eMedicine Specialties > Emergency Medicine > Ophthalmology

Iritis and Uveitis

Author: Kilbourn Gordon III, MD, FACEP, Urgent Care Physician, Primary Medical, Huntington Walk-In and Greenwich Convenient Medical Center
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Updated: Oct 1, 2007

Introduction

Background

Uveitis is defined as inflammation of one or all parts of the uveal tract. Components of the uveal tract include the iris, the ciliary body, and the choroid. Uveitis may involve all areas of the uveal tract; however, involvement most often is (1) anterior, (2) confined to the iris and the anterior chamber (iritis), or (3) confined to the iris, the anterior chamber, and the ciliary body (iridocyclitis). Posterior uveitis, also known as choroiditis and chorioretinitis, is uncommon, with the exception of cytomegalovirus (CMV) retinitis in patients with AIDS. Uveitis can be acute or chronic. The acute form is observed most commonly in the ED and is the main focus of this article.

Pathophysiology

The exact pathophysiology of uveitis is unknown. In general, uveitis is caused by an immune reaction. Uveitis often is associated with infections, such as herpes, toxoplasmosis, and syphilis; therefore, the postulated immune reaction directed against foreign molecules or antigens also may injure the uveal tract vessels and cells.

Uveitis also is found in association with autoimmune disorders, such as systemic lupus erythematosus and rheumatoid arthritis. In these cases, uveitis may be caused by a hypersensitivity reaction involving immune complex deposition within the uveal tract.

Frequency

United States

The estimated incidence is approximately 15 cases per 100,000 persons.

International

The estimated incidence is approximately 15 cases per 100,000 persons.

Mortality/Morbidity

• No deaths have been reported.
• Morbidity results from posterior synechiae formation (adhesions between the iris and the lens) that may lead to high intraocular pressure and subsequent optic nerve loss.
• Additional morbidity may include cataract formation, an adverse effect of topical steroid use.

Sex

Uveitis occurs equally in males and females.

Age

The majority of patients are aged 20-50 years.

Clinical

History

• Anterior uveitis
  • Acute - Unilateral, painful red eye, blurred vision, photophobia, and tearing
  • Chronic - Recurrent episodes, few or no acute symptoms
• Posterior uveitis
  • Blurred vision
  • Floaters
  • Occasional pain
  • Occasional photophobia

Physical

Evaluate vital signs, check visual acuity and extraocular movement, perform a funduscopic exam, measure intraocular pressure, and, most importantly, perform a slit-lamp exam.

• Findings of the examination of the lids, lashes, and lacrimal ducts are normal.
• The conjunctival exam reveals 360-degree perilimbal injection, which increases in intensity as it approaches the limbus. Differentiate this condition from conjunctivitis, in which the pattern is reversed, with the most severe inflammation at a distance from the limbus.
• Visual acuity may be decreased in the affected eye.
• Extraocular movement generally is normal.
• On the pupillary exam, the patient may have direct photophobia when the light is directed into the affected eye, as well as consensual photophobia when light is directed into the uninvolved eye.
  • Consensual photophobia is helpful in distinguishing between iritis and more superficial causes of photophobia, such as conjunctivitis. In the latter, direct, but not consensual, photophobia is noted.
  • Pupillary miosis is common.
• Slit-lamp exam
  • Examine the cornea by direct illumination with a broad beam at a 30- to 40-degree angle between the viewing microscope and the light source.
  • Examine the epithelium for abrasions, edema, ulcers, or foreign bodies.
  • Inspect the stroma for deep ulcers and edema.
  • Scan the endothelium for keratitic precipitates (white blood cells on the endothelium), a hallmark of iritis. Small to medium keratitic precipitates are classified as nongranulomatous, whereas granulomatous keratitic precipitates are large and have a greasy or "mutton-fat" granular appearance.
  • The most important structure to examine is the anterior chamber, which is bound by the cornea and the iris and is filled with aqueous humor. Examine the anterior chamber using a vertically and horizontally short beam. Normally, the aqueous humor is optically clear. In uveitis, however, an increase in the protein content of the aqueous causes an effect upon examination known as flare, which is similar to that produced by a moving projector beam in a dark smoky room.
  • White or red blood cells may be observed in the anterior chamber and are graded on a scale of 1+ to 4+.
    • 0 - None
    • 1+ - Faint (barely detectable)
    • 2+ - Moderate (clear iris and lens details)
    • 3+ - Moderate (hazy iris and lens details)
    • 4+ - Intense (fibrin deposits, coagulated aqueous)
  • White blood cells that layer in the anterior chamber are called hypopyon.
• Opacities of the lens (cataracts) may be present but are not specific for uveitis.
• Intraocular pressure may be normal or slightly decreased in the acute phase due to decreased aqueous humor production; however, pressure may become elevated as the inflammation subsides.

Causes

Although uveitis often is associated with an underlying systemic disease, approximately 50% of patients have idiopathic uveitis that is not associated with any other clinical syndrome.

• Acute nongranulomatous uveitis is associated with diseases related to human leukocyte antigen B27 (HLA B27), including ankylosing spondylitis, inflammatory bowel disease, Reiter syndrome, psoriatic arthritis, and Behçet disease. Herpes simplex, herpes zoster, Lyme disease, and trauma also are associated with acute nongranulomatous uveitis.
• Chronic nongranulomatous uveitis is associated with juvenile rheumatoid arthritis, chronic iridocyclitis of children, and Fuchs heterochromic iridocyclitis.
• Chronic granulomatous uveitis is observed with sarcoidosis, syphilis, and tuberculosis.
• Posterior uveitis is found in such diseases as toxoplasmosis, ocular histoplasmosis, syphilis, sarcoidosis, and in immunocompromised hosts with CMV or candidal or herpetic infection. Embolic retinitis also may cause posterior uveitis.

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