Clinical Signs of Bronchitis
The clinical signs of bronchitis depend on whether it is acute or chronic, with cough being the universal hallmark—acute bronchitis presents with cough lasting up to 6 weeks (often with mild constitutional symptoms), while chronic bronchitis is defined by productive cough and sputum expectoration occurring on most days for at least 3 months per year for 2 consecutive years. 1
Acute Bronchitis
Primary Clinical Features
- Cough lasting 1-6 weeks is the defining symptom, which may or may not be productive 1, 2
- Mild constitutional symptoms often accompany the cough 1
- Absence of pneumonia indicators: In healthy adults under 70 years, pneumonia is unlikely when ALL of the following are absent: tachycardia (heart rate >100 beats/min), tachypnea (respiratory rate >24 breaths/min), fever (oral temperature >38°C), and abnormal chest examination findings (rales, egophony, tactile fremitus) 1
Important Clinical Pitfall
Purulent sputum does NOT indicate bacterial infection—purulence results from inflammatory cells or sloughed mucosal epithelial cells and can occur with viral infections 1. This is a critical distinction, as the presence of green or yellow sputum should not trigger antibiotic prescribing 1.
Associated Features
- Symptoms often preceded by or accompanied by upper respiratory tract infection signs (sore throat, rhinorrhea) 1
- Most cases (>90%) are viral in origin 1
Chronic Bronchitis
Diagnostic Criteria
Chronic bronchitis requires cough and excessive mucus secretion with sputum production on most days during 3 consecutive months for more than 2 successive years, after excluding other respiratory or cardiac causes 1
Stable Chronic Bronchitis Features
- Chronic productive cough with mucoid to frankly purulent sputum 1
- Excessive bronchial secretions due to mucous hypersecretion 1
- May progress to airflow obstruction and COPD with emphysema 1
- Ineffective cough when airflow obstruction develops, due to decreased expiratory flow 1
Acute Exacerbation of Chronic Bronchitis
An acute exacerbation presents as sudden clinical deterioration in a stable patient with increased sputum volume, sputum purulence, and/or worsening shortness of breath, often preceded by upper respiratory tract infection symptoms 1
Key Clinical Signs During Exacerbation:
- Increased cough and sputum production 1
- Purulent sputum (change in sputum character) 1
- Worsening dyspnea 1
- Symptoms typically preceded by upper respiratory tract infection 1
Critical Differential Considerations
Clinicians must exclude other causes of respiratory deterioration including pneumonia, pulmonary embolism, heart failure, exacerbation of bronchiectasis, and pneumothorax before diagnosing acute exacerbation of chronic bronchitis 1. These conditions can mimic acute exacerbation and require different management 1.
Physical Examination Findings
Acute Bronchitis
- Normal vital signs in uncomplicated cases (absence of tachycardia, tachypnea, fever) 1
- Normal or minimally abnormal chest examination (absence of focal consolidation findings) 1
Chronic Bronchitis
- May have evidence of airflow obstruction on examination in advanced disease 1
- Signs of COPD may be present (prolonged expiratory phase, wheezing, decreased breath sounds) when disease has progressed 1
- During exacerbations, increased work of breathing may be evident 1
Clinical Context and Risk Factors
Chronic Bronchitis Risk Factors
- Cigarette smoking is the most prominent cause 1
- Atmospheric pollution and recurrent infections play contributory roles 1
- Bacterial colonization (particularly Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis) is common in stable patients, especially current smokers 1