Introduction

Acute bronchitis is a type of chest infection which is usually self-limiting in nature. It is a result of inflammation of the trachea and major bronchi and is therefore associated with oedematous large airways and the production of sputum. The disease course usually resolves before 3 weeks, however, 25% of patients will still have a cough beyond this time. Although there is uncertainty in the literature regarding the exact proportion of pathogens giving rise to acute bronchitis, it is accepted that viral infection is the leading cause. Around 80% of episodes occur in autumn or winter.

Epidemiology

  • Incidence: 4400.00 cases per 100,000 person-years
  • Peak incidence: 50-60 years
  • Sex ratio: 1:1
Condition Relative
incidence
Viral upper respiratory tract infections6.82
Acute bronchitis1
Pneumonia0.11
<1 1-5 6+ 16+ 30+ 40+ 50+ 60+ 70+ 80+

Clinical features

Patients typically present with an acute onset of:
  • cough: may or may not be productive
  • sore throat
  • rhinorrhoea
  • wheeze

The majority of patients with have a normal chest examination, however, some patients may present with:

Investigations

Investigations
  • acute bronchitis is typically a clinical diagnosis
  • however, if CRP testing is available this may be used to guide whether antibiotic therapy is indicated

Differential diagnosis

Differentiating acute bronchitis from pneumonia
  • History: Sputum, wheeze, breathlessness may be absent in acute bronchitis whereas at least one tends to be present in pneumonia.
  • Examination: No other focal chest signs (dullness to percussion, crepitations, bronchial breathing) in acute bronchitis other than wheeze. Moreover, systemic features (malaise, myalgia, and fever) may be absent in acute bronchitis, whereas they tend to be present in pneumonia.

Management

Management
  • analgesia
  • good fluid intake
  • consider antibiotic therapy if patients:
    • are systemically very unwell
    • have pre-existing co-morbidities
    • have a CRP of 20-100mg/L (offer delayed prescription) or a CRP >100mg/L (offer antibiotics immediately)
  • NICE Clinical Knowledge Summaries/BNF currently recommend doxycycline first-line
    • doxycycline cannot be used in children or pregnant women
    • alternatives include amoxicillin

Prognosis

The disease course usually resolves before 3 weeks, however, 25% of patients will still have a cough beyond this time.