What is the next step in managing a patient with a persistent cough despite initial treatment?

Management of Persistent Cough Despite Initial Treatment

The next step is to systematically evaluate and treat the three most common causes—upper airway cough syndrome (UACS), asthma, and gastroesophageal reflux disease (GERD)—in sequential and additive fashion, as more than one cause is frequently present. 1, 2

Immediate Assessment Steps

First, verify that initial treatment was optimal and the patient was adherent. 1 Before proceeding further:

• Confirm the patient completed adequate treatment duration for the initially suspected cause, as premature discontinuation is a common pitfall 2
• Assess medication adherence directly, as nonadherence frequently explains treatment failure 1
• Rule out ACE inhibitor use and stop the medication if present, as this is a reversible cause 1, 2
• Obtain chest radiograph if not already done to exclude pneumonia, masses, interstitial disease, or heart failure 2

Sequential Empiric Treatment Algorithm

Step 1: Treat Upper Airway Cough Syndrome (UACS)

Initiate a first-generation antihistamine-decongestant combination as the initial empiric therapy 1, 2. Look for:

• Nasal discharge, throat clearing, or postnasal drip sensation 2
• Response typically occurs within days to weeks 1

Step 2: Evaluate and Treat Asthma

If cough persists after UACS treatment, asthma must be worked up next 1, 2:

• Perform bronchoprovocation challenge or spirometry with bronchodilator response to objectively diagnose asthma 1, 2
• Look for triggers such as cold air, exercise, or nighttime worsening 2
• If testing unavailable, initiate empiric trial of inhaled bronchodilators and/or inhaled corticosteroids 1, 2
• Note that medical history alone is unreliable for ruling asthma in or out 1

Step 3: Address Gastroesophageal Reflux Disease (GERD)

If cough persists despite treating UACS and asthma, initiate high-dose PPI therapy along with lifestyle modifications 1, 2:

• Avoid eating within 2-3 hours of bedtime, elevate head of bed, avoid trigger foods, pursue weight loss if overweight 2
• Start 4-8 week trial of once-daily PPI; escalate to twice-daily if inadequate response 2
• Be aware that up to 75% of GERD-related cough may lack typical heartburn or regurgitation symptoms 3
• Response may take several months—longer than for typical reflux symptoms 3

Step 4: Consider Nonasthmatic Eosinophilic Bronchitis (NAEB)

After eliminating or treating UACS and asthma without cough resolution, evaluate for NAEB 1:

• Perform induced sputum test for eosinophils if available 1
• If testing unavailable, initiate empiric trial of corticosteroids 1

Advanced Diagnostic Testing

If the above sequential approach fails, proceed with:

• High-resolution CT scan to evaluate for bronchiectasis, interstitial lung disease, or occult masses 2
• 24-hour esophageal pH monitoring if GERD suspected but empiric therapy failed 2
• Bronchoscopy to evaluate for endobronchial lesions, sarcoidosis, eosinophilic bronchitis, or occult infection 2

Management of Unexplained Chronic Cough

If cough remains unexplained after systematic evaluation and adequate therapeutic trials, consider gabapentin as first-line neuromodulator therapy 1, 2:

• Start at 300 mg once daily, escalating as tolerated to maximum 1,800 mg daily in two divided doses 1, 2
• Discuss potential side effects and risk-benefit profile before initiating 1
• Reassess risk-benefit at 6 months before continuing 1
• Multimodality speech pathology therapy is an alternative or complementary approach 1, 2

What NOT to Do in Unexplained Chronic Cough

• Do not prescribe inhaled corticosteroids if bronchial hyperresponsiveness and eosinophilia testing are negative 1
• Do not prescribe PPIs if objective testing for acid reflux is negative 1

Critical Pitfalls to Avoid

• Do not assume purulent sputum indicates bacterial infection requiring antibiotics 2
• Do not stop therapy before expected response time—inadequate treatment duration is a common error 2
• Recognize that multiple simultaneous causes frequently coexist, requiring combined therapy rather than sequential replacement 1, 2
• Do not diagnose unexplained cough before completing systematic evaluation and adequate therapeutic trials of all common causes 1, 2
• For postinfectious cough (3-8 weeks duration), consider inhaled ipratropium as it may attenuate symptoms; if severe and other causes ruled out, consider prednisone 30-40 mg daily for a short course 1