What are the main differential diagnoses and appropriate management for a pediatric cough in an OSCE station, considering acute (<2 weeks) versus chronic (>2 weeks) presentations and red‑flag features?

Pediatric Cough Differentials for OSCE Stations

Acute Cough (<4 weeks)

For OSCE stations, the most critical first step is distinguishing acute from chronic cough, as acute cough (<4 weeks) is typically viral and self-limiting, requiring only supportive care and parental reassurance. 1, 2

Common Acute Cough Etiologies

• Viral upper respiratory tract infection (most common): Resolves within 1-3 weeks in 90% of children, though 10% may still cough at 25 days 2, 3
• Acute bronchiolitis (infants <2 years): Presents with wheezing, tachypnea, and respiratory distress; 90% cough-free by day 21 1, 3
• Pneumonia: Look for high fever (≥39°C), tachypnea, respiratory distress, hypoxia, or rales 2, 3
• Foreign body aspiration: Sudden onset cough, unilateral wheeze, choking history 1, 2
• Pertussis: Paroxysmal cough with inspiratory whoop, post-tussive emesis 1

Red Flags Requiring Immediate Evaluation

• Coughing with feeding (suggests aspiration or swallowing dysfunction) 1, 2, 4
• Digital clubbing (indicates chronic suppurative lung disease or structural abnormality) 1, 2, 4
• Failure to thrive or poor weight gain 2, 4
• Hemoptysis 1, 2
• Respiratory distress: Respiratory rate >70/min (infants) or >50/min (older children), grunting, cyanosis, oxygen saturation <92% 4, 3
• Persistent high fever ≥39°C for ≥3 consecutive days 3

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Chronic Cough (≥4 weeks)

At 4 weeks duration, cough becomes "chronic" and requires systematic evaluation with chest radiograph and classification as wet/productive versus dry, rather than empirical treatment. 1, 2, 3

Chronic Wet/Productive Cough Differentials

• Protracted bacterial bronchitis (PBB): Most common cause of chronic wet cough; loose, rattling cough without specific pointers 1, 2, 4
• Bronchiectasis: Persistent wet cough with digital clubbing, recurrent infections 1
• Chronic suppurative lung disease: Daily productive cough, failure to thrive 1
• Cystic fibrosis: Wet cough, malabsorption, recurrent infections, family history 1
• Primary ciliary dyskinesia: Chronic wet cough, recurrent sinusitis, situs inversus 1
• Aspiration syndromes: Coughing with feeding, neurodevelopmental delay 1, 2
• Immunodeficiency: Recurrent infections, poor growth 1

Chronic Dry Cough Differentials

• Post-viral cough/bronchial hyperreactivity: Most common; follows viral infection, gradually improves 1, 5, 6
• Asthma (cough-variant): Nocturnal cough, exercise-induced, family history of atopy, responds to bronchodilators 1, 6
• Habit cough/somatic cough disorder: Loud, barking, honking quality; absent during sleep; diagnosis of exclusion after extensive evaluation 1
• Tuberculosis (high-prevalence areas): Fever, night sweats, weight loss, contact history 1
• Obstructive sleep apnea: Snoring, witnessed apneas, daytime somnolence 1
• Interstitial lung disease: Exertional dyspnea, crackles, hypoxia 1
• Cardiac causes: Exertional dyspnea, poor feeding in infants, heart murmur 1

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Systematic Approach for OSCE Stations

Step 1: Duration Classification

• <4 weeks = Acute: Supportive care unless red flags present 1, 2
• ≥4 weeks = Chronic: Requires systematic evaluation 1, 2, 3

Step 2: Identify Red Flags

• If any red flag present: Immediate investigation (chest X-ray, referral) regardless of duration 2, 4
• If no red flags: Proceed based on duration 2

Step 3: Characterize Cough Quality (for chronic cough)

• Wet/productive: Suggests airway secretions; consider PBB, bronchiectasis, aspiration 1, 2, 4
• Dry: Suggests airway irritation; consider post-viral, asthma, habit cough 1, 3

Step 4: Initial Investigations (chronic cough only)

• Chest radiograph: Mandatory for all chronic cough to exclude structural abnormalities, pneumonia, foreign body 2, 3
• Spirometry (if ≥6 years and able): Pre- and post-bronchodilator to assess for reversible obstruction 2, 3

Step 5: Management Based on Phenotype

For chronic wet cough without specific pointers:

• 2-week course of antibiotics targeting Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis (amoxicillin or amoxicillin-clavulanate) 1, 2, 4
• If resolves: Diagnosis is PBB; no further treatment needed 1, 4
• If persists after 2 weeks: Extend antibiotics for additional 2 weeks (total 4 weeks) 1, 4
• If persists after 4 weeks: Further investigations (flexible bronchoscopy, chest CT) 1

For chronic dry cough with asthma risk factors:

• Trial of inhaled corticosteroids (400 mcg/day beclomethasone equivalent) for 2-4 weeks 1
• Re-evaluate at 2-4 weeks; if no response, discontinue and investigate further 1

For non-specific chronic cough:

• Watchful waiting with re-evaluation at 2-4 weeks for emergence of specific pointers 1
• Address environmental tobacco smoke exposure 1

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Critical Management Pitfalls to Avoid

• Never use over-the-counter cough and cold medications in children <6 years; they lack efficacy and carry risk of serious adverse effects including respiratory distress 1, 3
• Never use codeine-containing medications due to potential for respiratory distress 1
• Never diagnose asthma based on cough alone without wheeze, dyspnea, or documented reversible obstruction 2, 3
• Never use empirical treatment for GERD, upper airway cough syndrome, or asthma unless specific clinical features support these diagnoses 1, 2
• Never use β-agonists or hypertonic saline for acute viral cough or post-bronchiolitis cough; they provide no benefit and have adverse effects 1, 3
• Never prescribe antibiotics for acute cough unless specific signs of bacterial infection (high fever, respiratory distress, hypoxia) are present 2, 3

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Safe Supportive Care Measures

• Honey (age >1 year): Offers more relief than placebo or diphenhydramine for acute cough 1, 3
• Adequate hydration: Helps thin secretions 2, 4, 3
• Saline nasal drops and gentle suctioning: For nasal congestion in infants 4, 3
• Elevate head of bed: Improves breathing comfort 4
• Antipyretics for fever: Acetaminophen or ibuprofen for comfort 3
• Eliminate environmental tobacco smoke exposure: Critical exacerbating factor 1, 3

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Special Considerations for High TB Prevalence Areas

• Screen for TB regardless of cough duration if patient is at risk 1
• Look for fever, night sweats, hemoptysis, weight loss, contact history 1
• Obtain chest X-ray when feasible 1
• Use XpertMTB/RIF testing when available 1

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Follow-Up Timing

• Acute cough: Re-evaluate if not improving after 48-72 hours or if deteriorating 4, 3
• Chronic cough on antibiotics: Re-evaluate at 2 weeks to assess response 1, 4
• Non-specific chronic cough: Re-evaluate at 2-4 weeks for emergence of specific pointers 1
• Any cough persisting to 4 weeks: Formal chronic cough workup with chest X-ray and systematic algorithm 1, 2, 3