Exophthalmos

Definition

Periorbital cellulitis is an inflammation and infection of the eyelid and the skin surrounding the eye. Orbital cellulitis affects the eye socket (orbit) as well as the skin closest to it.

Description

Inside the eyelid is a septum. The septum divides the eyelid into outer and inner areas. This orbital septum helps prevent the spread of infection to the eye socket. Periorbital and orbital cellulitis are more common in children than in adults. Periorbital cellulitis, which accounts for 85-90% of all ocular cellulitis, usually occurs in children under the age of five. Responsible for the remaining 10-15% of these infections, orbital cellulitis is most common in children over the age of five.

These conditions usually begin with swelling or inflammation of one eye. Infection spreads rapidly and can cause serious problems that affect the eye or the whole body.

Causes & symptoms

Orbital and periorbital cellulitis are usually caused by infection of the sinuses near the nose. Insect bites or injuries that break the skin cause about one-third of these cellulitis infections. Orbital and periorbital cellulitis may also occur in people with a history of dental infections.

The blood of about 33 of every 100 patients with orbital or periorbital cellulitis contains bacteria known to cause:

• Acute ear infections
• Inflammation of the epiglottis (the cartilage flap that covers the opening of the windpipe during swallowing)
• Meningitis (inflammation of the membranes that enclose and protect the brain)
• Pneumonia
• Sinus infection.

People with periorbital cellulitis will have swollen, painful lids and redness, but probably no fever. About one child in five has a runny nose, and 20% have conjunctivitis. Conjunctivitis, also called pinkeye, is an inflammation of the mucous membrane that lines the eyelid and covers the front white part of the eye. It can be caused by allergy, irritation, or bacterial or viral infection.

As well as a swollen lid, other symptoms of orbital cellulitis include:

• Bulging or displacement of the eyeball (proptosis)
• Chemosis (swelling of the mucous membrane of the eyeball and eyelid as a result of infection, injury, or systemic disorders like anemia or kidney disease)
• Diminished ability to see clearly
• Eye pain
• Fever
• Paralysis of nerves that control eye movements (ophthalmoplegia).

Diagnosis

An eye doctor may use special instruments to open a swollen lid in order to:

• Examine the position of the eyeball
• Evaluate eye movement
• Test the patient's vision.

If the source of infection is not apparent, the position of the eyeball may suggest its location. Computed tomography scans (CT scans) can indicate which sinuses and bones are involved or whether abscesses have developed.

Treatment

A child who has orbital or periorbital cellulitis should be hospitalized without delay. Antibiotics are used to stop the spread of infection and prevent damage to the optic nerve, which transmits visual images to the brain.

Symptoms of optic-nerve damage or infection that has spread to sinus cavities close to the brain include:

• Very limited ability to move the eye
• Impaired response of the pupil to light and other stimulus
• Loss of visual acuity
• Papilledema (swelling of the optic disk--where the optic nerve enters the eye).

One or both eyes may be affected, and eye sockets or sinus cavities may have to be drained. These surgical procedures should be performed by an ophthalmologist or otolaryngologist.

Prognosis

If diagnosed promptly and treated with antibiotics, most orbital and periorbital cellulitis can be cured. These conditions are serious and need prompt treatment.

Infections that spread beyond the eye socket can cause:

• Abscesses in the brain or in the protective membranes that enclose it
• Bacterial meningitis
• Blood clots
• Vision loss.

Further Reading

For Your Information

Books

• Current Medical Diagnosis & Treatment 1988, edited by Lawrence M. Tierney Jr., et al. Stamford, CT: Appleton & Lange, 1998.

  Organizations

• American Academy of Ophthalmology. P.O. Box 7424, San Francisco CA. 94120-7424. (415) 561-8500. http://www.eyenet.org.
• American Optometric Association. 243 North Lindbergh Blvd., St. Louis, MO 63141. (314) 991-4100. http://www.aoanet.org.

  Other

• The Merck Manual: Periorbital and orbital cellulitis. http://www.merck.com/ (20 May 1998).

Gale Encyclopedia of Medicine. Gale Research, 1999.