What is the suggested assessment for postinfectious cough in adults?

Assessment of Postinfectious Cough in Adults

The assessment of postinfectious cough in adults should include screening for red flags, using validated cough severity tools, evaluating for common underlying causes, and following a structured diagnostic approach based on cough duration (3-8 weeks). 1

Definition and Classification

• Postinfectious cough is defined as cough that persists following symptoms of an acute respiratory infection for at least 3 weeks but not more than 8 weeks 1
• Cough lasting longer than 8 weeks should be reclassified as chronic cough and evaluated accordingly 1

Initial Assessment Components

History Taking - Focus on:

• Timing of cough onset in relation to respiratory infection 1
• Presence of paroxysms, post-tussive vomiting, or inspiratory whooping (suggestive of pertussis) 1
• Red flags requiring immediate evaluation: hemoptysis, significant weight loss, voice changes 1
• Environmental and occupational exposures that may exacerbate cough 1
• Medication review, particularly ACE inhibitors which can cause persistent cough 1
• Smoking history (dose-related association with persistent cough) 1

Physical Examination:

• Focus on upper and lower respiratory tract 1
• Evaluate for signs of asthma, COPD, or upper airway pathology 1

Mandatory Diagnostic Tests:

• Chest radiograph to rule out underlying lung disease 1, 2
• Spirometry to assess for airflow obstruction 1, 2
• Validated cough severity or quality of life assessment tool (e.g., Punum ladder scale) 1

Evaluation for Common Causes

Postinfectious cough can be associated with several underlying mechanisms:

1. Postviral airway inflammation - most common cause (48.4% of cases) 1, 3
2. Upper airway cough syndrome (UACS)/Postnasal drip (33.2% of cases) 1, 3
3. Cough-variant asthma (15.8% of cases) 1, 3
4. Nonasthmatic eosinophilic bronchitis (NAEB) (5.4% of cases) 1, 3

Additional Testing Based on Clinical Suspicion:

• Bronchial provocation testing for patients with normal spirometry but suspected cough-variant asthma 1, 3
• Induced sputum examination to evaluate for eosinophilic bronchitis 3
• Pertussis testing (nasopharyngeal swab for culture) when pertussis is suspected based on characteristic cough pattern 1
• High-resolution CT scan may be considered when other targeted investigations are normal 1

Special Considerations

• Pertussis should be suspected in patients with cough lasting ≥2 weeks accompanied by paroxysms of coughing, post-tussive vomiting, or inspiratory whooping sound 1
• Consider bronchoscopy only when foreign body aspiration is suspected 1
• No single test can reliably exclude corticosteroid-responsive cough 1
• Cough may persist despite normal chest radiograph in patients with pertussis or other infections 1, 3

Follow-up Assessment

• Patients should be routinely followed up within 4-6 weeks after initial evaluation 1
• If cough persists beyond 8 weeks, reclassify as chronic cough and pursue further evaluation 1, 2
• Use validated cough severity tools to objectively assess treatment response 1

Common Pitfalls to Avoid

• Failing to consider pertussis in adults with prolonged cough (often underdiagnosed) 1
• Overlooking gastroesophageal reflux as a potential contributor to persistent cough 1
• Inappropriate use of antibiotics for non-bacterial causes of postinfectious cough 1
• Neglecting to assess medication side effects, particularly ACE inhibitors 1, 2
• Inadequate follow-up of patients whose cough persists beyond the expected timeframe 1

By following this structured assessment approach, clinicians can effectively evaluate and manage postinfectious cough in adults, leading to improved outcomes and quality of life for affected patients.