What is the best initial approach for a pediatric patient with a cough, mild hypo-inflation, mildly increased perihilar (perihilar) markings, and peribronchial thickening on chest X-ray?

Initial Management of Pediatric Cough with Peribronchial Thickening on Chest X-ray

This chest X-ray pattern of mild hypo-inflation with increased perihilar markings and peribronchial thickening in a child with cough is most consistent with a viral respiratory infection, and the initial approach should focus on determining cough duration and characteristics to guide management—supportive care if acute (<4 weeks), or systematic evaluation with spirometry and consideration of protracted bacterial bronchitis if chronic (≥4 weeks). 1

Immediate Assessment: Classify the Cough Duration

The single most important first step is determining whether this cough has lasted less than or more than 4 weeks, as this fundamentally changes your management approach 1:

• If cough duration is <4 weeks (acute cough): This is likely a viral upper respiratory infection, and the chest X-ray findings of peribronchial thickening with mild hypo-inflation are consistent with this diagnosis 2, 3, 4
• If cough duration is ≥4 weeks (chronic cough): This requires systematic evaluation using a pediatric-specific algorithm based on cough characteristics 1

For Acute Cough (<4 Weeks): Supportive Care Approach

The radiographic findings you describe—mild hypo-inflation with increased perihilar markings and peribronchial thickening—are classic for viral respiratory infections in children and do not require antibiotics or specific treatment initially 2, 3, 4:

Supportive Management

• Provide adequate hydration to help thin secretions 2
• Use saline nasal drops for nasal congestion relief 2
• Elevate the head of the bed to improve breathing during sleep 2
• Avoid over-the-counter cough medications in children under 6 years due to lack of efficacy and potential adverse effects 2, 5

Red Flags Requiring Immediate Escalation

Monitor for signs that would require antibiotics or further intervention 2:

• High fever ≥39°C (102.2°F) for 3+ consecutive days
• Respiratory distress (increased respiratory rate, retractions, grunting)
• Change in sputum to purulent (yellow/green) color
• No improvement or worsening after 10 days

Expected Clinical Course

• Most viral respiratory infections resolve within 1-3 weeks 2
• 10% of children may still have cough at 25 days post-infection 2
• If cough persists to 4 weeks, transition to chronic cough evaluation 1

For Chronic Cough (≥4 Weeks): Systematic Evaluation Required

At 4 weeks of cough duration, you have already completed the mandatory chest radiograph, which shows peribronchial thickening—this is an abnormal finding that requires further action 1:

Determine Cough Character (Critical Decision Point)

The next step depends entirely on whether the cough is wet/productive versus dry 1:

If Wet/Productive Cough:

• This likely represents protracted bacterial bronchitis (PBB) 1, 2, 6
• Prescribe a 2-week course of antibiotics targeting Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis 1, 2, 6
• First-line choice: Amoxicillin 45 mg/kg/day divided every 12 hours 2
• If cough persists after 2 weeks, extend antibiotics for an additional 2 weeks 2, 6

If Dry Cough:

• Perform spirometry (pre- and post-β2 agonist) if child is ≥6 years old 1
• Do NOT empirically treat for asthma unless other features of asthma are present (history of wheeze, exertional symptoms, atopy, bronchodilator reversibility on spirometry) 1
• Consider pertussis testing if paroxysmal cough with post-tussive vomiting or inspiratory "whoop" is present 1, 6

Critical Pitfalls to Avoid

Do NOT Use Empirical Treatment Approaches

The 2017 CHEST guidelines explicitly recommend against empirical treatment for upper airway cough syndrome, gastroesophageal reflux, or asthma unless specific clinical features of these conditions are present 1. This represents a major shift from adult chronic cough management.

Do NOT Diagnose Asthma Based on Cough Alone

Most children with isolated chronic cough do not have asthma, and studies show that isolated cough is not associated with airway inflammation profiles consistent with asthma 1. The older literature suggesting "cough-variant asthma" as a common diagnosis 7 has been superseded by more recent evidence showing this is uncommon in children 1.

Do NOT Ignore the Chest X-ray Findings

The peribronchial thickening you identified is an abnormal finding with infinite positive likelihood ratio for ruling in disease when present 1. While this pattern is nonspecific and can be seen in viral infections 8, 3, 4, it requires clinical correlation and may indicate underlying airway inflammation requiring treatment.

Nuances in Radiographic Interpretation

The chest X-ray findings you describe have important clinical context 3, 4:

• Peribronchial thickening with mild hypo-inflation is more commonly seen in younger children with viral infections 3, 4
• Hyperinflation (which you note is only mild in this case) is actually more typical of non-COVID viral respiratory infections than COVID-19 in young children 3
• The absence of consolidation or ground-glass opacities suggests this child likely has a milder clinical course 3, 4

Follow-Up Timeline

If treating as acute viral infection 2:

• Reassess at 10 days if no improvement
• Transition to chronic cough evaluation at 4 weeks

If treating as chronic wet cough with antibiotics 2, 6:

• Reassess after 2 weeks of antibiotics
• If improved, complete 2-4 week total course
• If not improved, refer to pediatric pulmonology

For any child with chronic cough, assess environmental tobacco smoke exposure and recommend elimination 1, as this exacerbates respiratory symptoms and impairs secretion clearance.