Red Eye Differential Diagnosis Part III:Uveitis: Know Your Adjectives
BY BRUCE E.
ONOFREY, RPH, OD
Uveitis is a common condition, but it is not a singular disorder that has a singular form of treatment. Rather, it is a family of disorders that has different causes, treatments and prognoses.
Location, Location, Location
The uveal tract is the middle vascular coat of the eye consisting of the iris and ciliary body anteriorly and the choroid posteriorly. Anterior uveitis generally is confined to the iris and ciliary body, whereas posterior uveitis affects the choroid. Posterior uveitis is associated with a host of serious disorders and must not be mistaken for anterior uveitis. It is characterized by posterior vitreal cells, retinal inflammation and exudates.
Tracking down the cause of uveitis helps determine your treatment plan.
Granulomatous vs Non-granulomatous
Granulomatous uveitis is traditionally associated with a host of systemic disorders, including sarcoid, syphilis and tuberculosis. In granulomatous uveitis, the underlying cause must be identified. Granulomatous uveitis includes the presence of "mutton-fat" keratitic precipitates (KP) and iris nodules consisting of clusters of white blood cells. Non-granulomatous uveitis presents with "fine" KP. This form is commonly idiopathic (no identifiable cause), or can be associated with a host of systemic disorders.
Recurrent vs Non-recurrent
Ask the patient if he has had a similar episode of uvetitis. If so, how often, how was it treated, what was the outcome and were any laboratory tests performed. Objectively, look for past episodes of iritis. Old pigmented KP on the corneal endothelium and pigment clumps on the anterior lens surface suggest old posterior synechiae; old posterior synechiae are evidence of prior episodes of anterior uveitis.
Idiopathic vs Secondary
Non-granulomatous uveitis is most commonly idiopathic (up to 80 percent). Cases that are not idiopathic are frequently associated with ankylosing spondylitis, rheu-matoid arthritis and inflammatory bowel disease (Crohn's). Secondary causes include Lyme disease, H. simplex, zoster, bacterial keratitis or trauma.
Acute vs Chronic
Acute disease tends to present dramatically with a red, painful, obviously inflamed eye. Chronic, long-standing uveitis is much more insidious. The eye may appear quiet and the patient may present with minimal complaints. However, the slit lamp exam will show the presence of significant inflammatory cells and changes which can include posterior synechiae, cataract and glaucoma.
Care involves cycloplegic therapy and steroidal anti-inflammatory treatment. Cycloplegia reduces discomfort by inhibiting ciliary spasm and iris movement. It prevents the formation of posterior synechiae, reduces inflammation by stabilizing uveal blood vessels, and prevents protein release and white blood cell migration.
The anti-inflammatory mechanism of topical steroids is well understood. They have the ability to inhibit the production of and the migration of inflammatory cells and chemical mediators. Drugs like prednisolone acetate and phosphate are the cornerstones of anti-inflammatory therapy.
Dr. Onofrey, editor and author of various oph-thlamic texts, practices in Albuquerque, NM.