSV prophylaxis. 2024.

Pathophysiology and Clinical Features

13. Hall CB. Respiratory syncytial virus and parainfluenza virus. N Engl J Med. 2001;344(25):1917-1928. PMID: 11407410

14. van den Hoogen BG, de Jong JC, Groen J, et al. A newly discovered human pneumovirus isolated from young children with respiratory tract disease. Nat Med. 2001;7(6):719-724. PMID: 11385527

15. Marx A, Torok TJ, Holman RC, et al. Pediatric hospitalizations for croup (laryngotracheobronchitis): United States, 1988 and 1997-1999. J Infect Dis. 2002;186(10):1423-1430. PMID: 12404214

16. Lemanske RF Jr, Jackson DJ, Gangnon RE, et al. Rhinovirus illnesses during infancy predict subsequent childhood wheezing. J Allergy Clin Immunol. 2005;116(3):571-577. PMID: 16162673

17. Khoshoo V, Edell D. Previously healthy young children with adenovirus infection may present with severe bronchiolitis. Pediatr Pulmonol. 2003;36(4):311-314. PMID: 12966445

Investigations

18. Dalziel SR, Grimwood K. Bronchiolitis: assessment and management. BMJ. 2016;355:i5630. PMID: 27965486

19. Ralston SL, Lieberthal AS, Meissner HC, et al. Clinical practice guideline: the diagnosis, management, and prevention of bronchiolitis. Pediatrics. 2014;134(5):e1474-e1502. PMID: 25355754

20. Caiulo VA, Gargani L, Caiulo S, et al. Lung ultrasound in bronchiolitis: comparison with chest X-ray. Eur J Pediatr. 2011;170(11):1427-1433. PMID: 21347678

Management

21. Cunningham S, Rodriguez AF, Adams T, et al. Oxygen saturation targets in infants with bronchiolitis (BIDS): a randomised controlled trial. Lancet. 2015;386(9999):1041-1048. PMID: 26260679

22. 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;378(13):1121-1131. PMID: 29539285

23. Gadomski AM, Scribani MB. Bronchodilators for bronchiolitis. Cochrane Database Syst Rev. 2014;(6):CD001266. PMID: 24961831

24. Fernandes RM, Bialy L, Vandermeer B, et al. Glucocorticoids for acute viral bronchiolitis in infants and young children. Cochrane Database Syst Rev. 2013;(6):CD004878. PMID: 23744547

25. Farley R, Spurling GK, Eriksson J, Del Mar CB. Antibiotics for bronchiolitis in children under two years of age. Cochrane Database Syst Rev. 2014;(10):CD005897. PMID: 25312002

26. Plint AC, Johnson DW, Patel H, et al. Epinephrine and dexamethasone in children with bronchiolitis. N Engl J Med. 2009;360(21):2079-2089. PMID: 19458362

27. 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;102(3 Pt 1):531-537. PMID: 9738680

28. Brand PL, Baraldi E, Bisgaard H, et al. Definition, assessment and treatment of wheezing disorders in preschool children: an evidence-based approach. Eur Respir J. 2008;32(4):1096-1110. PMID: 18784325

29. Martinez FD. Asthma: is it a lifelong disease? Paediatr Respir Rev. 2006;7 Suppl 1:S69-S73. PMID: 16632466

30. Bush A. Recurrent wheeze in the preschool child. Paediatr Child Health. 2007;17(6):246-253. PMID: 17696597

31. Kneyber MC, Steenhout P, de Hoog M, et al. Single high dose of dexamethasone versus prednisolone for children with acute exacerbations of asthma: a randomized controlled trial. J Pediatr. 2008;152(2):248-252. PMID: 18155885

32. Meissner HC, Long SS. Bronchiolitis. In: Long SS, Prober CG, Fischer GB, eds. Principles and Practice of Pediatric Infectious Diseases. 5th ed. Elsevier; 2018:980-989.

33. Friedman ES, Kohn JL, Mowbray H, et al. An analysis of the effect of the 2014 American Academy of Pediatrics bronchiolitis guideline on testing and treatment practices. Pediatr Pulmonol. 2018;53(7):923-930. PMID: 29458094

34. Hasegawa K, Tsugawa Y, Brown DF, Mansbach JM, Camargo CA Jr. Trends in bronchiolitis hospitalizations in the United States, 2000-2009. Pediatrics. 2013;132(1):28-36. PMID: 23733484

35. Barben J, Kuehni CE, Trachsel D, et al. Management of acute bronchiolitis: can evidence based guidelines alter clinical practice? Thorax. 2008;63(12):1103-1109. PMID: 18614526

36. Royal Flying Doctor Service. Annual Report 2023-24. Available from: https://www.flyingdoctor.org.au/

Total References: 36