Orbital cellulitis and preseptal cellulitis are the major infections of the ocular adnexal and orbital tissues. Orbital cellulitis is an infection of the soft tissues of the orbit posterior to the orbital septum. Preseptal cellulitis is an infection of the soft tissue of the eyelids and periocular region anterior to the orbital septum. Orbital cellulitis and preseptal cellulitis can sometimes be a continuum.
Orbital cellulitis occurs in the following 3 situations:
Streptococcus species, Staphylococcus aureus, and Haemophilus influenza type B are the most common bacterial causes of orbital cellulitis.
Pseudomonas, Klebsiella, Eikenella, and Enterococcus are less common culprits.
Polymicrobial infections with aerobic and anaerobic bacteria are more common in patients aged 16 years or older.
Fungal causes of orbital cellulitis are most commonly Aspergillus and Mucor species.
Fungi can enter the orbit. Orbital cellulitis, because of fungal infections, carries a high mortality rate in patients who are immunosuppressed.
A combination of broad-spectrum antibiotics covering for both gram positive and gram-negative organisms is required for preseptal cellulitis with the addition of anaerobic cover for orbital cellulitis.
Amphotericin is the antifungal medication of choice in the treatment of fungal orbital cellulitis. It is administered intravenously and, in cases of severe infection, may be appropriately provided before laboratory confirmation of fungal infection.
Nasal decongestants like phenylephrine and Xylometazoline may help to open the sinus ostia and aid with drainage in cases of orbital cellulitis secondary to sinusitis.
Acetazolamide can lower the intraocular pressure in orbital cellulitis.
Prednisone and prednisolone have anti-inflammatory properties and cause profound and varied metabolic effects.
Corticosteroids may be helpful, but they should not be started until after any surgery is performed and until the patient has been on appropriate antibiotics for 2-3 days.
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2. John N Harrington. Orbital Cellulitis. http://emedicine.medscape.com/article/1217858-overview
3. Patrick Watts. Preseptal and orbital cellulitis in children.Paediatrics and Child Health 2016; 26 (1), http://www.sciencedirect.com/science/article/pii/S1751722215002231.