A review of lab tests for uveitis: these tests can help when you need to rule out systemic etiologies of ocular inflammation.(Optometric Study Center)

Publication: Review of Optometry

Publication Date: 15-MAR-04

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Because significant ocular and/or systemic morbidity may be associated with uveitis, proper diagnosis and treatment of concomitant ocular and systemic conditions are essential. Ocular complications of unmanaged chronic inflammation may lead to cataract, glaucoma, macular edema, hypotony keratopathy, retinal detachment or phthisis. (1-5) The systemic diseases that result in uveitis--Behcet's syndrome, ulcerative colitis, histoplasmosis, sarcoidosis, syphilis, psoriasis, lupus, tuberculosis and Wegener's syndrome to name a few--can lead to significant morbidity. Left untreated, some may result in organ failure or death.

Laboratory medicine may be essential for ruling out systemic etiologies that cause repeat or chronic ocular inflammation, and for monitoring the patient's response to therapy. Here is a review of the various laboratory tests that can accomplish these goals.

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Patient Workup

The physical exam is very important in patients with uveitis. An extensive and meticulous history and review of systems is important. First, categorize the uveitis according to age, race, ethnicity and gender. Then classify it as anterior or posterior, unilateral or bilateral, and granulomatous or nongranulomatous.

The presence of granulomatous keratic precipitates is a reliable indicator of chronicity, the potential for posterior involvement and a systemic etiology. Acute (less than six weeks) vs. chronic is also an important characteristic. While granulomatous presentations are more likely to have a positive finding on initial systemic workup, rheumatoid arthritis and herpetic disease can cause nongranulomatous uveitis that can be chronic, posterior and have systemic implications.

Diagnosis is an important first step in determining the course of treatment. No workup is necessary for an initial presentation of uveitis that's nongranulomatous and unilateral, and with non-traumatic iritis--as long as it responds to treatment.

If the uveitis is bilateral, granulomatous or recurrent, or if it doesn't respond to treatment, further workup is necessary. This includes an extensive review of systems, complete blood count (CBC) with differential (table 1), fluorescent treponemal antibody absorption and rapid plasma reagent with titer. At this point, it might be prudent to confer with the patient's internist.

Review of Systems

Additional history may include questions about intravenous drug abuse, sexual promiscuity, and history of sexually transmitted diseases or blood transfusions. This can help rule out syphilis or HIV. Also consider where the patient lives and ask about any recent travel to rule out the potential for endemic infectious diseases such as Lyme, histoplasmosis or tuberculosis. A family history of collagen vascular disease is important.

A review of systems looks for other organs that may be affected and may result in secondary ophthalmic disease. Some things to look for:

* Dermatologic signs. Ask about or look for such signs as rashes, vitiligo seborrheic disease, nodules, poliosis, ulcers, nail dystrophies and alopecia. Behcet's syndrome, ulcerative colitis, histoplasmosis, sarcoidosis, syphilis, psoriasis, lupus, tuberculosis and Wegener's syndrome are some common differential diagnoses.

* Respiratory symptoms. Ask about cough, shortness of breath, hemoptysis and easy fatigue with exertion. These symptoms suggest possible tuberculosis, sarcoidosis, Wegener's syndrome or carcinoma.

* Gastrointestinal/urinary complaints. Infectious, rheumatologic or malignant diseases may present with diarrhea, abdominal pain, melena dysuria, balanitis, past or recent chancres, genital ulcerations or hematuria.

* Neurologic symptoms. These might include headache, paresthesia, confusion, tinnitus, hearing loss, personality changes or transient ischemic attacks. Lupus, multiple sclerosis, Vogt-Koyanagi-Harada syndrome (VKH), Behcet's syndrome, Lyme, herpes zoster ophthalmicus (HZO), toxoplasmosis and syphilis are potential causes. Oral ulcers may occur with Behcet's syndrome, Reiter's syndrome and ulcerative colitis. (6)

* Masquerade syndromes. Lastly, do not forget about masquerade syndromes that present as intraocular...

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