Cellulitis is an infection or inflammation of the eyelid skin and/or the eye socket (orbit).
The orbital septum is a fibrous membrane that separates the eyelid skin from the deeper structures of the orbit.
Preseptal cellulitis is an infection or inflammation of the eyelid skin that does not extend beyond the orbital septum into the orbit.
Orbital cellulitis is an infection or inflammation of the orbit. Since the orbit has direct communications with the sinuses, infection can spread into the orbit in a patient with a sinus infection. Orbital cellulitis is much more serious than preseseptal cellulitis.
It can be very difficult to distinguish between preseptal and orbital cellulitis, even for a doctor. In both conditions, the eyelids appear red and swollen [See figure 1]; however, in patients with preseptal cellulitis the eyes move normally and are positioned normally in the eye socket. With orbital cellulitis, there can be restriction of eye movements, and the eye might appear to be protruding more than is normal. With orbital cellulitis there is sometimes a decrease in vision and pupil reaction that is not usually seen in preseptal cellulitis.
The swelling/redness results from infection or inflammation. Causes include:
• Local spread of infection from other nearby sites
• Spread of infection from blood
• Insect bite
• Allergic reaction
A history and physical is performed. Blood may be tested for signs of infection. An imaging study (CT scan or MRI) may be obtained to evaluate for spread beyond the septum into the orbit.
Antibiotics are used if an infection is suspected. Typically antibiotics are given by mouth or by an injection, but IV medications are sometimes used. Cool compresses and antihistamines are used to treat allergy or an insect bite.
Infection can spread posteriorly into the orbit or other structures (see orbital cellulitis). Preseptal cellulitis usually responds to proper treatment and there is full recovery.
Spread of infection is the most common cause of orbital cellulitis. Causes include:
• Sinusitis (the most common cause)
• Trauma or foreign body
• Infection from the blood
• Tooth abscess
A history and physical examination is performed. Blood may be tested for infection. An imaging study (CT scan or MRI) may be obtained to evaluate for spread into and possibly beyond the orbit.
Treatment for orbital cellulitis usually involves admission to the hospital for close observation and intravenous antibiotic therapy. Consultation by an Ophthalmologist and possibly an Ear-Nose &Throat specialist are typical. Surgery to drain the orbital and sinus infection may be necessary if the condition does not improve or worsens. Patients are monitored carefully for loss of vision or evidence of pressure on the optic nerve.
Spread to surrounding tissue can cause significant worsening of the illness. Spread to the brain from the sinus and orbit may cause a brain abscess (walled off infection), meningitis (infection in tissues surrounding the brain) and/or hydrocephalus (increased pressure in the brain). These serious complications often require intense care and possibly emergency surgery. Rarely, the complications result in death; however, orbital cellulitis usually responds to proper treatment and there is generally full recovery.
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