A 6-year-old presents with sudden onset of stridor, drooling, dysphagia, and a 'tripod' position. He appears toxic with high fever. Neck X-ray shows a 'thumb sign.' Which organism is most likely responsible?
- A Staphylococcus aureus
- B Parainfluenza virus
- C Haemophilus influenzae type b ✓
- D Streptococcus pyogenes
Correct answer: C. Haemophilus influenzae type b
Explanation
The 'thumb sign' on lateral neck X-ray (enlarged, rounded epiglottis resembling a thumb) is characteristic of acute epiglottitis. Haemophilus influenzae type b was the classic causative organism before widespread Hib vaccination; it still causes cases in unimmunized children. The presentation with toxic appearance, tripod positioning, drooling, and stridor without cough is classic. Parainfluenza causes croup (steeple sign), not epiglottitis.
Reference: Ghai Essential Pediatrics, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.