What is the best management approach for a patient with a chronic cough and slightly hyperinflated lungs, possibly with a history of Chronic Obstructive Pulmonary Disease (COPD) or asthma?

Management of Chronic Cough with Slightly Hyperinflated Lungs

Begin with spirometry to confirm airflow obstruction and assess bronchodilator reversibility, then initiate smoking cessation if applicable, followed by sequential empiric treatment targeting the three most common causes: upper airway cough syndrome (UACS), asthma, and gastroesophageal reflux disease (GERD). 1

Initial Assessment and Risk Factor Modification

Obtain a chest radiograph and spirometry with bronchodilator response immediately to characterize the hyperinflation pattern and identify any underlying obstructive lung disease such as COPD or asthma. 1, 2 Hyperinflation on imaging suggests chronic airflow obstruction, which may be due to COPD, asthma, or chronic bronchitis. 1

Critical First Steps:

• If the patient smokes, smoking cessation is mandatory and nearly always effective, with cough resolution occurring within 4 weeks in most cases, though it may take longer in severe COPD. 1
• Discontinue ACE inhibitors immediately if the patient is taking one, as these are a common and reversible cause of chronic cough, with median resolution time of 26 days after discontinuation. 1, 2, 3
• Assess whether this represents stable COPD with chronic cough versus an acute exacerbation requiring antibiotics or corticosteroids. 1

Sequential Empiric Treatment Algorithm

The three most common causes of chronic cough in patients with normal or near-normal chest radiographs are UACS (most common), asthma, and GERD, accounting for the vast majority of cases. 1, 2 Chronic cough is frequently multifactorial, with patients commonly having two or even all three diagnoses simultaneously, so treatment must be sequential and additive. 1

Step 1: Treat Upper Airway Cough Syndrome First

Start with a first-generation antihistamine-decongestant combination as UACS is the most prevalent cause of chronic cough. 1, 2 Allow at least 1-2 weeks for response before moving to the next step. 2

Step 2: Evaluate and Treat for Asthma

Spirometry alone does not exclude asthma as a cause of chronic cough, as cough-variant asthma commonly presents with normal baseline spirometry. 1, 2

• Perform bronchial provocation testing (methacholine challenge) if available, as this is the gold standard for diagnosing cough-variant asthma when spirometry is normal. 1, 2
• If bronchial provocation testing is unavailable or the patient is already referred, initiate a 2-week trial of oral corticosteroids (e.g., prednisone) to diagnose eosinophilic airway inflammation. 1, 2
• If the patient responds to corticosteroids, transition to inhaled corticosteroids with or without long-acting beta-agonists for maintenance therapy. 1, 4
• Consider non-asthmatic eosinophilic bronchitis (NAEB) early in the differential, as it responds predictably to inhaled corticosteroids despite normal spirometry and negative bronchial provocation testing. 1, 2, 3

Step 3: Treat Gastroesophageal Reflux Disease

If cough persists after treating UACS and asthma/NAEB, initiate empiric treatment for GERD with intensive acid suppression therapy. 1, 2 GERD-related cough frequently occurs without typical gastrointestinal symptoms, making it easy to overlook. 2

• Allow at least 3 months of intensive acid suppression therapy before concluding GERD is not the cause, as this is a common pitfall leading to premature abandonment of effective treatment. 2

Special Considerations for Hyperinflated Lungs

COPD-Related Cough:

• In patients with confirmed COPD on spirometry, determine if the cough represents stable disease versus an acute exacerbation. 1
• For stable COPD with chronic cough, optimize bronchodilator therapy with combination inhaled corticosteroid/long-acting beta-agonist (ICS/LABA) such as fluticasone/salmeterol 250/50 mcg twice daily. 4
• Cough may persist despite optimal COPD management due to frequent exacerbations or chronic bronchitis. 1

Bronchiectasis Consideration:

• If hyperinflation is accompanied by productive cough or recurrent infections, obtain high-resolution CT chest to evaluate for bronchiectasis, which has a prevalence of approximately 4% in specialist cough clinics. 1, 2

Hypersensitivity Pneumonitis:

• If there is reduced DLCO (diffusing capacity) along with hyperinflation, consider chronic hypersensitivity pneumonitis, particularly if there is exposure to organic dusts, mold, or contaminated humidifiers. 5
• Chronic HP with bronchiolitis can present with hyperinflation and airflow limitation. 5

When Initial Treatment Fails

If sequential empiric treatment for UACS, asthma/NAEB, and GERD fails to resolve the cough after adequate trials:

• Refer to a pulmonologist or specialist cough clinic for further evaluation. 1, 2, 3
• Consider high-resolution CT chest to evaluate for bronchiectasis, interstitial lung disease, or occult structural abnormalities. 2, 5
• Bronchoscopy may be warranted if there is concern for endobronchial lesions, foreign body, or hemoptysis. 1, 3
• Only label cough as "idiopathic" or "refractory" after thorough assessment at a specialist center, as uncommon causes like tracheobronchomalacia, airway stenosis, or broncholithiasis may be missed. 2, 3

Common Pitfalls to Avoid

• Failing to recognize multifactorial cough: Treat all contributing causes simultaneously once identified, as partial treatment will not resolve symptoms. 1
• Inadequate treatment duration: GERD requires 3 months of therapy; asthma trials need at least 2 weeks. 1, 2
• Relying solely on spirometry to diagnose or exclude asthma: Normal spirometry does not rule out cough-variant asthma. 1, 2
• Overlooking environmental exposures: Assess for occupational exposures, mold, and water damage in the home environment. 2, 5