Does bronchitis (inflammation of the bronchial tubes) always show up on a chest X-ray (CXR)?

Bronchitis Does Not Always Show Up on Chest X-Ray

Bronchitis often does not show up on chest X-ray, with normal findings in up to 34% of patients with significant bronchial disease. 1 Chest X-ray has limited sensitivity for detecting the bronchial wall inflammation characteristic of bronchitis.

Imaging Findings in Bronchitis

Chest X-ray (CXR) Limitations

• When bronchitis does appear on CXR, typical findings include:

  • Bronchial wall thickening
  • Peribronchial cuffing
  • Hyperinflation
  • Flattening of the diaphragm
  • Increased retrosternal airspace 1

• However, these findings are often subtle or absent, making CXR an unreliable tool for definitively diagnosing or excluding bronchitis

High-Resolution CT (HRCT) Superiority

• HRCT is considered the reference standard for evaluating bronchial disease 1
• HRCT can detect direct signs of bronchial disease with sensitivity and specificity exceeding 90% 1
• Common HRCT findings in bronchitis include:
  • Bronchial wall thickening
  • Mosaic attenuation on expiratory imaging (air trapping)
  • Peribronchial inflammation 2, 1

Clinical Implications

When to Consider Advanced Imaging

• The American College of Radiology recommends:

  • Starting with chest radiography for patients with chronic cough
  • Proceeding to CT only in specific scenarios:
    • Persistent symptoms despite optimal treatment
    • Abnormal chest radiograph
    • Presence of red flag symptoms (hemoptysis, weight loss, fever, recurrent pneumonia) 1

• Non-contrast CT is generally sufficient for evaluation of chronic cough 2, 1

Avoiding Unnecessary Radiation

• Prospective studies have shown that most patients with chronic cough can be successfully managed without CT examination 1
• In a study by Kastelik et al., 17 patients who underwent chest CT without specific clinical indications did not have findings that altered their management 2

Bronchiolitis Considerations

• In pediatric bronchiolitis, CXR findings may also be normal or nonspecific
• Studies show poor correlation between clinical severity and radiological changes in bronchiolitis 3
• One study found that CXR was positive in only 38/52 patients with clinically diagnosed bronchiolitis 4
• Current guidelines do not support routine radiography in children with bronchiolitis 5

Common Pitfalls

1. Assuming a normal CXR excludes bronchitis: A normal CXR does not rule out bronchitis, as significant bronchial disease can be present despite normal radiographic findings.

2. Overreliance on CXR: Diagnosis of bronchitis should be primarily clinical, with imaging used to exclude other conditions rather than to confirm bronchitis.

3. Unnecessary radiation exposure: Routine use of CT for bronchitis evaluation exposes patients to radiation without clear clinical benefit in most cases.

4. Confusing bronchitis with other conditions: Bronchial wall thickening on imaging can be seen in multiple conditions including asthma, COPD, and bronchiectasis, not just acute bronchitis.

In conclusion, while bronchitis may cause radiographic abnormalities on chest X-ray, these findings are often absent or nonspecific, making CXR an insensitive tool for definitively diagnosing or excluding bronchitis.