How should I evaluate and manage a 45-year-old man with a three-month history of cough?

Evaluation and Management of a 45-Year-Old Man with 3-Month Chronic Cough

Initial Assessment

Begin with a focused history targeting ACE inhibitor use, smoking status, and red-flag symptoms, followed immediately by chest radiograph and spirometry. 1, 2

Critical Historical Elements

• Medication review: Discontinue any ACE inhibitor immediately regardless of temporal relationship—cough typically resolves within days to 2 weeks (median 26 days) 3, 4
• Smoking history: If the patient smokes, counsel on cessation as the primary intervention; most smoking-related coughs resolve within 4 weeks 3, 1
• Red-flag symptoms requiring urgent investigation include:
  • Hemoptysis 3, 1
  • Unintentional weight loss or fever 3, 2
  • Significant dyspnea at rest or night 1, 2
  • Hoarseness or dysphagia 1, 2
  • History of cancer, tuberculosis, or immunosuppression 3
• Occupational/environmental exposures to irritants or allergens 1, 4

Mandatory Baseline Investigations

• Chest radiograph to exclude malignancy, infection, structural disease, or heart failure 1, 2, 4
• Spirometry to detect obstructive airway disease 1, 5
• Cough severity quantification using validated visual analog scales or quality-of-life questionnaires 1, 2

Systematic Empiric Treatment Algorithm

The three most common causes—upper airway cough syndrome (UACS), asthma, and gastroesophageal reflux disease (GERD)—account for over 90% of chronic cough cases and should be treated sequentially. 3, 1, 2

Step 1: Treat Upper Airway Cough Syndrome (UACS) First

• UACS is the single most common cause (18.6–81.8% of cases) and should be addressed first 1, 2
• Initiate a first-generation antihistamine-decongestant combination for 1-2 weeks 2, 4
• If prominent nasal symptoms exist, add topical intranasal corticosteroids 1
• Clinical pointers include postnasal drip sensation, throat clearing, nasal discharge, or rhinorrhea 4

Step 2: Evaluate and Treat Asthma if UACS Treatment Fails

• Asthma accounts for 14.6–41.3% of chronic cough and may present with cough as the sole manifestation 1, 4
• Normal spirometry does not exclude asthma—proceed with methacholine bronchial provocation testing if spirometry is normal 1, 4
• Initiate inhaled corticosteroids with or without bronchodilators 3
• Consider a 2-week trial of oral corticosteroids (30-40 mg prednisone daily); lack of improvement suggests cough is unlikely due to eosinophilic airway inflammation 3, 1
• Response to bronchodilators may occur within 1 week, but complete resolution can take up to 8 weeks 4

Step 3: Treat GERD if Both UACS and Asthma Treatments Fail

• GERD causes 4.6–85.4% of chronic cough and frequently occurs without gastrointestinal symptoms 1, 4
• Initiate intensive acid suppression with proton pump inhibitors plus alginates for a minimum of 3 months 1, 2
• Add comprehensive dietary modifications and lifestyle changes (not just PPIs alone) 2, 4
• Be patient: response may take 2 weeks to several months, with some patients requiring 8-12 weeks 4
• Failure to consider GERD is a frequent cause of therapeutic failure 1

Step 4: Consider Nonasthmatic Eosinophilic Bronchitis (NAEB)

• NAEB accounts for 6.4–17.2% of cases and presents with normal spirometry and no airway hyperresponsiveness 1, 4
• Treat with inhaled corticosteroids 3

Critical Management Principles

• Up to 67% of patients have multiple simultaneous causes—maintain all partially effective treatments and use additive therapy 1, 2
• Schedule follow-up within 4-6 weeks to reassess response using validated cough severity measures 1, 2, 4
• Optimize therapy for each diagnosis and check compliance before abandoning a treatment approach 3

Advanced Investigation for Refractory Cases

If empiric treatments for UACS, asthma, and GERD fail after adequate trials:

• Order high-resolution CT chest to evaluate for bronchiectasis, interstitial lung disease, or occult masses 1, 4
• Consider 24-hour esophageal pH monitoring if GERD remains suspected despite empiric therapy failure 4
• Reserve bronchoscopy for suspected foreign body, endobronchial lesions, or sarcoidosis 1, 4
• Refer to a specialized cough clinic for comprehensive evaluation 1, 2

Management of Truly Refractory Chronic Cough

Only diagnose unexplained/idiopathic cough after completing systematic evaluation and adequate therapeutic trials of all common causes. 1, 4

• Consider gabapentin starting at 300 mg once daily, escalating to maximum 1,800 mg daily in divided doses 4, 5, 6
• Speech pathology/cough control therapy is a reasonable alternative 4, 5, 6
• Low-dose morphine may be considered but carries addiction risk 4, 6

Common Pitfalls to Avoid

• Never continue ACE inhibitors in any patient with troublesome chronic cough 1, 4
• Do not proceed to extensive testing before completing adequate empiric treatment trials (4-6 weeks each) 1, 2, 6
• Do not assume a single cause—sequential and additive therapy is essential given the high frequency of multiple contributing factors 1, 2
• Do not diagnose idiopathic cough prematurely before systematically addressing UACS, asthma, GERD, and NAEB 1, 4