• Tips for Diagnosing Infectious Uveitis and Retinitis

    During the Spotlight on Common Approaches to Ophthalmic Urgencies session at AAO 2018, Purnima S. Patel, MD, urged clinicians to consider infectious causes for patients presenting with uveitis. She noted that identifying cases in which steroids are contraindicated is key, and she offered some tips on arriving at an accurate diagnosis.

    When should you suspect infectious etiologies? Dr. Patel noted that infectious causes should be considered in all cases of uveitis. “Think about it, at least,” said Dr. Patel. “It may not make sense, but think about it so you don’t miss it.”

    Start with a thorough history and clinical exam. Remember to ask about recent international travel, possible exposure to communicable diseases, trauma, systemic symptoms, or risk factors.

    Next, call on your pattern recognition skills. Look for ocular signs that strongly suggest an infectious etiology, such as stellate keratic precipitates in the anterior segment or “snowballs” in the posterior segment.

    When should you perform lab testing? After the exam, all patients suspicious for infectious etiologies, as well as all intermediate and posterior uveitis cases, should undergo lab testing.

    What are some signs to look for?

    • Syphilitic retinitis. A distinguishing feature is preretinal “puffballs.” Because rates of syphilis have been increasing, especially in metropolitan areas, physicians should have a low threshold in testing for syphilis. This condition responds well to penicillin.
    • Toxoplasmosis. This is the most common cause of posterior uveitis in adults. It is typically unilateral, with elevated intraocular pressure. The commonly seen “headlight in the fog” fundus appearance is a classic sign.
    • Viral retinitis. All are true urgencies that can present with varying degrees of retinal whitening and hemorrhage. Each requires urgent paracentesis and intravitreal injection with antivirals, systemic antivirals, and monitoring for retinal detachment. Specific conditions include the following:
      • Progressive outer retinal necrosis (PORN). This occurs in immuno-compromised patients, Inflammation is typically mild and bilateral. Watch for multifocal, deep retinal opacities. The leading cause is varicella zoster.
      • Acute retinal necrosis (ARN). This occurs in immuno-competent patients. Inflammation is typically severe with elevated IOP, and small to medium retinal hemorrhage.
      • Cytomegalovirus (CMV) retinitis. This occurs in immuno-compromised patients, the infection typically has a slower course. Hemorrhages are more common with CMV retinitis compared with ARN.

    Closing thoughts. To conclude, Dr. Patel reminded physicians to consider infectious etiologies before administering steroids. Treating the underlying infection is crucial before starting immunosuppression. She noted that the clinical history and exam—not the laboratory testing—are the most important parts of a uveitis workup. Thus, it is important to take your time to narrow down the differential diagnosis.—Keng Jin Lee

    Financial disclosures. None

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