What are the diagnostic criteria for bronchitis?

Diagnostic Requirements for Bronchitis

Acute Bronchitis

Diagnose acute bronchitis only when a patient presents with acute cough (with or without sputum production) lasting no more than 3 weeks, AND you have actively excluded pneumonia, common cold, acute asthma, and COPD exacerbation. 1, 2

Required Clinical Features

• Sudden onset of cough as the predominant symptom, with or without sputum production 1, 2
• Duration of 1-3 weeks (if cough persists beyond 3 weeks, consider alternative diagnoses including postinfectious cough, asthma, or gastroesophageal reflux) 1, 2, 3
• May have preceding viral upper respiratory symptoms (rhinorrhea, sore throat) 2
• Wheezing or crackles may be present on lung auscultation 2

Mandatory Exclusion Criteria

You must rule out pneumonia by confirming the absence of ALL four of these findings: 1, 2

1. Heart rate >100 beats/min
2. Respiratory rate >24 breaths/min
3. Oral temperature >38°C (100.4°F)
4. Focal consolidation, egophony, or fremitus on chest examination

If all four findings are absent, chest radiography is not needed to exclude pneumonia. 1, 2

You must also exclude: 1, 2

• Common cold (distinguished by predominant nasal symptoms: stuffiness, discharge, sneezing, sore throat rather than lower respiratory cough)
• Acute asthma (consider this diagnosis if patient has recurrent "bronchitis" episodes—65% of patients with ≥2 episodes in 5 years actually have mild asthma) 1, 2
• COPD exacerbation (requires pre-existing COPD diagnosis)

Diagnostic Testing

Do NOT routinely order: 1, 2

• Viral cultures or serologic assays
• Sputum analyses
• Chest radiograph (unless pneumonia cannot be clinically excluded)
• Laboratory tests

The diagnosis is purely clinical based on history and physical examination. 2, 3

Critical Pitfall

One-third of patients diagnosed with acute bronchitis actually have acute asthma. 1 If a patient presents with what appears to be recurrent acute bronchitis, strongly consider asthma and perform pulmonary function testing. 2

---

Chronic Bronchitis

Diagnose chronic bronchitis when a patient has chronic cough and sputum expectoration occurring on most days for at least 3 months per year for at least 2 consecutive years, after excluding other respiratory or cardiac causes of chronic productive cough. 1, 2

Required Diagnostic Criteria

• Chronic cough and sputum production on most days 1, 2
• Duration: ≥3 months per year 1, 2
• Timeframe: ≥2 consecutive years 1, 2
• Exclusion of other causes of chronic productive cough (cardiac disease, bronchiectasis, tuberculosis, lung cancer) 1, 2

Common Risk Factors to Assess

• Cigarette, cigar, or pipe smoking 2
• Passive smoke exposure 2
• Occupational or environmental exposures 2

Major Diagnostic Pitfall

88.4% of patients with self-reported or physician-confirmed chronic bronchitis do not actually meet standard diagnostic criteria. 2 Chronic bronchitis is massively overdiagnosed—ensure patients truly meet the temporal criteria (3 months per year for 2 consecutive years) before making this diagnosis.