Definition and aetiology of acute bronchitis

Acute bronchitis is defined as a self-limiting lower respiratory tract infection with temporary inflammation of the airways (trachea and major bronchi) in patients without known chronic lung disease or evidence of pneumonia. Acute bronchitis causes cough and mucous production that, in most patients, lasts for up to 3 weeks. It is the most common cause of cough in patients attending general practiceKinkade, 2016National Institute for Health and Care Excellence (NICE), 2019Royal Australian College of General Practitioners (RACGP), 2016.

If a patient with chronic lung disease presents with signs of a lower respiratory tract infection, consider:

• exacerbation of asthma
• exacerbation of chronic obstructive pulmonary disease (COPD)
• exacerbation of bronchiectasis.

Common respiratory viruses (eg severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2], influenza A or B) are responsible for most cases of acute bronchitis.