What is the appropriate evaluation and management for a patient with a chronic cough lasting 2 months?

Evaluation and Management of 2-Month Chronic Cough

A patient with a 2-month cough requires chest radiography and spirometry as mandatory baseline investigations, followed by systematic evaluation and empiric treatment for the three most common causes: upper airway cough syndrome, asthma, and gastroesophageal reflux disease. 1

Initial Mandatory Investigations

Chest Radiography

• Obtain a chest X-ray in all patients with chronic cough (>8 weeks duration) to rule out serious pathology including malignancy, tuberculosis, bronchiectasis, and interstitial lung disease 1
• Approximately 31% of chest radiographs in patients with persistent cough will be abnormal or yield a diagnosis 1
• If the chest X-ray shows an abnormality that accounts for symptoms, investigate that finding specifically rather than proceeding with a chronic cough algorithm 1

Spirometry

• Perform spirometry in all patients with chronic cough to identify airflow obstruction and assess bronchodilator response 1
• Measure FEV1 before and after inhaling a short-acting β2-agonist (salbutamol 400 mcg by MDI with spacer or 2.5 mg by nebulizer) if obstruction is present 1
• Normal spirometry does not exclude asthma or eosinophilic bronchitis as causes of chronic cough 1

Geographic and Risk-Based Considerations

Tuberculosis Screening

• In areas with high TB prevalence, obtain sputum smears and cultures for acid-fast bacilli along with chest radiography 1
• TB should be considered but not to the exclusion of more common etiologies like upper airway cough syndrome, asthma, and gastroesophageal reflux 1
• In high-prevalence areas, chronic cough may be defined as ≥2-3 weeks duration per WHO guidelines 1

Pertussis Evaluation

• If the patient has paroxysmal coughing, post-tussive vomiting, or inspiratory whooping, obtain nasopharyngeal culture for Bordetella pertussis 1
• Pertussis can cause persistent cough; approximately 10% of chronic cough cases in some series had positive Bordetella testing 1
• If confirmed, treat with a macrolide antibiotic within the first few weeks to diminish coughing paroxysms and prevent disease spread 1

Systematic Empiric Treatment Approach

First Priority: Upper Airway Cough Syndrome (UACS)

• Trial a first-generation antihistamine plus decongestant combination for suspected upper airway cough syndrome (previously called post-nasal drip) 2, 3
• Look for symptoms of rhinitis, sinus disease, throat clearing, or sensation of postnasal drainage 4, 5
• UACS is one of the three most common causes accounting for the majority of chronic cough cases 4, 3

Second Priority: Asthma/Eosinophilic Bronchitis

• In patients with normal spirometry and bronchodilator response where cough-predominant asthma or eosinophilic bronchitis is suspected, offer a therapeutic trial of prednisolone (30-40 mg daily for 2 weeks) 1
• Alternatively, trial inhaled corticosteroids if the diagnosis is being considered 1
• Asthma may present as chronic cough without wheezing or spirometric abnormalities 1, 4

Third Priority: Gastroesophageal Reflux Disease (GERD)

• Initiate intensive acid suppression with proton pump inhibitors for a minimum of 2 months if GERD is suspected 1
• Consider GERD particularly if the patient has heartburn, regurgitation, or sour taste 2
• GERD is one of the three most common causes of chronic cough in adults 4, 3

Medication Review

• If the patient is taking an ACE inhibitor, discontinue it immediately as this is a common and reversible cause of chronic cough 4, 3
• ACE inhibitor-induced cough can persist for weeks after discontinuation 3

Red Flags Requiring Urgent Evaluation

Watch for concerning features that warrant expedited workup:

• Hemoptysis, fever, or unintentional weight loss 6
• Finger clubbing with evidence of pleural effusion or lobar collapse (suggests lung cancer) 1
• Recurrent pneumonia 6
• Smoking history with abnormal examination findings 1

When Initial Evaluation is Unrevealing

Consider CT Imaging

• High-resolution CT chest should be considered if symptoms persist despite empiric treatment of common causes 7
• CT has higher sensitivity than chest X-ray for detecting bronchiectasis, interstitial lung disease, and early malignancy 7
• The American College of Radiology recommends CT for persistent chronic cough with clinical suspicion of underlying pulmonary disease 7

Refractory Chronic Cough

• For unexplained chronic cough persisting beyond 8 weeks despite appropriate treatment, consider gabapentin or pregabalin after discussing side effects and risk-benefit profile 2, 6
• Referral to a pulmonologist or otolaryngologist may be warranted 4, 6
• Speech therapy may be beneficial for cough hypersensitivity syndrome 6

Critical Pitfalls to Avoid

• Do not prescribe antibiotics for postinfectious viral cough—they provide no benefit and contribute to antibiotic resistance 2
• Do not use long-term macrolide antibiotics for chronic cough treatment—randomized trials show they are ineffective for improving outcomes 2
• Do not assume radiographic chronic changes in elderly patients are necessarily the cause of current symptoms; they may represent age-related findings 7
• Do not rush to extensive testing before systematically addressing the three most common treatable causes (UACS, asthma, GERD) 2
• Avoid single peak flow measurements for diagnosis—they are less accurate than FEV1 for identifying airflow obstruction 1

Multiple Simultaneous Causes

• Be aware that up to 25% of patients with chronic cough have multiple contributing disorders 8
• If initial empiric treatment for one condition provides partial but incomplete relief, consider treating additional potential causes simultaneously 8, 5