Summary

Acute bronchitis is a self-limiting lower respiratory tract infection (RTI) characterized by inflammation of the bronchi. In more than 90% of cases, it is caused by a virus. Acute bronchitis usually follows an upper RTI and presents with cough, sometimes in combination with sputum, runny nose, chest pain, headache, and malaise. The diagnosis is made on the basis of clinical symptoms. Important differential diagnoses include bronchiolitis, a very similar disease that often leads to respiratory distress in infants, and pneumonia, which is also a serious complication of acute bronchitis. Chronic bronchitis affects the same anatomical structure but has a very different clinical picture (see COPD). Management of acute bronchitis consists of adequate hydration and possibly NSAIDs for symptomatic relief. Antibiotics are frequently and unnecessarily prescribed as part of treatment; however, they are not indicated unless the patient is at risk for secondary bacterial infection.

Etiology

Viruses (> 90% of cases)
- Influenza A and B
- Parainfluenza
- Adenovirus
- RSV
- Rhinovirus
- Coronavirus
Bacteria
- Mycoplasma pneumoniae
- Chlamydia pneumoniae
- Bordetella pertussis
- Streptococcus pneumoniae and Haemophilus influenzae (in patients with preexisting pulmonary conditions such as asthma, or as a secondary bacterial infection following viral bronchitis)
Environmental etiologies
- Pollution
- Chemicals
- Smoke

The etiology of acute bronchitis is viral in > 90% of cases!

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Clinical features

Cough
- > 5 days
- Resolves in 2–3 weeks
- Sputum (∼ 50% of cases), especially as infection progresses
Runny nose and sore throat (likely symptoms of the preceding or simultaneous URI)
Chest pain and dyspnea
Headache
Malaise
Myalgias
Fever (uncommon)

References:^[2]^[4]^[3]

Diagnostics

Acute bronchitis is a clinical diagnosis
Auscultatory findings
- Wheezing
- Rhonchi
- Coarse crackles
Further workup is indicated if pneumonia is suspected

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Differential diagnoses

See bronchiolitis
See differential diagnosis of acute cough
For cough persisting ≥ 8 weeks, see differential diagnosis of chronic cough

The differential diagnoses listed here are not exhaustive.

Treatment

Rest and adequate hydration
NSAIDs
Antibiotics: generally not recommended!
- Possible indications: patient groups with increased risk of bacterial infection; (e.g., smokers, the elderly, patients with lung disease) and patients with suspected differential diagnosis (see “Differential diagnosis” above)
Antitussives, expectorants, and bronchodilators are generally not recommended, but may be considered under specific circumstances (e.g., wheezing in older children).

References:^[4]^[3]

Complications

Respiratory failure
Secondary bacterial infections (especially pneumonia)

We list the most important complications. The selection is not exhaustive.

Prognosis

Generally self-limiting
Groups at increased risk for complications: elderly, immunocompromised patients, patients with pre-existing lung conditions