A 9-year-old boy presents with eyelid swelling, erythema, and fever of 38.5 degrees Celsius following an upper respiratory tract infection. Which single examination finding establishes the diagnosis of orbital cellulitis rather than preseptal cellulitis?
- A Proptosis with painful restriction of ocular movements ✓
- B Fever above 38 degrees Celsius
- C Tender erythematous swelling of the upper eyelid
- D Conjunctival injection
Correct answer: A. Proptosis with painful restriction of ocular movements
Explanation
Preseptal cellulitis involves tissues anterior to the orbital septum, so visual acuity, ocular motility, and globe position remain normal. Proptosis, chemosis, restricted and painful extraocular movements, or vision loss indicate spread behind the septum into the orbit. Fever, eyelid swelling, and conjunctival injection occur in both conditions, so they cannot discriminate between them.
Reference: Parsons' Diseases of the Eye, 23rd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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