Acute bronchitis

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.

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:

• Low-grade fever
• Wheeze

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.

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

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)