Orbital cellulitis is an infection of the fat and muscles around the eye. It affects the eyelids, eyebrows, and cheeks. It may begin suddenly or be a result of an infection that gradually becomes worse. Orbital cellulitis is different than periorbital cellulitis, which is an infection of the eyelid or skin around the eye.
Orbital cellulitis is characterized by fever, proptosis, restriction of extraocular movements, and swelling with redness of the lids.
The most common cause of orbital cellulitis is bacterial rhinosinusitis. Other potential causes include:
- Infection of the teeth, middle ear, or face
- Orbital trauma with fracture or foreign body
- Ophthalmic surgery such as strabismus surgery, blepharoplasty, radial keratotomy and retinal surgery
- Peribulbar anesthesia
- An infected mucocele that erodes into the orbit
Signs and symptoms
As a preseptal infection progresses into the orbit, the inflammatory signs typically increase with increasing redness and swelling of the eyelid with a secondary ptosis. As the infection worsens, proptosis develops and extraocular motility becomes compromised. When the optic nerve is involved, loss of visual acuity is noted and an afferent pupillary defect can be appreciated.
The intraocular pressure often increases and the orbit becomes resistant to retropulsion. The skin can feel warm to the touch and pain can be elicited with either touch or eye movements.
Examination of the nose and mouth is also warranted in order to look for any black eschar which would suggest a fungal infection. Purulent nasal discharge with hyperemic nasal mucosa may be present.
Systemic symptoms including fever and lethargy may or may not be present. Change in the appearance of the eyelids with redness and swelling is frequently a presenting symptom. Pain, particularly with eye movement, is commonly noted. Double vision may also occur.
Immediate treatment with intravenous antibiotics is necessary to prevent optic nerve damage and spread of infection to the cavernous sinuses, meninges, and brain. Infection of the paranasal sinuses is the usual underlying cause.
Infecting organisms include S pneumoniae, the incidence of which has been reduced by the administration of pneumococcal vaccine; other streptococci, such as the anginosus group; H influenzae and, less commonly, S aureus including MRSA. Penicillinase-resistant penicillin, such as nafcillin, is recommended, possibly together with metronidazole or clindamycin to treat anaerobic infections.
If trauma is the underlying cause, a cephalosporin, such as cefazolin or ceftriaxone, should be added to ensure coverage for S aureus and group A beta-hemolytic streptococci. If MRSA infection is a concern, vancomycin or clindamycin may be required.
For patients with penicillin hypersensitivity, vancomycin, levofloxacin, and metronidazole are recommended. The response to antibiotics is usually excellent, but surgery may be required to drain the paranasal sinuses or orbital abscess. In immunocompromised patients, zygomycosis must be considered.