Uveitis is defined as inflammation of the uveal tract, which is mainly composed of the iris, the ciliary body, and the choroid. Clinically, the term is now used to describe many forms of intraocular inflammation, which may not only involve the uvea but also be associated with inflammation of the surrounding structures.
The classic anatomical classification includes a) anterior uveitis, which involves the iris and ciliary body, and b) posterior uveitis, which involves the choroid and retina. Anterior uveitis is the most common form of uveitis seen in clinical practice by internists and ophthalmologists.
How do patients present to the physician?
Usual symptoms of uveitis include ocular pain, photophobia, redness of conjunctiva, visual disturbances, and excessive lacrimation. Redness from uveitis should be differentiated from that from conjunctivitis, keratitis (corneal inflammation), glaucoma, and subconjunctival hemorrhage. However, in cases of chronic indolent uveitis the eye may be white and there may be minimal symptoms. The pain is mostly a constant, dull, aching pain that is moderate to severe and that some patients refer to as a headache. A few patients may complain of floaters in front of the eyes. Referral to an ophthalmologist is always warranted in cases of uveitis.
II. Diagnostic Approach:
A. What is the differential diagnosis for this problem?
Individual forms of uveitis can be differentiated by the location of the inflammation, the duration of onset, the symmetry and distribution of inflammation, and the classic cellular deposits on the corneal endothelium, known as keratic precipitates (KPs), whose characteristics and distribution may give important clues to the type of uveitis. These precipitates are difficult to see in a naked-eye or penlight exam but can be seen clearly on a slit-lamp examination.
Uveitis can be broadly classified into four major subsets:
Uveitis associated with systemic Immune disorders (ulcerative colitis, juvenile rheumatoid arthritis, spondyloarthitides, sarcoidosis, etc.)
Infectious uveitis (CMV, toxoplasma, tuberculosis, syphilis)
Primary ocular syndrome or involvement (sympathetic ophthalmitis, bird shot choroiditis, Fuchs uveitis syndrome)
Masquerade syndrome or mimic syndrome (mostly malignancies: retinoblastoma in children and melanoma and lymphoma in adults
Uveitis can also be classified based on its location:
Anterior uveitis: involvement of iris and pars plicata
Intermediate uveitis: involvement of the posterior coliary body (pars plana)
Posterior uveitis: involvement of the choroid posterior to the vitreous base
Panuveitis: involvement of the entire uveal tract
B. Describe a diagnostic approach/method to the patient with this problem
History: Patients with anterior uveitis and intermediate uveitis usually present with red eye and diminution of vision. Although some patients might have slight ocular pain, the absence of significant ocular pain differentiates uveitis from acute angle closure glaucoma. Patients may complain of photophobia, lacrimation, redness, and decreased vision.
Circumcorneal Injection: The circumcorneal injection in acute anterior uveitis usually has a violaceous hue and a ciliary type of injection.
Keratic precipitates: Keratic precipitates are cellular deposits seen in slit-lamp examination on the endothelial lining of the cornea. Keratic precipitates are characteristic findings of acute and chronic anterior uveitis.
Aqueous flare: Aqueous flare, another slit-lamp finding, suggests inflammation of the anterior uvea as a result of leakage of proteins into the aqueous humor (the filling between the cornea and the iris) through the damaged vessels on the iris, leading to a turbid appearance of the aqueous.
Aqueous cells: Aqueous cells indicate active inflammation of the anterior uvea, leading to leakage of inflammatory cells into the aqueous humor. Aqueous cells can be observed in a careful slit-lamp exam with oblique beam.
In contrast to anterior uveitis, posterior and intermediate uveitis are diagnosed by direct visualization of active chorioretinal inflammation and/or by detecting leukocytes in the vitreous humor onophthalmic examination by panfundoscope or an indirect ophthalmoscope. Complete examination of the eye posterior to the lens usually includes a technique called scleral depression, in which the examiner looks for an inflammatory exudate over the pars plana, the portion of the eye between the retina and the ciliary body, by gentle indentation of the eyeball with the help of an indenter and visualization with an indirect ophthalmoscope. Exudates or “snowbanks” are characteristic of a relatively common form of intermediate uveitis known as pars planitis.
3. Laboratory, radiographic and other tests that are likely to be useful in diagnosing the cause of this problem.
Although there are no specific laboratory tests to diagnose uveitis (the diagnosis is based solely on clinical presentation and physical examination) certain laboratory tests can help in determining various causes of uveitis.
HLA B27 is strongly associated with ankylosing spondylitis and uveitis. HLA B27 is present in about 95 percent of patients with AS or anterior uveitis.
Positive ANA in patients with uveitis suggests the need to investigate farther for SLE and juvenile rheumatoid arthritis.
HLA B51 is associated with uveitis and Behcet disease.
Human immunodeficiency virus (HIV) testing is not routinely obtained in evaluating patients with uveitis but should be done if there are any other signs or symptoms suggesting opportunistic infections.
Sarcoidosis is often associated with idiopathic uveitis, especially in middle-aged women. It might be prudent to obtain a CT scan to rule out hilar lymphadenopathy in patients with idiopathic uveitis even when the when the chest radiograph is normal. The diagnostic value of the CT scan must be weighed against the risks from the radiation exposure from the study.
III. Management while the Diagnostic Process is Proceeding
A. Management of uveitis.
Management of uveitis is based on the cause of the disease. Most causes of infectious uveitis are treated the same way as the primary disease process (e.g., tuberculosis, CMV, HIV), and the ocular inflammation responds to the systemic treatment. The treatment for or non-infectious uveitis depends upon the location of the uveitis. The initial treatment involves local corticosteroid drops like prednisone to relieve the inflammation and mydriatic/cycloplegic medication like homatropine to relax the ciliary body and reduce the pain from ciliary spasm. These treatments will also help prevent the formation of posterior synechiae, which may interfere with the function of the pupil.
Uveitis that is primarily posterior to the lens is generally not responsive to topical medication. Options for initial treatment of intermediate or posterior uveitis include observation only and treatment with periocular injection of a long-acting glucocorticoid like triamcinolone acetate. Intraocular injection is considered riskier than periocular injection of the steroids, but this approach has also been found to be effective in treating certain forms of posterior uveitis.
Systemic treatment is reserved for resistant cases of uveitis, uveitis associated with glaucoma in which local treatment with steroid is not indicated, bilateral uveitis, and certain forms of systemic uveitis. Oral glucocorticoids, cytotoxic medications, and anti-tumor necrosis factor alpha have been used for bilateral uveitis and in those who do not respond to local steroid therapy.
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- I. Problem/Condition.
- II. Diagnostic Approach:
- A. What is the differential diagnosis for this problem?
- B. Describe a diagnostic approach/method to the patient with this problem
- 3. Laboratory, radiographic and other tests that are likely to be useful in diagnosing the cause of this problem.
- III. Management while the Diagnostic Process is Proceeding
- A. Management of uveitis.