14  Bronchiolitis

Published

May 30, 2025

14.1 Introduction

Bronchiolitis is a common viral infection of the lower respiratory tract that primarily affects infants and young children. It is the leading cause of hospitalization for children under 2 years of age worldwide. In Ghana and other sub-Saharan African countries, bronchiolitis significantly contributes to infant morbidity and mortality, especially during the harmattan season when respiratory infections are more prevalent.

Understanding bronchiolitis is essential for medical students, particularly in environments where diagnostic tools are scarce and treatment depends largely on clinical skills and supportive care.

14.2 Definition

Bronchiolitis is defined as an acute viral infection of the lower respiratory tract, primarily affecting the bronchioles. It leads to inflammation, edema, and increased mucus production, resulting in airway obstruction, wheezing, and respiratory distress.

14.3 Epidemiology

  • Age group: Primarily affects children under 2 years, most commonly under 6 months
  • Peak incidence: During the cold and dry months (November to February in Ghana)
  • Transmission: Highly contagious; spread via respiratory droplets, direct contact, or contaminated surfaces
  • High-risk groups:
    • Premature infants
    • Infants with congenital heart disease
    • Children with chronic lung disease
    • Immunocompromised children
    • Children exposed to tobacco smoke or indoor air pollution

14.4 Etiology (Causative Agents)

The most common cause is Respiratory Syncytial Virus (RSV), responsible for 50–80% of cases.

Other viruses:

  • Human metapneumovirus
  • Parainfluenza virus
  • Influenza virus
  • Rhinovirus
  • Adenovirus
  • Coronavirus

14.5 Pathophysiology

  1. Viral infection of the nasal and lower respiratory epithelium
  2. Inflammation and edema of the bronchioles
  3. Necrosis and sloughing of epithelial cells
  4. Increased mucus production and plugging of small airways
  5. Air trapping and hyperinflation, leading to:
    • Increased work of breathing
    • Impaired gas exchange
    • Hypoxia and, in severe cases, respiratory failure

14.6 Clinical Features

History

  • Starts as an upper respiratory tract infection (e.g., runny nose, mild cough)
  • Progresses over 2–3 days to:
    • Cough
    • Tachypnea
    • Wheezing
    • Poor feeding
    • Apnea (especially in premature or very young infants)
    • Fever (may or may not be present

Examination

  • Tachypnea
  • Nasal flaring
  • Chest retractions (intercostal, subcostal, suprasternal)
  • Wheezing and crackles on auscultation
  • Hypoxia (low oxygen saturation)
  • Dehydration
  • Cyanosis in severe cases

14.7 Differential Diagnosis

Condition Key Features
Asthma Older children (>2 years), recurrent episodes, personal/family history of atopy
Pneumonia Fever, focal crackles, lobar consolidation on chest X-ray
Foreign body aspiration Sudden onset, localized wheeze, asymmetric breath sounds
Congenital heart disease Cyanosis, poor weight gain, murmur
Pertussis Paroxysmal cough, whoop, post-tussive vomiting

14.8 Diagnosis

Clinical diagnosis is key in most settings, especially where investigations are limited.

Investigations (if available)

  • Pulse oximetry: Assess oxygen saturation
  • Chest X-ray (not routinely indicated): May show hyperinflation, peribronchial thickening, patchy atelectasis
  • Nasopharyngeal swab for viral testing (e.g., RSV) – rarely available in Ghana
  • Complete blood count: To rule out bacterial infection if fever is high or toxic appearance
  • Serum electrolytes: In severely ill or dehydrated children

14.9 Severity Assessment

Mild

  • Normal feeding
  • Mild tachypnea, minimal retractions
  • Oxygen saturation ≥ 92%

Moderate

  • Poor feeding
  • Moderate tachypnea and retractions
  • Wheezing or crackles
  • Oxygen saturation 90–92%

Severe

  • Marked retractions, grunting, nasal flaring
  • Apnea
  • Cyanosis
  • Oxygen saturation < 90%
  • Lethargy or altered mental status

14.10 Management

14.10.1 General Principles

  • Most cases are self-limiting and can be managed with supportive care
  • Hospitalization is required for:
    • Moderate to severe disease
    • Apnea
    • Inability to feed
    • Oxygen saturation < 90%
    • High-risk infants

