What is the management of protracted bacterial bronchitis?

Management of Protracted Bacterial Bronchitis (PBB)

Protracted bacterial bronchitis should be treated with a 2-week course of antibiotics targeting common respiratory bacteria, with extension to 4 weeks if cough persists after initial treatment. 1

Definition and Diagnosis

Protracted bacterial bronchitis (PBB) is defined by three key criteria:

1. Presence of chronic wet cough (>4 weeks duration)
2. Response to antibiotics with cough resolution within 2 weeks
3. Absence of other causes of wet/productive cough

PBB is further classified as:

• Clinically-based PBB: Diagnosis based on clinical presentation and response to antibiotics
• Microbiologically-based PBB: Confirmed by lower airway samples showing clinically important density of respiratory bacteria (≥10⁴ CFU/mL) 1

Initial Management Approach

First-line Treatment

• Antibiotic choice: Amoxicillin-clavulanate is the most commonly used antibiotic 1
• Duration: Initial 2-week course (Grade 1A recommendation) 1
• Target organisms: Treatment should target common respiratory pathogens:
  • Haemophilus influenzae (most common, typically non-typeable)
  • Streptococcus pneumoniae
  • Moraxella catarrhalis 1

Persistent Symptoms

• If wet cough persists after 2 weeks of appropriate antibiotics, extend treatment for an additional 2 weeks (total 4 weeks) (Grade 1C recommendation) 1
• Longer courses (4-6 weeks) may be needed in a minority of patients 1

Follow-up and Further Investigation

• When to investigate further: If wet cough persists after 4 weeks of appropriate antibiotics, further investigations should be undertaken (Grade 2B recommendation) 1

• Recommended investigations:

  • Flexible bronchoscopy with quantitative cultures and sensitivities
  • Chest CT scan (especially if recurrent episodes)
  • Assessment for immunologic competency 1

• Warning signs requiring immediate investigation (specific cough pointers):

  • Digital clubbing
  • Coughing with feeding
  • Failure to thrive
  • Chest wall deformity
  • Persistent focal chest signs 1

Recurrent PBB and Risk of Bronchiectasis

• Children with chronic wet cough that does not resolve after 4 weeks of appropriate antibiotics have increased risk of bronchiectasis (adjusted OR 5.9,95% CI 1.2-28.5) 1
• Recurrent PBB (>3 episodes in 12 months) is associated with future diagnosis of bronchiectasis 2
• Research suggests longer initial treatment (6 weeks vs 2 weeks) may reduce risk of recurrent PBB 2, though this must be balanced with antimicrobial stewardship concerns

Clinical Pearls and Pitfalls

Common Pitfalls

• Misdiagnosis as asthma: PBB is often misdiagnosed as asthma, leading to inappropriate use of steroids 3
• Delayed diagnosis: Failure to recognize and treat PBB may lead to progression to chronic suppurative lung disease or bronchiectasis 3
• Overtreatment: Unnecessarily prolonged antibiotic courses contribute to antimicrobial resistance 3

Important Considerations

• A recent randomized controlled trial found that 4-week treatment did not significantly improve clinical cure rates by day 28 compared to 2-week treatment (62% vs 70%), but did lead to significantly longer time to next wet cough exacerbation (150 days vs 36 days) 4
• Flexible bronchoscopy is not warranted in all children with chronic wet cough, particularly if cough resolves with antibiotic treatment 1
• Consider local antibiotic sensitivity patterns when selecting treatment 1

Monitoring and Outcomes

Key outcomes to monitor include:

• Resolution of cough (using cough score/diary)
• Relapse of chronic wet cough
• Quality of life changes
• Emergence of antibiotic resistance
• Development of bronchiectasis
• Microbiological clearance of identified respiratory pathogens 5

By following this structured approach to the management of PBB, clinicians can effectively treat this condition while minimizing the risk of progression to more serious respiratory diseases.