An 8-year-old girl presents with 10 days of dry cough, low-grade fever, and malaise. Examination reveals scattered wheeze and crackles. Chest X-ray shows bilateral reticulonodular infiltrates out of proportion to her mild physical findings. Cold agglutinin titers are elevated. What is the most appropriate antibiotic?
- A Amoxicillin
- B Azithromycin ✓
- C Ceftriaxone
- D Cloxacillin
Correct answer: B. Azithromycin
Explanation
The gradual onset, prominent radiographic findings with modest examination signs, bilateral reticulonodular infiltrates, and positive cold agglutinins point to Mycoplasma pneumoniae, the commonest cause of atypical pneumonia in school-age children. Cell-wall active agents like amoxicillin and ceftriaxone are ineffective because mycoplasma lacks a cell wall, so a macrolide such as azithromycin is the drug of choice.
Reference: Nelson Textbook of Pediatrics, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.