What is the appropriate workup for an 11-year-old patient with a persistent cough for one month?

Workup of Persistent Cough in an 11-Year-Old

For an 11-year-old with one month of persistent cough, obtain a chest radiograph and spirometry (pre- and post-bronchodilator), then use a systematic pediatric-specific algorithm based on whether the cough is wet/productive versus dry to guide further evaluation and treatment. 1

Initial Assessment and Classification

At one month duration, this cough meets the definition of chronic cough in children (≥4 weeks) and requires systematic evaluation rather than watchful waiting. 1

Key History Elements to Determine

Cough characteristics:

• Wet/productive versus dry cough - this fundamentally determines your diagnostic pathway 1, 2
• Paroxysmal pattern with post-tussive vomiting or inspiratory "whoop" suggests pertussis even in vaccinated children 2, 3
• Timing and triggers (exercise, cold air, nighttime, talking) 1

Specific "cough pointers" indicating serious underlying disease:

• Coughing with feeding 1, 2
• Digital clubbing 1, 2
• Chest deformity 2
• Growth failure or failure to thrive 1, 2
• Hemoptysis 1

Environmental factors:

• Tobacco smoke exposure (must be identified and eliminated) 1, 2
• Known pertussis contact 2, 3

Mandatory Initial Testing

All children with chronic cough require: 1

• Chest radiograph (Grade 1B recommendation) 1, 3
• Spirometry with pre- and post-β2 agonist testing - an 11-year-old can reliably perform this test 1, 3

Diagnostic Algorithm Based on Cough Type

If Wet/Productive Cough Without Specific Pointers

Prescribe a 2-week course of antibiotics targeting common respiratory bacteria (Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis) - this treats protracted bacterial bronchitis, the most common cause. 1, 2, 3

• First-line choice: amoxicillin or amoxicillin-clavulanate 4, 2
• If cough persists after initial 2-week course, prescribe an additional 2-week course 3
• If cough persists beyond 4 weeks total of appropriate antibiotic therapy, refer to pediatric pulmonology for flexible bronchoscopy with quantitative cultures and consider chest CT 2

If Dry Cough

Do NOT empirically treat for asthma, upper airway cough syndrome, or gastroesophageal reflux disease unless other specific features consistent with these conditions are present (Grade 1A recommendation). 1, 2

For suspected asthma (history of wheeze, exertional symptoms, atopy):

• Consider testing for airway hyperresponsiveness in children >6 years if asthma is clinically suspected (Grade 2C recommendation) 1, 2
• Only initiate asthma therapy if other evidence of asthma exists beyond isolated cough 1, 4

Additional Testing Based on Clinical Suspicion

Test for Bordetella pertussis when: 1, 3

• Paroxysmal cough with post-tussive vomiting present 2, 3
• Inspiratory "whoop" noted 2, 3
• Known pertussis contact 3
• At one month duration, serology for pertussis antibodies is most appropriate (PCR if <3 weeks, serology if >3 weeks) 3

Do NOT routinely perform (Grade 1B recommendation): 1

• Skin prick testing
• Mantoux testing
• Bronchoscopy
• Chest CT
• These should only be undertaken based on specific clinical findings or if initial workup suggests underlying disease 1

Critical Pitfalls to Avoid

The empirical "shotgun" approach used in adults does not apply to children. The adult approach of empirically treating for upper airway cough syndrome, asthma, and GERD simultaneously is explicitly contraindicated in pediatrics unless specific features of these conditions are present. 1, 2 This prevents inappropriate medication use, adverse effects, and delays in identifying the true cause. 1

Cough alone does not diagnose asthma. Cough sensitivity and specificity for wheeze is poor, and chronic cough is not associated with airway inflammation profiles suggestive of asthma in most children. 2 Most children with isolated chronic cough do not have asthma. 2

Impact Assessment

Assess the effect of cough on the child and family as part of the clinical consultation, as chronic cough significantly impairs quality of life and may lead to multiple physician visits and inappropriate medication use. 1, 2

When to Refer

If a complete workup and appropriate therapeutic trials fail to identify the cause or resolve the cough, referral to a pediatric pulmonologist or cough specialist is indicated. 1, 2