Time critical in infectious uveitis

Infectious uveitis is usually diagnosed based on the clinical findings with consideration of the duration and progression of the disorder, the appearance of the inflammation, and the extent of the retinal involvement.

"When faced with advanced cases of posterior uveitis, with a presumed infection, time is of the essence," said Dr Young, associate professor of ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachussetts, USA. "Available diagnostic polymerase chain reaction (PCR) testing has been shown to be extremely useful for detecting a wide range of pathogens, particularly viral pathogens."

Differentiating uveitic infections

The differential diagnosis in patients with vitritis includes toxoplasmic retinitis, acute retinal necrosis, endophthalmitis, tuberculosis, syphilis, sarcoidosis, autoimmune diseases, intraocular lymphoma and Toxocara infections.

An important step in these cases is a thorough history.

"The rates of progression and duration are the most important bits of information," Dr Young said. "Don't be fooled if a patient presents with 2 to 3 days of increased ocular redness and pain. This does not mean that the patient has had this for only 2 to 3 days. Once a true 2- to 3-day course of rapid progression has been established, acute retinal necrosis or bacterial endophthalmitis must be considered."

At the other end of the spectrum, if a patient cannot accurately define the time of progression, syphilis or tuberculosis might be considerations, but in these cases, a rapid diagnosis is not as pressing as in acute cases. In cases in which the patient has been symptomatic for weeks, Toxoplasma infection and fungal endophthalmitis are considerations, she advised.

Determining the status of the patient's immune system is important. If a patient appears healthy and robust, progressive outer retinal necrosis (PORN) and cytomegalovirus (CMV) retinitis are likely not issues.