A 6-week-old afebrile infant presents with a staccato cough, tachypnea, and bilateral crackles. The child had conjunctivitis at 2 weeks of age. Chest X-ray shows diffuse interstitial infiltrates with hyperinflation. Peripheral eosinophilia is present. What is the most likely causative organism?
- A Respiratory syncytial virus
- B Chlamydia trachomatis ✓
- C Bordetella pertussis
- D Cytomegalovirus
Correct answer: B. Chlamydia trachomatis
Explanation
Chlamydia trachomatis pneumonia classically presents in afebrile infants aged 2-12 weeks with a staccato cough, tachypnea, and history of neonatal conjunctivitis. Chest X-ray shows hyperinflation with interstitial infiltrates, and eosinophilia is characteristic. RSV causes fever and wheezing. Pertussis causes paroxysmal cough with whoop. CMV is less common in immunocompetent infants.
Reference: Nelson Textbook of Pediatrics, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.