Brown syndrome (named after Dr. Harold W. Brown) is also known as Superior Oblique Tendon Sheath syndrome. It is a mechanical problem in which the superior oblique muscle/tendon (on the outside of the eyeball) does not move freely. This makes looking up and in with the affected eye difficult [See figure 1]. Brown Syndrome may be present at birth (congenital) or begin later. It may be constant or intermittent.
The eyes usually look normal except in side gaze positions. In side gaze (looking toward the affected side), one eye appears higher than the other, particularly when looking up. A vertical misalignment is sometimes noted when looking straight ahead.
Often the higher eye is mistakenly presumed to be the abnormal eye but the lower eye is affected. Brown syndrome causes the lower eye to have trouble looking upward in side gaze. Essentially the affected eye is “tethered” or held down by the tight superior oblique tendon.
Although the exact cause of Brown Syndrome is unknown, it is clear that there is an abnormality with the tendon that is part of the superior oblique muscle, the cartilage structure (trochlea) that the tendon moves through, or with the combined tendon-trochlea assembly.
These abnormalities may include a reduced elasticity of the superior oblique muscle and tendon, a thickened tendon, a short and/or tight sheath, or fibrous adhesions (scarring) of the tendon.
Hereditary cases of Brown syndrome are rare. Most cases arise without a family history (sporadic).
Acquired Brown syndrome is uncommon but may be seen following surgery, after trauma or in association with inflammatory diseases. Trauma can cause a Brown Syndrome if a blunt object hits the eye socket in the upper inside corner near the nose. Surgery for the eyelid, frontal sinus, eyeball (retinal detachment) and teeth (dental extraction) have been linked to acquired Brown syndrome. Inflammation of the tendon-trochlea complex (from adult and juvenile rheumatoid arthritis, systemic lupus erythematosus and sinusitis) can be associated with development of the problem. Sometimes the cause is never identified.
The eyes are usually straight when looking directly ahead and down. The hallmark sign of Brown syndrome is decreased ability to look upward. In some situations the eyes turn outward (exotropia) when looking up.
Brown syndrome can be associated with an abnormal head position (chin up, face turn, head tilt) for better eye cooperation. The affected eye can get “stuck” after looking up or down for long periods of time. When the eye becomes unstuck, a click is often heard and may be accompanied by pain or discomfort.
Brown syndrome may be more noticeable in children since they often look upward toward adults.
Ninety percent of patients have only one affected eye, more commonly the right.
Some children with Brown syndrome have poor binocular vision (which can result in poor depth perception), amblyopia or exotropia.
Brown syndrome can be classified according to severity. In mild cases there is a reduced ability to look up and in with the affected eye. In moderate cases, there is also a tendency for the eye to move downward as it is turned in. In severe cases there is a tendency for the affected eye to turn downward when the patient looks straight ahead.
Spontaneous resolution sometimes occurs in acquired and intermittent cases. In the congenital form of Brown syndrome, the eye movement problem is usually constant and unlikely to resolve spontaneously.
Treatment recommendations for Brown syndrome vary according to the cause and severity of the movement disorder. Close observation alone is usually sufficient in mild cases. Visual acuity and the ability to use both eyes at the same time (binocular vision) should be monitored closely in young children. Nonsurgical treatment is often advised for recently acquired, traumatic and variable cases. Systemic and locally injected corticosteroids have been used to treat inflammatory cases of acquired Brown syndrome. Nonsteroidal anti-inflammatory agents (like Ibuprofen) have also been used. Surgical treatment is usually recommended if any of the following are present: eye turns down when looking straight ahead, significant double vision, compromised bincocular vision or pronounced abnormal head position. More than one surgery may be needed for optimal management.
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