What physical examination findings are required to diagnose bronchitis?

Physical Examination Findings for Diagnosing Acute Bronchitis

Acute bronchitis is a clinical diagnosis that requires NO specific physical examination findings to be present—instead, it is diagnosed by the presence of acute cough with or without sputum production AND the absence of findings that would indicate pneumonia or other conditions. 1

Diagnostic Approach

What Must Be Present

• Sudden onset of cough (with or without sputum expectoration) 1
• The cough is the primary presenting symptom 2

What Must Be Absent (Critical for Diagnosis)

The diagnosis of acute bronchitis is fundamentally a diagnosis of exclusion. You must rule out pneumonia, the common cold, acute asthma, and acute exacerbation of chronic bronchitis. 1

To Exclude Pneumonia, All Four of These Must Be Absent:

1. Heart rate > 100 beats/min 1
2. Respiratory rate > 24 breaths/min 1
3. Oral body temperature > 38°C 1
4. Chest examination findings of focal consolidation, egophony, or fremitus 1

If all four of these findings are absent, pneumonia is sufficiently unlikely that a chest radiograph is not needed. 1

Important Clinical Pitfalls

• Purulent (green) sputum does NOT distinguish between bacterial pneumonia and viral acute bronchitis and should not influence your diagnosis 1, 2

• No serum markers can accurately distinguish pneumonia from acute bronchitis 1

• Approximately 65% of patients with recurrent episodes of "acute bronchitis" actually have mild asthma, so consider this diagnosis in patients with repeated presentations 3

• Wheezing may be present in up to 40% of patients with acute bronchitis due to transient airflow obstruction and bronchial hyperresponsiveness, but this resolves within 6 weeks 1

Additional Diagnostic Considerations

Epidemiologic clues can support the diagnosis: 1

• Contact with confirmed pertussis cases, severe paroxysmal cough, whooping sound, or post-tussive vomiting suggests Bordetella pertussis infection
• Outbreaks in military personnel or college students may suggest Mycoplasma pneumoniae or Chlamydia pneumoniae infection

The initial clinical evaluation is crucial for longitudinal care, as many patients diagnosed with recurrent acute bronchitis may actually have underlying asthma or other chronic airway diseases (COPD, bronchiectasis) that require different management. 3