Acute bronchitis

Acute bronchitis is a self-limiting (typically) lower respiratory tract infection. Although the name implies inflammation of the bronchi, it is also associated with inflammation of the trachea.

🏘️ Epidemiology

It is one of the most common issues in primary care. RTIs in general account for approximately 300-400 consultations per 1000.

Acute bronchitis has its highest incidence in autumn and winter (80%).

🦠 Pathophysiology and causative agents

It is mostly viral in aetiology. They are the same viral agents that cause URTIs, such as:

• Coronavirus
• Rhinovirus
• RSV
• Adenovirus

They cause acute bronchial wall inflammation which causes increased mucous production + oedema → productive cough (hallmark of LRTI). The infection often is short lasting (only several days) but the damage caused to the wall may take weeks to repair and this is why patients continue to cough for weeks.

50% of patients cough for >2 weeks while 25% of patients cough for >1 month. This is known as post-bronchitis syndrome.

⚠️ Risk factors

• Smoking
• Winter months
• Contacts with patient with RTI

😷 Presentation

Patients typically have an acute onset of:

1. Cough - it may/may not be productive with clear, white or discoloured sputum. The cough tends to last for <1 months but may can persist for >1 months in some.
2. Sore throat
3. Rhinorrhoea
4. Wheeze - not always present but may be present in some few patients, especially on forced expiration.
5. Low-grade fever - however, absence of systemic symptoms is common.

🤔

Bronchitis vs pneumonia

Sputum, wheeze and dyspnoea along with systemic features tend to be absent in acute bronchitis, while in pneumonia at least 1 is present in pneumonia.

On examination we may find dullness, crepitations, bronchial breathing in pneumonia as well.

In acute bronchitis, if crackles are present they should clear with coughing.

💯 Criteria

There is no criteria for acute bronchitis but the MacFarlane criteria may be useful for diagnosing acute bronchitis:

1. Acute illness <21 days
2. Cough as the predominant symptom.
3. >1 lower respiratory tract symptom such as sputum production, wheezing, chest pain.
4. No alternative explanation

🔍 Investigations

We can use CXR to rule out pneumonia as well if uncertain.

🧰 Management

Acute bronchitis is self-limiting and doesn’t typically require anything other than symptomatic management.

Self-care strategies should be advised such as:

• Adequate fluid intake
• Analgesic use - ibuprofen or paracetamol.

Honey, cough syrups or over-the-counter medication may also be trialled.