(Photo contributor: Roman Shinder, MD)
*The authors acknowledge the special contributions of Douglas R. Lazzaro, MD, Amy Kulak, MD, and Wayne Scott, MD, to the prior edition.
Orbital cellulitis is an infection of the soft tissues of the orbit posterior to the orbital septum. Infection may involve any of the orbital structures, including extraocular muscles, sensory and motor nerves, and the optic nerve, and may result in abscess formation (orbital or subperiosteal abscess). Patients present with a moderate to severely inflamed, painful eye, conjunctival injection, swelling of the eyelids, and chemosis (conjunctival swelling). As infection progresses, swelling increases and the eye becomes more chemotic and proptotic. Eye movement is diminished and painful in some areas of gaze, or in severe cases, all areas of gaze (frozen globe). Patients are usually febrile and in significant pain. Orbital cellulitis most often arises as an extension of infection from the paranasal sinuses, although it may also occur as a progression of preseptal cellulitis. Causative pathogens include Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus pyogenes, and anaerobes (Peptostreptococcus, Bacteroides, Fusobacterium), depending on the source of infection and abscess formation. Differential diagnosis includes preseptal cellulitis, dacryocystitis, dacryoadenitis, intraocular or retrobulbar mass, and retrobulbar hemorrhage from trauma.
A Sagittal View of the Orbit. Sagittal view of the orbit illustrating the position of the orbital septum. The orbital septum is an extension of the orbital periosteum to the tarsal plate in both upper and lower eyelids and acts as a physical barrier, preventing spread of a preseptal infection to the orbital contents.
Orbital Cellulitis. (A, B) Unilateral eye involvement with marked swelling of both upper and lower eyelids, intense erythema, and proptosis in a highly febrile child requiring surgical drainage of a subperiosteal abscess that grew S aureus. (Photo contributor: Binita R. Shah, MD.)
Orbital Cellulitis. Severe proptosis, malalignment of globe with restriction of eye movements, swelling of eyelids, and unilateral involvement are characteristic findings of orbital cellulitis (photograph taken after drainage of subperiosteal abscess). (Photo contributor: Binita R. Shah, MD.)
Orbital Cellulitis. Left orbital cellulitis with subperiosteal abscess and extensive ethmoid and maxillary sinusitis are seen in this postcontrast CT scan. About 75% to 90% of cases of orbital cellulitis are associated with either preceding or concurrent acute paranasal sinusitis (commonly involved sinuses: ethmoid, maxillary, and frontal). (Photo contributor: John Amodio, MD.)