What is the Chandler classification for orbital cellulitis?

Group I: inflammatory edema (periorbital/preseptal); Group II: orbital cellulitis (diffuse orbital fat inflammation); Group III: subperiosteal abscess (pus between orbital wall and periosteum); Group IV: orbital abscess (pus within orbital fat); Group V: cavernous sinus thrombosis.

What CT findings indicate subperiosteal abscess requiring drainage?

Well-defined rim-enhancing collection between orbital wall and periorbita on contrast CT; medial subperiosteal abscess in children 0.5 mL) abscesses and all abscesses in adults warrant surgical drainage.

What IV antibiotics cover orbital cellulitis?

IV ceftriaxone 2g BD + metronidazole (anaerobic cover); MRSA risk (prior abscess, contact sports): add vancomycin; continuation oral amoxicillin-clavulanate after IV course; total antibiotic duration 2-3 weeks for subperiosteal abscess.

What ophthalmological signs indicate urgent orbital decompression?

Proptosis >2 mm with ophthalmoplegia, afferent pupillary defect (optic nerve compression), visual acuity deterioration, IOP >35 mmHg, or progressive despite 48h IV antibiotics - all indicate urgent surgical drainage to prevent vision loss.

What distinguishes preseptal from postseptal orbital cellulitis?

Preseptal (periorbital): limited to anterior to orbital septum; lid edema/erythema without proptosis, normal EOM, no pain on eye movement; Postseptal (orbital): beyond orbital septum; proptosis, restricted/painful EOM, chemosis; CT distinguishes definitively; orbital is an emergency.

Orbital Cellulitis Chandler Classification and Surgical Threshold

Classifies orbital cellulitis using Chandler classification (I-V), guides CT orbital findings interpretation, indicates IV antibiotic selection, and determines subperiosteal abscess drainage criteria in pediatric/adult patients.

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