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Preseptal
cellulitis (periorbital cellulitis) is infection of the eyelid and
surrounding skin anterior to the orbital septum. Orbital cellulitis
(postseptal cellulitis) is infection of the orbital tissues posterior
to the orbital septum. Either can be caused by an external focus
of infection (eg, a wound), infection that extends from the nasal sinuses
or teeth, or metastatic spread from infection elsewhere. Symptoms
include eyelid pain, discoloration, and swelling; orbital cellulitis
also causes fever, malaise, proptosis, impaired ocular movement,
and impaired vision. Diagnosis is based on history, examination,
and CT or MRI. Treatment is with antibiotics and sometimes surgical
drainage.
Preseptal cellulitis and orbital cellulitis are two distinct diseases that share a few clinical symptoms and signs. Preseptal cellulitis usually begins superficial to the orbital septum. Orbital cellulitis usually begins deep to the orbital septum. Both are more common among children; preseptal cellulitis is far more common than orbital cellulitis.
Etiology
Preseptal cellulitis is caused by contiguous spread of infection from local facial or eyelid trauma, insect or animal bites, conjunctivitis, chalazion, or sinusitis.
Orbital cellulitis is most often caused by extension of infection from adjacent sinuses, especially the ethmoid sinus (75 to 90%); it is less commonly caused by direct infection accompanying local trauma (eg, insect or animal bite, penetrating eyelid injuries) or contiguous spread of infection from the face or teeth or by hematogenous spread.
Pathogens vary by etiology and age. Streptococcus pneumoniae is the most frequent pathogen associated with sinus infection, whereas Staphylococcus aureus and Streptococcus pyogenes predominate when infection arises from local trauma. Haemophilus influenzae type b, once a common cause, is now less common because of widespread vaccination. Fungi are uncommon pathogens, causing orbital cellulitis in diabetic or immunosuppressed patients. Infection in children < 9 yr is typically with a single aerobic organism; patients > 15 yr typically have polymicrobial mixed aerobic and anaerobic (Bacteroides, Peptostreptococcus) infections.
Pathophysiology
Because orbital cellulitis originates from large adjacent foci of fulminant infection (eg, sinusitis) separated by only a thin bone barrier, orbital infection can be extensive and severe. Subperiosteal fluid collections, some quite large, can accumulate; they are called subperiosteal abscesses, but many are sterile initially.
Complications include vision loss (3 to 11%) from ischemic retinopathy and optic neuropathy caused by increased intraorbital pressure; restricted ocular movements (ophthalmoplegia) caused by soft-tissue inflammation; and intracranial sequelae from central spread of infection, including cavernous sinus thrombosis, meningitis, and cerebral abscess.
Symptoms and Signs
Symptoms and signs of preseptal cellulitis include tenderness, swelling, warmth, and redness or discoloration (violaceous in the case of H. influenzae) of the eyelid. Patients may be unable to open their eyes due to swelling, but visual acuity is not affected.
Symptoms and signs of orbital cellulitis include swelling and redness of the eyelid and surrounding soft tissues, conjunctival hyperemia and chemosis, decreased ocular motility, pain with eye movements, decreased visual acuity, and proptosis caused by orbital swelling. Signs of the primary infection are also often present (eg, nasal discharge and bleeding with sinusitis, periodontal pain and swelling with abscess). Fever, malaise, and headache should raise suspicion of associated meningitis. Some or all of these findings may be absent early in the course of the infection.
Subperiosteal abscesses, if large enough, can contribute to symptoms of orbital cellulitis such as swelling and redness of the eyelid, decreased ocular motility, proptosis, and decreased visual acuity.
Diagnosis
Diagnosis is suspected clinically. Other disorders to consider include trauma, insect or animal bites without cellulitis, retained foreign bodies, allergic reactions, tumors, and inflammatory orbital pseudotumor.
Eyelid swelling may require the use of lid retractors for evaluation of the globe, and initial signs of complicated infection may be subtle. An ophthalmologist should be consulted when orbital cellulitis is suspected.
Preseptal cellulitis and orbital cellulitis are often distinguishable clinically. Preseptal cellulitis is likely if all of the following conditions occur:
If findings are equivocal, the examination is difficult (as in young children), or nasal discharge is present (suggesting sinusitis), CT or MRI should be done to confirm orbital cellulitis, exclude tumor and pseudotumor, and diagnose sinusitis if present. MRI would be better than CT if cavernous sinus thrombosis is considered.
The direction of proptosis may be a clue to the site of infection; eg, extension from the frontal sinus pushes the globe down and out, and extension from the ethmoid sinus pushes the globe laterally and out.
Blood cultures are often done (ideally before beginning antibiotics) in patients with orbital cellulitis but are positive in < 33%. Lumbar puncture is done if meningitis is suspected. Cultures of the paranasal sinus fluid are done if sinusitis is the suspected source. Other laboratory tests are not particularly helpful.
Treatment
Preseptal cellulitis
Initial therapy should be directed against sinusitis pathogens (S. pneumoniae, nontypable H. influenzae, S.
aureus, and Moraxella catarrhalis); however, in areas where methicillin-resistant S. aureus is prevalent, appropriate antibiotics should be added (eg, clindamycin, trimethoprim/sulfamethoxazole, or doxycycline for oral treatment and vancomycin for inpatient treatment). In cases with dirty wounds, gram-negative infection must be considered.
Outpatient treatment is an option for patients in whom orbital cellulitis has been definitively excluded; children should have no signs of systemic infection and should be in the care of responsible parents or guardians. Patients should be closely followed by an ophthalmologist. Outpatient treatment options include amoxicillin/clavulanate 30 mg/kg po q 8 h (for children < 12 yr) or 500 mg po tid or 875 mg po bid (for adults) for 10 days.
For inpatients, ampicillin/sulbactam 50 mg/kg IV q 6 h (for children) or 1.5 to 3 g (for adults) IV q 6 h (maximum 8 g ampicillin/day) for 7 days is an option.
Orbital cellulitis
Patients with orbital cellulitis should be hospitalized and treated with meningitis-dose antibiotics. A 2nd- or 3rd-generation cephalosporin, such as cefotaxime 50 mg/kg IV q 6 h (for children < 12 yr) or 1 to 2 g IV q 6 h (for adults) for 14 days, is an option when sinusitis is present; imipenem, ceftriaxone, and piperacillin/tazobactam are other options. If cellulitis is related to trauma or foreign body, treatment should cover gram-positive (vancomycin 1 g IV q 12 h) and gram-negative (eg, ertapenem 100 mg IV once/day) pathogens and last for 7 to 10 days or until clinically improved.
Surgery to decompress the orbit, drain an abscess, and/or open infected sinuses is indicated in any of the following circumstances:
Last full review/revision September 2008 by James Garrity, MD
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