MAR 29, 2013
This retrospective study found that the presence of certain clinical signs in eyes with uveitis, combined with a positive interferon-gamma release assay (IGRA) and positive tuberculin skin test (TST), increased the likelihood of accurately diagnosing latent tuberculosis (TB).
The study included 62 consecutive patients with uveitis associated with latent TB seen at a uveitis center in Singapore over a nine-year period. They were matched with 72 controls diagnosed with other known uveitides.
Patients were categorized as having predominantly anterior segment inflammation (anterior uveitides) or predominantly posterior segment inflammation (intermediate, posterior or panuveitides).
The authors found that latent TB was significantly associated with extensive posterior synechiae and concomitant anterior scleritis in the anterior segment inflammation group and with low-grade anterior chamber activity, retinal phlebitis and severe vitritis in the posterior segment inflammation group. Combining these clinical signs with a positive IGRA and TST improved the diagnostic performance in both groups.
No single, clinical ocular sign could conclusively suggest a tubercular cause in the study's patients. The authors recommend that a combination of clinical signs and investigations, such as IGRA and TST, be used to diagnose latent TB-associated uveitis.
They say that further prospective studies are needed to validate the study's findings in order to establish diagnostic criteria.