Be wary of dangerous masquerades in idiopathic uveitis

Patients who have masquerade syndromes-underlying disorders that present with signs and symptoms that appear toindicate idiopathic uveitis-are among the most challenging cases to ophthalmologists, said Scott Whitcup, MD.

Infection and malignancy must be ruled out first, said Dr. Whitcup, executive vice president and head of research anddevelopment, Allergan, and a member of the clinical faculty at Jules Stein Eye Institute, University of California at LosAngeles.

Retinoblastoma, leukemia, uveal melanoma, intraocular lymphoma, and other malignancies of the eye can masquerade as uveitis.Many of these patients will complain about floaters or blurred vision. Fluorescein angiography can help identify retinallesions, and a diagnosis of an intraocular malignancy can be made based on identification of malignant cells in the cerebralspinal fluid or vitreous.

"Handle the malignant specimens promptly," Dr. Whitcup said. "Malignant cells will tend to die after 20 to 30 minutes, so youreally want [them] processed immediately. If you wait until the surgery is over, and the specimens are hours old or, worse,sent the next day, you'll miss the diagnosis more often than you'll make it."

Cytokine profiles of the vitreous also can help. If the level of interleukin-10 is greater than the inflammatory level ofinterleukin-6, there is a high suspicion of lymphoma, he said.

Also be aware of metastatic disease to the eye, which can masquerade as inflammatory or infectious uveitis.

Non-malignant conditions that can masquerade as uveitis include trauma, choroidal osteoperosis, and asteroid hyalosis.According to Dr. Whitcup, a good rule-of-thumb for diagnosis in patients who present with a masquerade syndrome isunresponsiveness to anti-inflammatory therapy.

"Consider masquerade syndrome in your differential diagnosis of idiopathic uveitis," Dr. Whitcup said. "It allows promptinstitution of appropriate therapy and avoids unnecessary treatment."