Chest X-Ray for Chronic Cough Evaluation

Introduction to Chronic Cough Guidelines

The British Thoracic Society recommends that a chest radiograph should be undertaken in all patients with chronic cough, defined as cough lasting >8 weeks, which is echoed by the American College of Chest Physicians and American College of Radiology 1, 2, 3, 4

31% of chest X-rays ordered for persistent cough reveal abnormalities or yield a diagnosis, highlighting the importance of this diagnostic tool in evaluating chronic cough 1
Serious conditions such as lung cancer, tuberculosis, bronchiectasis, interstitial lung disease, and other treatable pulmonary pathologies must be excluded through chest X-ray 1, 2
Chest radiography is the first-line imaging test recommended by numerous pulmonary and thoracic societies before any empiric treatment trials 4

The negative predictive value of chest X-ray is only 64% for diagnosing pulmonary causes of chronic cough, indicating significant limitations in its diagnostic capability 3
Up to 34-36% of patients with normal chest X-rays have significant CT findings that are relevant to their chronic cough, suggesting the need for further imaging in some cases 3
Bronchiectasis is missed on chest X-ray in up to 34% of CT-proven cases, highlighting the potential for false negatives 5

Upper airway cough syndrome (UACS)/post-nasal drip accounts for approximately 44% of chronic cough cases, making it a common target for empiric treatment 5, 4

HRCT should be performed only after sequential empiric treatment for all three common causes has failed, or if red flags are present, such as hemoptysis, significant dyspnea, or unintentional weight loss 5, 4

If a patient is currently taking an ACE inhibitor medication, it should be discontinued immediately, as ACE inhibitors can cause chronic cough, with resolution typically occurring within days to 2 weeks (median 26 days) 5
Smoking cessation is the priority intervention for current smokers, as most patients achieve cough resolution within 4 weeks of cessation 5

In patients presenting with chronic cough and a normal chest X‑ray, the sensitivity of plain radiography for detecting subclinical pulmonary disease and early malignancy is limited, resulting in missed abnormalities that are often identified on high‑resolution CT. 6

Prospective series of individuals with chronic cough report a lung‑cancer prevalence of approximately 1–2 %; in a retrospective analysis, both patients who were ultimately diagnosed with malignancy had normal chest X‑ray findings, underscoring the need for advanced imaging despite unremarkable radiographs. 6