Orbital Cellulitis Organism-Specific Therapy 

Orbital cellulitis is a serious condition with potentially devastating visual and life-threatening complications. It can result from the following: ^{[1, 2, 3]}

• Following extension of an infection from the periorbital structures, most commonly from the paranasal sinuses
• Direct inoculation of the orbit due to trauma or surgery
• Hematogenous spread from bacteremia

The bacteria that typically cause orbital complications, such as Staphylococcus aureus, Haemophilus influenzae, Streptococcus species, and anaerobic species including Fusobacterium and Bacteroides, tend to mirror those that cause acute sinusitis. ^{[4, 5]} Understanding the prevalence and antibiotic resistance patterns of pathogens in the community is necessary for adequate treatment. Prompt recognition and early aggressive treatment are crucial in controlling the spread. ^[6]

Organism-specific therapeutic regimens for orbital cellulitis are discussed below.

Methicillin-sensitive Staphylococcus aureus (MSSA)

MSSA orbital cellulitis may be treated with the following regimens:

• Nafcillin 2 g IV q4h or
• Oxacillin 2 g IV q4h or
• Ampicillin-sulbactam 1.5-3 g IV q6h or
• Cefuroxime 1.5 g IV q8h or
• Ceftriaxone 1-2 g/day IV or
• Clindamycin 600 mg IV q8h

Methicillin-resistant S aureus (MRSA)

MRSA orbital cellulitis may be treated with the following regimens:

• Vancomycin 1 g (15 mg/kg) IV q12h or
• Daptomycin 6 mg/kg IV q24h56

Streptococcus pneumoniae

S pneumoniae orbital cellulitis may be treated with the following regimens:

• Amoxicillin-clavulanate 875 mg/125 mg (20-40 mg/kg) PO q12h or
• Cefpodoxime 200-400 mg (5 mg/kg) PO q12h or
• Cefdinir 600 mg/day (14 mg/kg/day) PO

Streptococcus pyogenes

S pyogenes orbital cellulitis may be treated with the following regimens:

• Ampicillin-sulbactam 1.5-3 g IV q6h or
• Ceftriaxone 1 g/day IV or
• Clindamycin 600 mg IV q8h

Zygomycetes or Aspergillus

Zygomycetes or Aspergillus orbital cellulitis may be treated with the following regimens:

• Voriconazole 6 mg/kg IV q12h for 2 doses, then 4 mg/kg IV q12h or
• Voriconazole 200-300 mg PO q12h or
• Amphotericin B deoxycholate 1 mg/kg IV q24h or
• Liposomal amphotericin 3-5 mg/kg q24h

Special considerations

Patients with orbital cellulitis frequently complain of fever and malaise and report a history of recent sinusitis or upper respiratory tract infection. Orbital signs include periorbital cellulitis, limitation in ocular movements, pain with ocular movements, and proptosis.

Imaging studies are crucial in defining the extent and nature of orbital involvement and determining management. CT scanning of the sinus and orbit with and without contrast is recommended.

Consider surgical drainage if the response to appropriate antibiotic therapy is poor within 48-72 hours or if CT scans show the sinuses to be completely opacified.

If the presence of a drainable fluid collection is evident on CT scan, surgical drainage should be considered.

Consider orbital surgery, with or without sinusotomy, in every case of subperiosteal or intraorbital abscess formation, leaving the drains in place for several days.

In cases of fungal infection, surgical debridement of the orbit is indicated and may necessitate exenteration of the orbit and the sinuses.

Canthotomy and cantholysis should be performed on an emergent basis if an orbital compartment syndrome is diagnosed at any point in the course of the disease.