What is the appropriate initial workup for a patient presenting with a chronic cough?

Initial Workup for Chronic Cough

The appropriate initial workup for a patient with chronic cough should include a detailed history, physical examination, chest radiography, and spirometry. 1

Step 1: Initial Assessment

History

• Duration of cough (>8 weeks defines chronic cough)
• Character and timing of cough
• Sputum production and characteristics
• Associated symptoms (hemoptysis, weight loss, fever)
• Medication review (particularly ACE inhibitors)
• Smoking history and environmental exposures
• Occupational exposures
• Family history (including familial neuropathy)

Physical Examination

• Vital signs
• Ear, nose, and throat examination for signs of upper airway cough syndrome
• Chest examination for:
  • Crackles (coarse crackles suggest bronchiectasis, fine late inspiratory crackles suggest parenchymal lung disease)
  • Wheezing (suggests asthma or COPD)
  • Prolonged expiratory phase
• Check for finger clubbing (suggests bronchogenic carcinoma, bronchiectasis, or interstitial lung disease)
• Neurological examination of legs if family history of chronic cough (to assess for familial neuropathy)

Step 2: Initial Investigations

Mandatory Tests

• Chest radiography - should be performed in all patients with chronic cough 1

  • Helps identify obvious structural abnormalities
  • Approximately 31% of chest radiographs requested for persistent cough diagnosis are abnormal or yield a diagnosis 1

• Spirometry with bronchodilator response - should be performed in all patients with chronic cough 1

  • Helps identify airflow obstruction
  • Measure FEV1 before and after bronchodilator
  • Note: Single peak expiratory flow measurements are not recommended 1

Additional Initial Tests to Consider

• Blood eosinophil count 2
• Exhaled nitric oxide measurement 2
• Validated cough severity and quality of life instruments 2

Step 3: Management Algorithm

1. If chest radiograph is abnormal:

   • Investigate the specific abnormality appropriately
   • Do not proceed with the standard diagnostic algorithm for chronic cough

2. If spirometry shows obstruction with bronchodilator reversibility:

   • Consider asthma or COPD
   • Trial appropriate therapy

3. If normal spirometry but suspicion of cough-variant asthma or eosinophilic bronchitis:

   • Consider therapeutic trial of prednisolone 1

4. If normal initial investigations:

   • Consider empiric treatment for the most common causes:
     • Upper airway cough syndrome (trial of decongestant and first-generation antihistamine)
     • Asthma (trial of inhaled bronchodilators or corticosteroids)
     • Gastroesophageal reflux disease (empiric acid suppression therapy)
     • Nonasthmatic eosinophilic bronchitis
     • Laryngopharyngeal reflux 2, 3

Step 4: Further Investigations (if initial workup inconclusive)

• High-resolution CT (HRCT) chest - not recommended as initial investigation but should be considered when:

  • Initial workup is negative
  • Symptoms persist despite empiric treatment
  • Red flag symptoms are present (hemoptysis, weight loss, recurrent pneumonia) 1, 4
  • Suspicion of bronchiectasis, interstitial lung disease, or malignancy

• Bronchoscopy - indicated when:

  • Foreign body aspiration is suspected
  • Other more targeted investigations are normal 1

Important Caveats

• Chest CT should not be routinely performed as part of initial evaluation 1, 4

• Studies show that most patients with chronic cough can be successfully managed without CT examination 1

• The predictive value of cough characteristics (timing, character, complications) is poor for determining the cause 5

• Common causes of chronic cough in adults include:

  • Upper airway cough syndrome
  • Asthma
  • Gastroesophageal reflux disease
  • Nonasthmatic eosinophilic bronchitis
  • Chronic obstructive pulmonary disease 2, 3, 6

• Always consider medication-induced cough (particularly ACE inhibitors) and advise discontinuation if suspected 3, 7