Case studies · Paediatrics · 13 November 2026

Bronchiolitis case study

The case

Patient: A 4‑month‑old male infant, exclusively breast‑fed, born at term (38 weeks) with a birth weight of 3.2 kg. No perinatal complications. No known allergies. No prior hospitalizations.

Presenting complaint: Progressive cough and noisy breathing for 3 days.

History of present illness:

• Onset: 3 days ago, mother noticed a mild, non‑productive cough that was initially intermittent.
• Progression: Over the past 48 hours the cough has become more frequent, associated with audible wheezing and a “high‑pitched” inspiratory squeak (stridor‑like).
• Feeding: The infant has become increasingly irritable during feeds and has taken only about 50 % of his usual volume in the last 24 hours.
• Fever: Low‑grade fever recorded at home, 38.0 °C on day 2, now afebrile.
• Nasal symptoms: Clear nasal discharge and mild congestion. No vomiting, diarrhea, or rash.

Past medical history: Up‑to‑date immunizations, including the first dose of palivizumab (not given as infant is not high‑risk). No previous wheeze or asthma.

Family history: Mother has allergic rhinitis; no asthma or atopy in immediate family.

Social history: Lives with parents and a 2‑year‑old sibling who recently had an upper respiratory infection. No tobacco smoke exposure.

Examination (at presentation to the emergency department):

Initial investigations:

The infant meets the typical age range (≤ 2 years) and clinical picture for bronchiolitis, with RSV confirmed on rapid testing.

Questions

1. What is the most likely diagnosis?
2. Which clinical and investigative findings support this diagnosis, and why are they pathognomonic?
3. According to the latest (2023) American Academy of Pediatrics (AAP) guideline, what are the recommended investigations and when are they indicated?
4. Outline the evidence‑based management plan for this patient, including supportive measures and criteria for hospital admission.
5. What are the potential complications of bronchiolitis, and how should they be monitored or prevented?

Answers

1. What is the most likely diagnosis?

Bronchiolitis – an acute viral lower respiratory tract infection of infants and young children, most commonly caused by RSV. The diagnosis is clinical, supported by age < 2 years, a prodrome of upper respiratory symptoms followed by progressive cough, wheeze, and inspiratory “squeak,” plus hypoxia and radiographic hyperinflation.

2. Which clinical and investigative findings support this diagnosis, and why are they pathognomonic?

Collectively, these features fulfill the AAP definition of bronchiolitis: “A viral infection of the lower respiratory tract in children < 2 years, characterized by a prodrome of upper respiratory symptoms followed by progressive cough, tachypnea, wheezing, and crackles.”

3. According to the latest (2023) American Academy of Pediatrics (AAP) guideline, what are the recommended investigations and when are they indicated?

Thus, the investigations performed are largely in line with the guideline; none are mandatory for uncomplicated bronchiolitis, but they help assess severity and exclude complications.

4. Outline the evidence‑based management plan for this patient, including supportive measures and criteria for hospital admission.

A. Initial assessment and disposition

• Severity assessment (based on AAP 2023):
  • Mild: RR < 60, SpO₂ ≥ 94 % on room air, no feeding difficulty.
  • Moderate: RR ≥ 60, SpO₂ 90‑93 % on room air, mild to moderate feeding difficulty.
  • Severe: RR > 70, SpO₂ < 90 % despite O₂, marked retractions, apnea, or poor perfusion.

The infant has RR 58 (borderline), SpO₂ 92 %, moderate retractions, and feeding difficulty → moderate disease. Hospital admission is recommended for close monitoring, supplemental oxygen, and hydration.

B. Supportive care

C. Monitoring

• Continuous pulse oximetry while hospitalized.
• Re‑assess respiratory rate, work of breathing, and feeding every 2‑4 hours.
• Repeat blood gas only if clinical deterioration.

D. Discharge criteria

• SpO₂ ≥ 94 % on room air for ≥ 12 hours.
• Stable respiratory rate (< 50 breaths/min) and no retractions.
• Adequate oral intake (> 80 % of usual) for at least 6 hours.
• Caregiver education on signs of worsening (increased work of breathing, feeding intolerance, cyanosis).

E. Follow‑up

• Outpatient review within 48‑72 hours or sooner if symptoms recur.

5. What are the potential complications of bronchiolitis, and how should they be monitored or prevented?

Prompt recognition and supportive care are the mainstays of preventing progression to these complications.

Key learning points

• Bronchiolitis is a clinical diagnosis in infants < 2 years, most commonly caused by RSV; the hallmark is a progressive cough with inspiratory “squeak” and wheeze after a viral prodrome.
• Severity assessment (mild, moderate, severe) guides disposition; SpO₂ < 94 % on room air or feeding difficulty warrants hospitalization.
• The 2023 AAP guideline emphasizes supportive care only: oxygen to maintain SpO₂ ≥ 94 %, adequate hydration, and careful monitoring; bronchodilators, steroids, and antibiotics are not routinely recommended.
• Routine investigations are limited; chest X‑ray and blood gases are reserved for severe or atypical cases. Rapid viral testing is optional but useful for infection control.
• Complications include respiratory failure, apnea, secondary bacterial infection, and dehydration; early detection through continuous monitoring can prevent morbidity.
• Prevention strategies focus on hand hygiene, avoiding tobacco smoke exposure, and RSV prophylaxis (palivizumab) for high‑risk infants only.
• Parents should be educated on warning signs (increased work of breathing, poor feeding, cyanosis) and the expected disease course (usually 7‑10 days).

Practice MCQs

1. A 5‑month‑old infant with bronchiolitis has a SpO₂ of 93 % on room air, a respiratory rate of 62 breaths/min, and is feeding poorly. According to the AAP 2023 guideline, the most appropriate next step is:

A. Start nebulized albuterol and discharge home.
B. Admit for observation, start humidified low‑flow oxygen, and initiate NG feeds.
C. Begin oral amoxicillin for presumed bacterial superinfection.
D. Perform a chest CT scan to rule out pneumonia.

Answer: B — The infant has moderate disease (SpO₂ < 94 %, feeding difficulty). Hospital admission for oxygen supplementation and hydration is indicated; bronchodilators and antibiotics are not routinely recommended, and a CT scan is unnecessary.

2. Which of the following statements about the use of corticosteroids in bronchiolitis is correct?

A. Systemic steroids reduce the length of hospital stay by > 2 days.
B. Inhaled steroids are recommended for all infants with wheeze.
C. Corticosteroids have no proven benefit in typical RSV bronchiolitis.
D. A single dose of dexamethasone is mandatory before discharge.

Answer: C — Multiple randomized controlled trials and meta‑analyses have shown no clinically significant benefit of corticosteroids in uncomplicated RSV bronchiolitis.

3. Which of the following is a recognized risk factor that would qualify an infant for RSV prophylaxis with palivizumab?

A. Full‑term birth with no comorbidities.
B. Age 6 months with a history of mild bronchiolitis.
C. Prematurity ≤ 28 weeks gestation and age < 12 months at the start of RSV season.
D. Exclusive breastfeeding.

Answer: C — Palivizumab is indicated for infants born ≤ 28 weeks gestation (or ≤ 29 weeks in some guidelines) who are < 12 months old at the onset of RSV season, as they are at high risk for severe disease.

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