A child with retropharyngeal abscess on CT scan shows a rim-enhancing fluid collection between the posterior pharyngeal wall and the prevertebral fascia at C2–C4. The most common organism causing this condition in children under 5 years is:

• A Beta-haemolytic Streptococcus (Streptococcus pyogenes) ✓
• B Staphylococcus aureus
• C Anaerobic polymicrobial mix (Bacteroides, Fusobacterium)
• D Haemophilus influenzae type b

Explanation

In children, retropharyngeal abscesses develop from suppuration of retropharyngeal lymph nodes (nodes of Rouviere) that drain the nasopharynx, sinuses, and middle ear. The most common causative organism is Group A beta-haemolytic Streptococcus (Streptococcus pyogenes), followed by Staphylococcus aureus (including MRSA). Anaerobic polymicrobial infection is more typical of adults. Haemophilus is now rare due to vaccination.

Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.