What is the evaluation and treatment plan for a persistent cough?

Evaluation and Management of Persistent Cough

For a cough persisting since the date mentioned, begin systematic evaluation by first ruling out serious conditions with chest radiograph and vital signs, then sequentially treat the three most common causes: upper airway cough syndrome (UACS), asthma, and gastroesophageal reflux disease (GERD), which together account for approximately 90% of chronic cough cases. 1

Initial Assessment and Risk Stratification

Determine cough duration to guide management:

• Acute cough (<3 weeks): Typically viral respiratory infection; reassure that resolution expected within 3 weeks 2
• Subacute cough (3-8 weeks): Most likely post-infectious; treat with inhaled ipratropium bromide as first-line therapy 3
• Chronic cough (>8 weeks): Requires systematic evaluation for UACS, asthma, and GERD 1

Rule out life-threatening conditions immediately:

• Obtain chest radiograph to exclude pneumonia, pulmonary embolism, masses, interstitial disease, or congestive heart failure 1
• Check vital signs and perform chest examination for focal consolidation, fever >4 days, or dyspnea 2
• Assess for hemoptysis, weight loss, recurrent pneumonia, or fever—these red flags mandate chest CT scan 4

Identify medication-induced cough:

• If patient takes an ACE inhibitor, discontinue immediately and switch to another drug class 5
• ACE inhibitor cough can persist for weeks after discontinuation 6

Assess smoking status:

• Chronic bronchitis from smoking is dose-related and a leading cause of persistent cough 5
• Counsel on smoking cessation, which produces significant remission in cough symptoms 5, 1

Systematic Treatment Algorithm for Chronic Cough

Step 1: Treat Upper Airway Cough Syndrome (UACS)

Initiate empiric therapy with first-generation antihistamine-decongestant combination (e.g., brompheniramine/pseudoephedrine) 5, 1

Clinical clues suggesting UACS:

• Nasal discharge, throat clearing, postnasal drip sensation 1
• Presence of upper respiratory symptoms 1

If prominent upper airway symptoms present, add topical nasal corticosteroid 5

Allow 2-4 weeks for treatment response before proceeding to next step 1

Step 2: Evaluate and Treat Asthma

If UACS treatment fails, asthma is the next most likely cause 5

Diagnostic approach:

• Perform spirometry with bronchodilator response or bronchoprovocation challenge testing 5, 1
• Clinical clues: cough triggered by cold air, exercise, or nighttime worsening 1
• Medical history alone is unreliable for ruling in or ruling out asthma 5

Treatment:

• Initiate empiric trial of inhaled bronchodilators and/or inhaled corticosteroids if testing unavailable 1
• Consider combination therapy with inhaled corticosteroids, inhaled β-agonists, or oral leukotriene inhibitors 5
• Limited trial of oral corticosteroids may be needed before eliminating asthma from consideration 5

Important caveat: Approximately one-third of patients with acute cough are misdiagnosed with bronchitis when they actually have acute asthma; consider underlying asthma if patient has had two or more similar episodes in past 5 years 2

Step 3: Treat Gastroesophageal Reflux Disease (GERD)

If cough persists after treating UACS and asthma, initiate intensive GERD therapy 5, 1

Critical point: Reflux-associated cough may occur in the absence of gastrointestinal symptoms—failure to consider GERD is a common reason for treatment failure 5

Treatment regimen:

• High-dose proton pump inhibitor (PPI) therapy for minimum of 3 months 5, 1
• Add alginates 5
• Implement dietary modifications and lifestyle changes 1

If GERD suspected but empiric therapy fails, obtain 24-hour esophageal pH monitoring 1

Step 4: Consider Non-Asthmatic Eosinophilic Bronchitis (NAEB)

If UACS, asthma, and GERD have been eliminated or treated without resolution:

• Perform induced sputum test for eosinophils 5
• If induced sputum testing unavailable, empiric trial of corticosteroids is next step 5

Advanced Diagnostic Testing

Proceed to advanced testing if initial systematic approach fails:

• High-resolution CT (HRCT) scan to evaluate for bronchiectasis, interstitial lung disease, or occult masses 5, 1
• Bronchoscopy to evaluate for endobronchial lesions, sarcoidosis, eosinophilic bronchitis, foreign body, or occult infection 5, 1
• Consider foreign body if abrupt onset of cough 5

Management of Unexplained Chronic Cough

Unexplained chronic cough should only be diagnosed after thorough systematic evaluation and adequate therapeutic trials have failed 5

Treatment Options for Unexplained Chronic Cough:

1. Gabapentin trial (Grade 2C recommendation):

• Start at 300 mg once daily 5, 1
• Escalate as tolerated to maximum 1,800 mg daily in two divided doses 5, 1
• Discuss potential side effects and risk-benefit profile before initiating 5, 1
• Reassess risk-benefit at 6 months before continuing 5, 1
• This recommendation reflects that quality of life can be so adversely impacted that potential benefits outweigh side effects in selected patients 5

2. Multimodality speech pathology therapy (Grade 2C recommendation) 5, 1

What NOT to Do in Unexplained Chronic Cough:

• Do not prescribe inhaled corticosteroids if bronchial hyperresponsiveness and eosinophilia testing (sputum eosinophils, exhaled nitric oxide) are negative 5, 1
• Do not prescribe PPIs if objective testing for acid reflux is negative 5, 1

Critical Pitfalls to Avoid

Common errors that lead to treatment failure:

• Assuming purulent sputum indicates bacterial infection requiring antibiotics—this is typical of viral infections and does not indicate bacterial etiology 1, 2
• Inadequate treatment duration—stopping therapy before expected response time (each step requires 2-4 weeks minimum) 1
• Failing to recognize multiple simultaneous causes—more than one condition may be present, requiring combined therapy in sequential and additive steps 5, 1
• Diagnosing unexplained cough prematurely—before completing systematic evaluation and adequate therapeutic trials 5, 1
• Missing the 8-week threshold—failing to reclassify subacute cough as chronic cough, which requires different evaluation strategy 3
• Overlooking pertussis—especially if paroxysmal cough, post-tussive vomiting, or inspiratory whooping present 3
• Continuing ACE inhibitors—no patient with troublesome cough should remain on ACE inhibitors 5

Special Considerations

Therapy should be given in sequential and additive steps because more than one cause may be present 5

Referral to specialist cough clinic indicated when:

• Cough remains undiagnosed after systematic evaluation 5
• Cough persists despite optimal treatment 4
• Red flag symptoms present 4