A 25-year-old HLA-B27 positive man presents with recurrent acute anterior uveitis (AAU). Slit lamp shows 3+ cells in the anterior chamber, fibrinous exudate, and a hypopyon. He has also been diagnosed with ankylosing spondylitis. The CHARACTERISTIC feature that distinguishes HLA-B27-associated AAU from other forms is:

• A Bilateral simultaneous involvement at onset
• B Chronic, granulomatous with mutton-fat KPs
• C Associated posterior uveitis with vitritis
• D Unilateral, acute onset, fibrinous, hypopyon formation — alternating between eyes in successive episodes ✓

Explanation

HLA-B27-associated AAU is characteristically unilateral, acute onset, non-granulomatous (fine stellate KPs), with severe fibrinous exudate and hypopyon formation. Crucially, it alternates between eyes in successive attacks — right eye in one episode, left eye in another — rather than attacking both eyes simultaneously. Bilateral simultaneous involvement suggests Behcet's disease or sarcoidosis. Mutton-fat KPs with granulomatous disease suggests sarcoid, TB, VKH, or sympathetic ophthalmia. Posterior uveitis with vitritis is not a feature of HLA-B27 AAU.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.