14.10.2 Outpatient (Home-Based) Management

  • Ensure adequate hydration and feeding
  • Educate caregivers on danger signs:
    • Rapid breathing
    • Chest in-drawing
    • Inability to feed
    • Cyanosis
    • Lethargy
  • Clear nasal secretions with saline drops/suction
  • Follow-up in 24–48 hours

14.10.3 Inpatient (Hospital) Management

1. Supportive Care

  • Oxygen therapy:
    • Give oxygen if SpO₂ < 90%
    • Via nasal prongs or face mask
  • Hydration and nutrition:
    • Encourage breastfeeding or oral feeds
    • NG tube feeding or IV fluids if unable to feed orally
  • Monitoring:
    • Respiratory rate
    • Oxygen saturation
    • Fluid status
    • Level of consciousness

14.10.4 Medications (Avoid routine use)

Medication Recommendation
Bronchodilators (e.g., salbutamol) Not routinely recommended; trial may be considered in wheezing children >12 months
Steroids Not beneficial in uncomplicated bronchiolitis
Antibiotics Not indicated unless bacterial co-infection suspected (e.g., pneumonia, otitis media)
Nebulized hypertonic saline Limited evidence; not routinely used in Ghana
Antiviral agents Not routinely available or used in Ghana

14.11 Complications

  • Apnea
  • Respiratory failure
  • Dehydration and poor nutrition
  • Secondary bacterial infections
  • Recurrent wheezing or asthma-like episodes later in life
  • Death (in severe, untreated cases, particularly in high-risk infants)

14.12 Prevention

1. Infection Control

  • Hand hygiene
  • Avoid crowding, especially in daycares and nurseries
  • Educate caregivers on cough etiquette

2. Breastfeeding

  • Exclusive breastfeeding for the first 6 months provides protective antibodies

3. Avoid Smoke Exposure

  • Avoid smoking near infants
  • Reduce indoor air pollution (e.g., smoke from firewood)

4. Immunization

  • Ensure up-to-date vaccination, especially:
    • Influenza vaccine
    • Pneumococcal vaccine
    • Pertussis vaccine

5. Prophylaxis (Palivizumab)

  • A monoclonal antibody used for RSV prophylaxis
  • Expensive and not readily available in Ghana
  • Considered only for very high-risk infants in specialized centers

14.13 Prognosis

  • Most children recover fully within 7–10 days
  • Cough may persist for 2–3 weeks
  • Infants with severe disease may have recurrent wheezing or asthma

14.14 Special Considerations in Ghana

  • Overcrowded homes and poor air quality increase risk
  • Health-seeking behavior may be delayed due to cultural beliefs or access issues
  • Resource limitations often mean:
    • Reliance on clinical diagnosis
    • Limited access to oxygen and pulse oximetry
  • Need for education of caregivers about early signs of respiratory distress
  • Emphasize community-based health interventions (e.g., CHPS compounds)

14.15 Case Scenario

Case: 4-month-old male infant

Presentation:

  • 3-day history of cough, runny nose, and poor feeding
  • Developed fast breathing and wheezing today
  • No fever
  • No significant past medical history

On examination:

  • RR: 68 breaths/min
  • Chest retractions present
  • O₂ saturation: 88% on room air
  • Nasal flaring, scattered wheeze

Diagnosis:

  • Likely moderate to severe bronchiolitis

Management:

  • Admit for supportive care
  • Oxygen via nasal prongs
  • NG tube feeding due to poor suck
  • Monitor vitals and oxygen saturation
  • Educate mother on hand hygiene and signs of deterioration

14.16 Summary Table

Feature Bronchiolitis
Age group < 2 years (commonest < 6 months)
Onset Gradual, following URTI
Common virus RSV
Main symptoms Cough, wheeze, tachypnea, and feeding difficulty
Diagnosis Clinical
Mainstay of treatment Supportive care
Antibiotics Not routinely indicated
Oxygen If SpO₂ < 90%
Prognosis Excellent in most cases

14.17 Conclusion

Bronchiolitis is a common and potentially severe illness affecting infants and young children in Ghana. Early recognition and supportive management are essential to preventing complications. Medical students need to be familiar with its presentation, clinical evaluation, and evidence-based treatment, especially in resource-limited healthcare settings where advanced diagnostics may not be available.