Laboratory Studies
A comprehensive review of the patient's past medical history and a review of systems should guide the laboratory evaluation, and the workup should be tailored accordingly.
If a patient presents with a first episode of nongranulomatous iritis and if the medical history and the review of systems are unremarkable, laboratory studies may not be indicated. Some uveitis specialists recommend specific antitreponemal serologies on all patients with uveitis.
Iritis that is recurrent, unusual in severity, unresponsive to medical therapy, unusually persistent, or bilateral should be thoroughly evaluated.
The following list of laboratory studies may be requested. At minimum, chest radiography (see Imaging Studies) and a rapid plasma reagin (RPR) test with a specific treponemal serology, such as the fluorescent treponemal antibody absorption (FTA-ABS) test, should be ordered.
The RPR test and the FTA-ABS test, or serologic tests for syphilis, should be ordered for each patient who undergoes a laboratory evaluation for uveitis.
The erythrocyte sedimentation rate (ESR), serum lysozyme level, and angiotensin-converting enzyme (ACE) test may help in evaluating the patient for sarcoidosis. However, these are not very sensitive or specific.
HLA-B27 typing: 1% of people who are HLA-B27–positive develop acute anterior uveitis. About 55% of cases of acute anterior uveitis are associated with an HLA-B27–positive serotype, rising to about 70% in patients with recurrent episodes of acute iritis. [1]
Antinuclear antibody (ANA) and, possibly, rheumatoid factor (RF) may be indicated if juvenile idiopathic arthritis is suspected.
Lyme serologic testing should be ordered if Lyme disease is suspected (although if no history otherwise consistent with Lyme disease or exposure, the predictive positivity of a positive test is very low).
Serum creatinine and urinalysis, including urinary beta-2 microglobulin levels, should be obtained if tubulointerstitial nephritis and uveitis are suspected. Beta-2 microglobulin is a low-molecular-weight protein that forms the light chain component of class I histocompatibility(HLA: antigens. Increased urine levels are seen in proximal tubular renal damage due to a variety of causes, including cadmium, mercury, lithium, or aminoglycoside toxicity; pyelonephritis; and Balkan nephropathy, a chronic interstitial nephritis of unknown etiology.
PCR testing for COVID-19 should be ordered for adult patients with symptoms suggestive of infection by this Coronavirus or for children with suspected immune dysregulation related to multi-inflammatory syndrome.
A paracentesis for polymerase chain reaction (PCR) or culture may be considered if there is a question of other viral anterior uveitis or other infectious uveitis.
Imaging Studies
Chest radiography helps to rule out sarcoidosis and tuberculosis. However, it is not very sensitive or specific.
High-resolution chest CT scanning is more sensitive for sarcoidosis than plain radiography and should be ordered if the radiographs are negative and if sarcoidosis is highly suspected as the etiology of the ocular inflammation.
Sacroiliac, lumbar, or thoracolumbar spine radiographs may be ordered if ankylosing spondylitis is suspected.
Procedures
If a patient presents with a secluded pupil from extensive posterior synechiae, iris bombe with angle-closure glaucoma may be present. In this case, an iridotomy may be necessary.
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Fine keratic precipitates in a patient with ankylosing spondylitis–associated acute anterior uveitis.
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Small stellate keratic precipitates with fine filaments in a patient with Fuchs heterochromic iridocyclitis.
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Acute anterior uveitis with plasmoid aqueous and hypopyon in a patient with ulcerative colitis.
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Fuchs heterochromic iridocyclitis with cataract and iris heterochromia.
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Iris atrophy in a patient with herpes simplex virus–associated anterior uveitis.
