In a 2‑year‑old girl with acute cough, nasal congestion, fever 103 °F, conjunctivitis (sticky eyes) and a mildly elevated C‑reactive protein of 10 mg/L (normal ≤6 mg/L), is adenoviral pneumonia or Chlamydia pneumoniae infection more likely, and what is the appropriate initial management?

Adenoviral Pneumonia is More Likely in This Case

In this 2-year-old with fever, cough, conjunctivitis ("sticky eyes"), and mildly elevated CRP of 10 mg/L, adenoviral pneumonia is the most probable diagnosis, and supportive care without antibiotics is the appropriate initial management.

Clinical Features Favoring Adenovirus

The constellation of conjunctivitis with respiratory symptoms strongly suggests adenovirus rather than Chlamydia pneumoniae:

• Adenovirus characteristically causes conjunctivitis alongside respiratory infection, creating the "sticky eyes" presentation seen in this patient 1
• Chlamydia pneumoniae pneumonia in young children typically presents with prolonged cough and wheezing but not conjunctivitis 2, 3
• The acute presentation with high fever (103°F) and conjunctivitis is classic for adenoviral infection 1

CRP Pattern Supports Viral Etiology

The CRP of 10 mg/L is consistent with adenoviral infection:

• Adenovirus triggers substantial CRP elevation (median 49 mg/L, range 21-96 mg/L) that mimics bacterial infection, with 96% of pediatric adenovirus cases showing CRP >2 mg/L and 87% showing CRP >10 mg/L 1
• This immediate inflammatory response occurs independent of illness duration or severity, distinguishing it from bacterial pneumonia 1
• A CRP of 10 mg/L falls well within the expected range for viral upper respiratory infection, with peak values occurring on days 2-4 of illness 4
• CRP cannot reliably differentiate bacterial from viral pneumonia in children, as viral infections (including adenovirus) frequently produce elevated values 5

Age-Specific Considerations

At 2 years of age, this child falls into a critical diagnostic category:

• Bacterial pneumonia in children <5 years typically requires fever >38.5°C (101.3°F) PLUS chest recession PLUS respiratory rate >50/min to warrant antibiotic consideration 6
• The absence of documented tachypnea or respiratory distress in this case argues against bacterial pneumonia 2, 6
• Chlamydia pneumoniae is uncommon in children under 5 years and typically affects school-aged children 2, 7

Recommended Management Approach

Immediate Assessment

• Measure oxygen saturation and respiratory rate to determine severity 2, 6
• Assess for signs requiring hospitalization: oxygen saturation <92%, respiratory rate >70/min, difficulty breathing, grunting, or inability to feed 2, 6

Outpatient Management (if stable)

• Provide supportive care only: antipyretics for fever, ensure adequate hydration, and monitor for deterioration 6, 3
• Do not prescribe antibiotics for this presentation, as young children with mild respiratory symptoms and conjunctivitis most likely have viral infection 2, 3
• Arrange follow-up within 48 hours if not improving, or immediately if worsening 6

When to Reconsider Antibiotics

• If respiratory rate exceeds 50/min with chest recession and persistent high fever, bacterial co-infection becomes more likely 6
• If symptoms persist beyond 4 weeks with wet cough, consider protracted bacterial bronchitis requiring a 2-week antibiotic course 6
• If Mycoplasma or Chlamydia is suspected in an older child (>5 years), macrolide antibiotics would be appropriate, but this is unlikely at age 2 2, 8

Critical Pitfalls to Avoid

• Do not prescribe antibiotics based solely on elevated CRP in the presence of conjunctivitis—adenovirus produces CRP elevation that mimics bacterial infection 1
• Do not assume bacterial pneumonia without documented tachypnea and increased work of breathing 6
• CRP values between 10-60 mg/L during the first week of viral illness are common and do not indicate bacterial infection 4
• Routine chest radiography is not indicated for well-appearing children with uncomplicated respiratory infection 7