Acute Bronchitis
A self-limiting, mostly viral inflammation of the large airways causing a persistent cough lasting 1-3 weeks.
Emergency Management: Severe respiratory distress or hemoptysis.
Acute bronchitis is a transient inflammation of the trachea and major bronchi, typically characterized by a cough that lasts for 1 to 3 weeks. It is most commonly a self-limiting viral infection that presents without clinical or radiographic evidence of pneumonia. The condition primarily affects the large conducting airways, leading to increased mucus production and bronchial hyperreactivity.
Detailed Overview
Acute bronchitis is one of the most common outpatient diagnoses, particularly during the winter months. The inflammation causes the mucous membranes of the bronchial tree to become hyperemic and edematous, diminishing mucociliary clearance. Over 90% of cases are viral in origin, making antibiotic therapy generally inappropriate and ineffective. Despite its self-limiting nature, the persistent cough can significantly impact the patient's quality of life and sleep.
Epidemiology & Demographics
Affects approximately 5% of adults annually in the US. The incidence peaks in late fall and winter. It is one of the top 10 most common illnesses for which patients seek outpatient medical care.
Etiological Mechanism
Viruses cause >90% of cases: Influenza A and B, Parainfluenza, Respiratory Syncytial Virus (RSV), Rhinovirus, Adenovirus, and Coronavirus. Bacterial causes (<10%) include Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Bordetella pertussis.
Primary Causes
Direct viral invasion of the respiratory epithelium via respiratory droplet transmission.
Infection leads to desquamation of ciliated respiratory epithelial cells and goblet cell hyperplasia. The resulting inflammatory cascade causes vasodilation, mucosal edema, and increased mucus production. Impaired mucociliary escalator function allows mucus to pool, stimulating the cough reflex. Bronchial hyperreactivity may develop and persist for weeks even after the acute infection has resolved, mimicking asthma.
Diagnostic Criteria & Guidelines
Clinical diagnosis based on acute onset of persistent cough (1-3 weeks) without clinical signs of pneumonia (e.g., normal vital signs, clear lung bases) in the absence of chronic lung disease.
Symptomatic treatment: Dextromethorphan 30 mg PO q6-8h for cough, Ibuprofen 400 mg PO q6h for pain/fever. Avoid antibiotics.
Second-Line & Adjunctive Therapy
For severe wheezing/bronchospasm: Albuterol 90 mcg/actuation MDI, 2 puffs q4-6h PRN. If influenza is confirmed < 48 hours: Oseltamivir 75 mg PO BID for 5 days.
Surgical & Procedural Management
None.
Patient Counseling & Advice
Explicitly explain that acute bronchitis is almost always viral and antibiotics will not help but may cause harm. Warn that the cough naturally lasts up to 3 weeks.
Follow-Up & Monitoring Schedule
Return to clinic if cough lasts >3 weeks, or if developing high fever, dyspnea, or hemoptysis.
Preventive Strategies
Annual influenza vaccination, frequent handwashing, avoiding sick contacts.
Excellent. Fully resolves in >95% of cases within 1-3 weeks without specific therapy.