How should I assess and manage a cough?

Assessment and Management of Cough

Classify cough by duration first: acute (<3 weeks), subacute (3-8 weeks), or chronic (>8 weeks), as this immediately narrows your differential diagnosis and guides your management algorithm. 1

Initial Assessment: Red Flags and Risk Factors

Screen immediately for life-threatening symptoms that require urgent evaluation 1:

• Hemoptysis
• Fever with weight loss
• Recurrent pneumonia
• Dyspnea at rest 2

Identify and eliminate high-risk factors 3:

• Discontinue ACE inhibitors (and sitagliptin) to determine if drug-induced 1, 3
• Assess smoking status and cessation 3
• Evaluate environmental and occupational exposures 1

Diagnostic Workup by Duration

Acute Cough (<3 weeks)

• Most commonly viral upper respiratory infections 4
• Address environmental/occupational triggers 1
• Use validated cough severity tools to track response 1

Subacute Cough (3-8 weeks)

The most common causes are postinfectious cough (48.4%) and upper airway cough syndrome (33.2%), followed by asthma (15.8%) 1

Initial testing 4, 5:

• Chest radiograph (first-line investigation)
• Spirometry for obstructive airway disease
• Fractional exhaled nitric oxide (FeNO) if asthma suspected 5

Follow-up within 4-6 weeks by clinic visit or telephone; arrange appointment if cough persists 1

Chronic Cough (>8 weeks)

The top five diagnoses account for approximately 90% of cases 4, 2:

1. Upper airway cough syndrome (UACS) from rhinosinus conditions
2. Asthma/cough variant asthma
3. Gastroesophageal reflux disease (GERD)
4. Nonasthmatic eosinophilic bronchitis (NAEB)
5. Combinations of the above 1

Cost-effective initial workup 4, 3:

• Chest radiograph
• Spirometry with bronchodilator
• Exhaled nitric oxide measurement
• Blood eosinophil count 3
• Validated cough severity and quality of life instruments (use routinely to assess treatment outcomes) 1

Empiric Treatment Strategy

Treat empirically for the most likely diagnosis based on history and physical examination for 4-6 weeks before pursuing extensive testing 3, 2

Specific diagnostic testing when initial evaluation is insufficient 5:

• FeNO for cough variant asthma 5
• Nasal endoscopy for UACS (optional) 5
• Paranasal sinus CT for chronic rhinosinusitis 5
• Laryngoscopy if hoarseness present 5
• Peak flow variability or bronchial challenge tests as complement to spirometry when asthma suspected 5
• GERD investigations only for patients without typical GERD symptoms 5

Important caveat: Acid suppression alone is no longer recommended for treating cough due to GERD 1

Management of Refractory Chronic Cough

When diagnostic tests and specific directed treatments fail after 4-6 weeks 3, 2:

Consider cough hypersensitivity syndrome 2

Pharmacologic options 3, 2:

• Low-dose morphine (preferred) 3
• Gabapentin 3, 2
• Pregabalin 3, 2

Non-pharmacologic intervention 3, 2:

• Speech and language therapy/cough control therapy 3, 2

Refer to specialized cough clinic for refractory unexplained chronic cough 1

Follow-Up Protocol

Routine follow-up within 4-6 weeks after initial evaluation by clinic visit or telephone 1

Arrange follow-up appointment if cough persists beyond expected resolution timeframe 1

Common Pitfalls to Avoid

• Do not routinely order sinus radiographs or chest CT without specific indications 5
• Do not use acid suppression monotherapy for GERD-related cough 1
• Do not pursue extensive diagnostic testing before completing 4-6 weeks of empiric treatment for common causes 3
• Do not forget to assess medication history, particularly ACE inhibitors and sitagliptin 1, 3