Should I obtain a chest X‑ray (CXR) for a patient with chronic cough and normal pulmonary function testing (PFT)?

Should You Obtain a Chest X-Ray for Chronic Cough with Normal PFTs?

Yes, obtain a chest X-ray (CXR) as part of the initial evaluation for chronic cough even when pulmonary function testing is normal, as recommended by major pulmonary societies and the American College of Radiology. 1, 2, 3

Rationale for Initial Chest Radiography

• CXR is recommended as a foundational first-line imaging study to exclude serious underlying pulmonary pathology including malignancy, infectious diseases, and structural abnormalities before proceeding with empiric treatment trials. 1, 2

• The American College of Chest Physicians and German guidelines specifically recommend chest radiography alongside pulmonary function testing as part of the initial workup for chronic cough, regardless of PFT results. 2, 3

• Normal PFTs do not exclude important radiographic findings—pulmonary function testing evaluates airflow and lung volumes but cannot detect structural lesions, masses, infiltrates, or early malignancy that may be visible on imaging. 1

Understanding the Limitations of Chest X-Ray

While CXR is recommended initially, you should understand its significant limitations:

• CXR has relatively poor sensitivity (64-79% negative predictive value) for detecting pulmonary abnormalities associated with chronic cough, particularly airway diseases. 1, 4, 5

• CXR misses up to 34% of bronchiectasis cases and has only 69-71% sensitivity for airway abnormalities when compared to CT imaging. 1

• In patients with chronic cough and normal CXR, subsequent CT scanning reveals relevant abnormalities in 15-36% of cases, most commonly bronchiectasis (12%), bronchial wall thickening (10%), and mediastinal lymphadenopathy (8.5%). 6, 4, 5

When to Proceed Directly to CT Imaging

Skip CXR and proceed directly to chest CT if any red flag features are present:

• Hemoptysis, unintentional weight loss, fever, or recurrent pneumonia 7, 2
• Heavy smoking history or high-risk occupational exposures (asbestos, silica) 1, 7
• Palpable supraclavicular lymphadenopathy or other concerning physical examination findings 7
• Immunosuppression or underlying chronic pulmonary disease 1

These features elevate concern for malignancy or serious underlying disease and warrant immediate CT evaluation rather than sequential testing. 1, 7

Algorithmic Approach After Initial CXR

If CXR is normal and no red flags exist:

1. Proceed with empiric treatment trials for common causes (upper airway cough syndrome, cough-variant asthma, gastroesophageal reflux disease) based on clinical probability. 1, 2, 3

2. Reserve CT chest for patients who fail empiric treatment or when clinical suspicion exists for underlying pulmonary disease despite normal radiography. 1

3. The American College of Radiology guidelines indicate that chest CT performed without specific clinical indication in chronic cough patients yields non-contributory findings in the majority of cases. 1

Common Pitfalls to Avoid

• Do not rely on normal CXR alone to definitively exclude pulmonary causes of chronic cough, especially airway abnormalities and early interstitial disease. 1, 4

• Do not order CT routinely for all chronic cough patients with normal CXR—recent data shows that while 37% have abnormal CT findings, less than 1% have major findings (malignancy or infectious disease) requiring immediate intervention. 8

• Be aware that in elderly patients (>70 years), up to 20% may have incidental bronchiectasis on CT that is subclinical and unrelated to their cough symptoms. 1

• If the patient is taking an ACE inhibitor, consider a trial of discontinuation before extensive imaging workup. 3