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.
Dr Lucy H. Young, PhD, reviewed the various features of uveitic infections to help clinicians narrow the field of pathogens
and begin therapy in a timely fashion before the diagnostic test results become available. She spoke during the Retina Subspecialty
Day at the annual meeting of the American Academy of Ophthalmology.
"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."
However, because of the time required to receive PCR test results, clinicians have to start empiric therapy immediately before
the test results become available.
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.