What is the most appropriate next step in managing a patient with a persistent cough and a chest radiograph that shows clear lung fields, normal cardiac size, chronic bilateral pleural thickening, an old right fifth‑rib fracture, and moderate dorsal kyphosis without any acute thoracic pathology?

Management of Persistent Cough with Normal Chest Radiograph

Proceed with empiric treatment trials for the most common causes of chronic cough—upper airway cough syndrome (UACS), cough-variant asthma, and gastroesophageal reflux disease (GERD)—since the chest radiograph shows no acute pulmonary pathology and the chronic findings (pleural thickening, old fractures) are unrelated to the current cough. 1, 2

Rationale for Clinical Management Over Advanced Imaging

Your patient's chest X-ray demonstrates only chronic, incidental findings with clear lung fields and no active disease. The bilateral pleural thickening is chronic and may represent prior asbestos exposure or other remote inflammatory processes 3, while the old rib fracture and vertebral compression fractures are clearly remote injuries. None of these findings explain an active cough.

• Initial chest radiography has fulfilled its primary role: excluding serious pulmonary pathology such as malignancy, active infection, or structural abnormalities that require immediate intervention 1, 2
• The diagnostic yield of proceeding directly to CT in this scenario is extremely low: studies show that while 36-37% of chronic cough patients with normal chest X-rays have CT abnormalities, less than 1% have major findings requiring immediate intervention 2, 4
• Clinical efficacy of empiric treatment protocols is high: standardized approaches achieve diagnosis in 82-93% of chronic cough cases without advanced imaging 1

Empiric Treatment Algorithm

The American College of Chest Physicians recommends systematically addressing the three most common causes, which account for 61-67% of chronic cough diagnoses 5:

First-Line Empiric Trials

1. Upper Airway Cough Syndrome (UACS)/Post-nasal drip: Trial of first-generation antihistamine/decongestant combination for 2-3 weeks 1

2. Cough-Variant Asthma: Consider inhaled corticosteroids ± bronchodilators, especially if there are any triggers or nocturnal symptoms 1

3. GERD: Proton pump inhibitor therapy with lifestyle modifications for 8-12 weeks (GERD-related cough may take longer to respond) 1

When to Escalate to CT Imaging

Reserve chest CT for specific clinical scenarios rather than routine use 2:

Red Flag Features Requiring CT 1, 2

• Hemoptysis
• Smoker >45 years with new or changing cough pattern
• Prominent dyspnea disproportionate to examination findings
• Unexplained weight loss or systemic symptoms
• Recurrent pneumonia
• Immunosuppression
• High-risk occupational exposures (asbestos, silica)
• Palpable supraclavicular lymphadenopathy

Failed Empiric Treatment 2

• No response to appropriate trials of treatment for UACS, asthma, and GERD
• Persistent cough after 8-12 weeks of systematic empiric therapy

Critical Limitations of Chest Radiography to Recognize

While your patient's chest X-ray is reassuring, understand its limitations:

• Chest radiography misses up to 34% of bronchiectasis cases that are visible on CT 1, 2
• Sensitivity for airway abnormalities is only 69-71% compared to CT 2, 4
• The most common CT findings in chronic cough with normal X-rays are bronchiectasis (28%) and bronchial wall thickening (21%) 1, 4

However, these limitations do not justify routine CT in all patients. The key is clinical context and response to empiric therapy 2.

Common Pitfalls to Avoid

• Do not assume the chronic pleural thickening is causing the cough: this finding is stable and chronic, not an active process 3
• Do not order CT reflexively: the yield is low without red flags or failed empiric treatment, and incidental findings (especially in older patients) may lead to unnecessary interventions 2
• Do not overlook smoking history: if this patient is a smoker >45 years, bronchoscopy may be indicated even with normal chest X-ray findings 5
• Do not give inadequate treatment trials: GERD-related cough particularly requires 8-12 weeks of therapy before declaring treatment failure 1