A 3-week-old full-term infant presents with repetitive staccato cough, tachypnoea and absence of fever. Examination shows bilateral crackles and mild bilateral conjunctival congestion. Chest radiograph shows hyperinflation with diffuse infiltrates. Which is the most appropriate confirmatory test and treatment?

• A Blood culture and intravenous ampicillin with gentamicin
• B Nasopharyngeal NAAT for Chlamydia trachomatis and oral azithromycin ✓
• C Nasopharyngeal viral PCR and supportive care alone
• D Serum IgM ELISA for Chlamydia trachomatis and oral erythromycin

Explanation

The afebrile staccato cough with hyperinflation and preceding or concurrent conjunctivitis in a young infant is classic for Chlamydia trachomatis pneumonitis acquired during vaginal delivery. Diagnosis is made by NAAT on nasopharyngeal swab or aspirate, which is more sensitive than culture. Treatment is oral azithromycin for five days, preferred over the older fourteen-day erythromycin course because of shorter duration and lower association with infantile hypertrophic pyloric stenosis. Bacterial and viral workups do not fit this presentation.

Reference: Nelson Textbook of Pediatrics, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.