Uveitis and Ocular Immunology
This section covers uveitis and ocular immunology: classification, systemic associations, investigations, and immunosuppression. The exam tests pattern recognition and safe use of steroids.
Core rules and concepts
- Uveitis is classified anatomically as anterior, intermediate, posterior, or panuveitis; it may be granulomatous or non-granulomatous.
- HLA-B27-associated acute anterior uveitis is unilateral, recurrent, and associated with ankylosing spondylitis; treatment is topical steroid and cycloplegic.
- Sarcoidosis causes granulomatous uveitis, mutton-fat keratic precipitates, iris nodules, and hilar lymphadenopathy.
- Toxoplasmosis classically causes a focal necrotising retinochoroiditis adjacent to a scar; CMV retinitis occurs in immunosuppressed patients with haemorrhage and necrosis.
- Posterior synechiae are prevented with cycloplegics; uncontrolled inflammation causes cataract, glaucoma, and macular oedema.
Worked example
A 28-year-old man has a painful red left eye, photophobia, and decreased vision. Examination shows ciliary injection, fine keratic precipitates, cells in the anterior chamber, and a small pupil. He has a history of low back pain. The diagnosis is HLA-B27-associated acute anterior uveitis. Treat with frequent topical prednisolone acetate and cyclopentolate. Systemic work-up is guided by history; routine extensive testing is unnecessary in a typical first episode. Review within days to prevent synechiae and monitor IOP.
Traps that cost marks
Prescribing steroid without considering infection can worsen herpetic or fungal uveitis. Do not miss a masquerade syndrome such as lymphoma or retinoblastoma. Posterior synechiae and raised IOP are markers of inadequate control. In toxoplasmosis, steroids are used only with anti-parasitic cover in sight-threatening lesions.