Treatment of Orbital Cellulitis in Adults
For adult patients with orbital cellulitis, intravenous broad-spectrum antibiotics with coverage for both aerobic and anaerobic organisms should be initiated promptly, with vancomycin plus either piperacillin-tazobactam or a carbapenem as the recommended empiric regimen. 1
Clinical Presentation and Diagnosis
Orbital cellulitis is characterized by:
- Eyelid edema and erythema
- Chemosis (conjunctival swelling)
- Proptosis (forward displacement of the eye)
- Restricted or painful eye movements
- Vision changes
- Systemic symptoms (fever, headache)
Diagnosis requires:
- CT scan of orbits and sinuses with contrast (primary imaging modality)
- MRI if CT is non-diagnostic or intracranial extension is suspected 2
- Blood cultures (though yield is low) 3
- Cultures from abscess or infected sinuses (highest yield: 50-100%) 3
Treatment Algorithm
Initial Assessment
- Evaluate for orbital compartment syndrome (severe pain, decreased visual acuity, afferent pupillary defect)
- Assess for signs of systemic toxicity or intracranial extension
Antibiotic Therapy
Severe infection (with systemic signs, vision changes, or neurological symptoms):
Moderate infection (without severe systemic signs):
- Ampicillin-sulbactam (3 g IV every 6 hours) OR
- Ceftriaxone (1-2 g IV daily) plus metronidazole (500 mg IV every 8 hours) 1
Surgical Intervention
Immediate surgical consultation for:
- Orbital abscess
- Subperiosteal abscess
- Deteriorating vision despite antibiotics
- No improvement after 24-48 hours of IV antibiotics
- Evidence of intracranial extension 3, 2
Duration of Therapy
- Minimum 5 days of IV antibiotics
- Continue until significant clinical improvement occurs
- Switch to oral antibiotics when improving (total duration typically 2-3 weeks) 1
Adjunctive Therapy
- Elevate head of bed to reduce orbital edema 1
- Consider systemic corticosteroids in non-diabetic patients (prednisone 40 mg daily for 7 days) to reduce inflammation 1
- Treat underlying sinusitis, which is the most common predisposing cause 3, 4
Special Considerations
Microbiology
Most common pathogens:
- Streptococcus species
- Staphylococcus aureus (including MRSA)
- Anaerobes (when sinus disease is present)
- Mixed infections 3, 4
Oral Therapy Option
In selected stable patients, oral ciprofloxacin plus clindamycin may be considered as an alternative to IV therapy, as these medications have similar bioavailability to their IV counterparts 5. However, this approach should be reserved for patients without:
- Severe systemic symptoms
- Visual compromise
- Evidence of abscess formation
- Immunocompromise
Complications to Monitor
Follow-up
- Daily ophthalmologic assessment while hospitalized
- Repeat imaging if clinical deterioration occurs
- Outpatient follow-up within 1 week of discharge
Orbital cellulitis is a serious infection with potential for significant morbidity and mortality. Prompt recognition, appropriate antibiotic therapy, and timely surgical intervention when indicated are essential to prevent vision loss and life-threatening complications.