Treatment of Orbital Cellulitis
Orbital cellulitis requires immediate broad-spectrum intravenous antibiotics targeting common pathogens including Streptococcus pneumoniae, Haemophilus influenzae, Streptococcus pyogenes, Staphylococcus aureus, Moraxella species, anaerobes, and in some cases, fungal organisms like Aspergillus and zygomycetes. 1
Etiology and Diagnosis
Orbital cellulitis is an infection of tissues posterior to the orbital septum, most commonly arising as a complication of sinusitis (particularly ethmoid sinusitis). Other causes include:
Diagnosis is based on:
- Clinical presentation: eyelid edema, erythema, chemosis, proptosis, ophthalmoplegia, vision changes, fever, headache
- Imaging studies: CT or MRI of orbits and brain with contrast to identify extent of infection, presence of abscess, and potential intracranial extension 3
Treatment Algorithm
1. Initial Management
- Immediate hospitalization for all cases of orbital cellulitis
- Obtain cultures when possible (blood cultures or drainage material from subperiosteal region) 1
- Initiate broad-spectrum IV antibiotics immediately after cultures are obtained
2. Antibiotic Therapy
First-line IV Antibiotic Regimens:
Adults:
- Vancomycin (15-20 mg/kg IV every 8-12 hours) PLUS
- Third-generation cephalosporin (e.g., ceftriaxone) or ampicillin-sulbactam 4
Children:
- Similar coverage but with age-appropriate dosing
- Avoid doxycycline in children under 8 years 4
Alternative Regimens:
- For MRSA coverage: Vancomycin, linezolid, daptomycin, or ceftaroline 4
- For penicillin-allergic patients: Clindamycin (provides coverage for MRSA, streptococci, and anaerobes) 4
3. Surgical Intervention
- Indications for surgical drainage:
- Sinus drainage is necessary when orbital cellulitis is secondary to sinusitis 2
4. Transition to Oral Therapy
- Switch to oral antibiotics when significant clinical improvement occurs
- Oral regimen options:
5. Follow-up
- Reassess within 48-72 hours to ensure clinical improvement
- If no improvement, consider:
- Broadening antibiotic coverage
- Repeat surgical drainage
- Evaluation for underlying conditions 4
Special Considerations
MRSA Coverage
Consider MRSA coverage in patients with:
- Previous MRSA infection or colonization
- Injection drug use
- Systemic inflammatory response syndrome
- Failed initial antibiotic treatment
- Immunocompromised status 4
Potential Complications
- Vision loss
- Cavernous sinus thrombosis
- Meningitis
- Intracranial abscess
- Osteomyelitis 2
Emerging Evidence
Recent research suggests that in select cases, primary oral antibiotic therapy with ciprofloxacin and clindamycin may be as effective as IV therapy, particularly for less severe cases 5. However, this approach should be considered only for stable patients without signs of severe infection or complications.
Antibiotic Resistance Patterns
Antibiotic resistance is a growing concern, with studies showing high resistance rates to penicillin G (100%) and ampicillin (100%) among common orbital infection pathogens. Vancomycin and amikacin have shown excellent susceptibility profiles with no resistance reported in some studies 6.