Uveitis and Ocular Inflammation
Core concepts
Know the anatomical classification (anterior, intermediate, posterior, panuveitis) and the SUN criteria for grading. Understand the differential by pattern: HLA-B27-associated anterior uveitis (ankylosing spondylitis, reactive arthritis), sarcoidosis (granulomatous, mutton-fat keratic precipitates), VKH (bilateral granulomatous panuveitis with exudative detachment), Behçet (hypopyon, retinal vasculitis), and infectious causes (toxoplasmosis, TB, syphilis, herpes). Know the masquerade syndromes (lymphoma, leukemia, retained lens material).
Traps
A common trap is missing syphilis - it is the great masquerader and should be tested in any uveitis of unknown cause. Another is VKH vs. sympathetic ophthalmia - both are bilateral granulomatous, but VKH follows a viral prodrome and has exudative detachments, while sympathetic ophthalmia follows penetrating trauma. Also know that hypopyon can be Behçet, HLA-B27, or infectious endophthalmitis - context matters.
Worked example
A young man with recurrent unilateral anterior uveitis and low back pain. Rule of thumb: recurrent unilateral anterior uveitis + sacroiliitis = HLA-B27-associated; check HLA-B27 and refer for rheumatology, and treat with topical steroids and cycloplegics.