What is the necessary workup for a patient with a chronic cough?

Comprehensive Workup for Chronic Cough

A detailed history, physical examination, chest radiograph, and spirometry form the cornerstone of the initial workup for chronic cough (lasting >8 weeks). 1

Initial Assessment

History Elements

• Duration of cough: Classify as acute (<3 weeks), subacute (3-8 weeks), or chronic (>8 weeks) 2
• Cough characteristics: Productive vs. non-productive, timing (nocturnal, morning), triggers
• Associated symptoms: Wheezing, dyspnea, postnasal drip, heartburn, chest pain
• Medication review: Focus on ACE inhibitors (must be discontinued regardless of temporal relationship) 1, 2
• Smoking status: Current, former, pack-years
• Occupational/environmental exposures: Irritants, allergens
• Systemic symptoms: Fever, weight loss, night sweats, hemoptysis

Physical Examination

• Focus on upper respiratory tract (sinuses, pharynx)
• Chest examination for wheezing, crackles
• Look for signs of chronic lung disease
• Check for finger clubbing (may suggest malignancy or bronchiectasis) 1

Mandatory First-Line Investigations

1. Chest radiograph: Required for all patients with chronic cough 1, 2, 3

   • If abnormal, investigate specific findings directly
   • If normal, proceed with diagnostic algorithm

2. Spirometry with bronchodilator reversibility: Mandatory for all patients 1

   • Identifies obstructive patterns (asthma, COPD)
   • Normal spirometry doesn't exclude asthma or eosinophilic bronchitis

Management Algorithm

Step 1: Address Common Modifiable Factors

• Discontinue ACE inhibitors: Regardless of temporal relationship to cough onset 1, 2
  • Resolution typically occurs within days to 2 weeks (median 26 days)
• Smoking cessation: For current smokers 1, 2
  • Majority experience cough resolution within 4 weeks

Step 2: Empiric Treatment for Common Causes

For patients with normal chest radiograph and spirometry, sequentially treat the three most common causes:

1. Upper Airway Cough Syndrome (UACS)

   • First-generation antihistamine/decongestant combination for 2-4 weeks 2
   • Add topical nasal corticosteroids if prominent upper airway symptoms 1

2. Asthma

   • Trial of inhaled corticosteroids and bronchodilators for 4 weeks 2
   • Consider short course of oral corticosteroids for severe symptoms
   • If no response, asthma is unlikely

3. Gastroesophageal Reflux Disease (GERD)

   • Intensive acid suppression with proton pump inhibitors and alginates for minimum 3 months 1, 2
   • Note: Reflux-associated cough may occur without typical GI symptoms 1

Step 3: Additional Testing for Refractory Cases

If cough persists despite empiric treatment:

1. Bronchial provocation testing: For patients with normal spirometry 1

   • Helps diagnose cough-variant asthma

2. High-resolution CT scan: Consider when other targeted investigations are normal 1

   • Not recommended as initial investigation 1
   • Particularly useful to diagnose bronchiectasis or interstitial lung disease

3. Bronchoscopy: Only if foreign body inhalation is suspected or other investigations are normal 1

Special Considerations

Red Flag Symptoms Requiring Urgent Evaluation

• Hemoptysis
• Significant weight loss
• Prominent systemic illness
• Recurrent pneumonia
• Suspicion of lung cancer 1, 3

Refractory Chronic Cough

For persistent cough despite appropriate workup and treatment:

• Consider neuromodulators (gabapentin, pregabalin) 2, 3
• Speech pathology therapy for cough suppression techniques 2
• Referral to pulmonologist or otolaryngologist 3, 4

Common Pitfalls to Avoid

• Failing to discontinue ACE inhibitors 1, 2
• Not considering GERD as a cause for cough (especially without typical GI symptoms) 1
• Inadequate duration of treatment, particularly for GERD (minimum 3 months needed) 1, 2
• Overreliance on chest CT in initial evaluation 1
• Single PEF measurements instead of proper spirometry 1

By following this systematic approach, approximately 90% of chronic cough cases can be successfully diagnosed and managed 3, 5.