Residency · Residency · Ophthalmology
Posterior Uveitis and Retinal Vasculitis
Introduction
Posterior uveitis encompasses inflammatory conditions affecting the choroid, retina, and vitreous. Retinal vasculitis, often occurring in conjunction with posterior uveitis, involves inflammation of retinal arteries, veins, or capillaries. Together, these entities represent some of the most vision-threatening forms of intraocular inflammation and demand a systematic diagnostic and therapeutic approach.
Anatomy and Pathophysiology
Relevant Structures
Choroid: highly vascular tissue supplying the outer retina; primary site of choroiditis. Retinal pigment epithelium (RPE): barrier between choroid and neurosensory retina; disruption leads to photoreceptor damage. Retinal vasculature: inner blood-retinal barrier; inflammation causes leakage, occlusion, and ischemia.
Immunologic Mechanisms
Autoimmune targeting of retinal antigens (e.g., S-antigen, interphotoreceptor retinoid-binding protein) Molecular mimicry following infectious triggers. Breakdown of immune privilege via disruption of the blood-retinal barrier. Role of Th1, Th17, and regulatory T-cell imbalance.
Classification
By Anatomic Pattern
Focal choroiditis: discrete lesion (e.g., toxoplasmosis) Multifocal choroiditis: scattered lesions (e.g., sarcoidosis, histoplasmosis) Diffuse choroiditis: widespread involvement (e.g., sympathetic ophthalmia, Vogt-Koyanagi-Harada disease) Retinal vasculitis: phlebitis (more common) vs. arteritis; may be isolated or part of systemic vasculitis.
Infectious vs. Non-Infectious
Infectious: toxoplasmosis, CMV retinitis, ocular tuberculosis, syphilis, toxocariasis, fungal endophthalmitis. Non-infectious: sarcoidosis, Behcet disease, birdshot chorioretinopathy, serpiginous choroidopathy, VKH.
Clinical Evaluation
Symptoms
Painless decreased vision, floaters, scotomata. Photopsia may indicate retinal traction or inflammation at the vitreoretinal interface.
Examination Findings
Vitritis (graded 0 to 4+ using the SUN/NEI scale) Chorioretinal lesions: active lesions are yellow-white with indistinct borders; inactive lesions show chorioretinal atrophy and pigment clumping. Retinal vasculitis: perivascular sheathing, vessel occlusion, retinal hemorrhages. Cystoid macular edema, epiretinal membrane, optic disc edema.
Diagnostic Testing
Fluorescein angiography (FA): vessel wall staining, leakage, capillary non-perfusion, optic disc hyperfluorescence. Indocyanine green angiography (ICGA): hypofluorescent dark dots in VKH, stromal choroidal vasculitis. Optical coherence tomography (OCT): macular edema quantification, subretinal fluid, RPE changes. OCT angiography: non-invasive evaluation of capillary dropout and neovascularization.
Laboratory Workup
Directed by clinical suspicion; avoid "shotgun" panels. Common studies: CBC, ESR/CRP, ACE, lysozyme, chest X-ray, RPR/FTA-ABS, QuantiFERON-TB Gold. Aqueous or vitreous sampling: PCR for herpesviruses, toxoplasmosis; cytology to rule out masquerade syndromes. HLA-A29 for birdshot chorioretinopathy; HLA-B51 for Behcet disease.
Major Disease Entities
Toxoplasmosis
Most common cause of infectious posterior uveitis worldwide. Classic "headlight in the fog" appearance: active white retinal lesion adjacent to a pigmented scar with overlying vitritis. Treatment: pyrimethamine + sulfadiazine + folinic acid; or trimethoprim-sulfamethoxazole; add corticosteroids after 48 hours of antimicrobials.
Behcet Disease
Occlusive retinal vasculitis with arteritis and phlebitis. Recurrent hypopyon uveitis, oral and genital ulcers. High risk of vision loss without early immunomodulatory therapy (anti-TNF agents preferred)
Vogt-Koyanagi-Harada (VKH) Disease
Bilateral granulomatous panuveitis with exudative retinal detachments. Systemic features: meningismus, poliosis, vitiligo, alopecia. Early aggressive corticosteroid therapy; often requires steroid-sparing agents.
Sarcoidosis
"Great mimicker"; can cause any pattern of uveitis. Periphlebitis with "candle-wax drippings," granulomatous inflammation, optic disc granulomas.
| Disease | Key Fundus Finding | Systemic Clue | First-Line Treatment |
|---|---|---|---|
| Toxoplasmosis | "Headlight in fog"; satellite scar | Immunocompromised; congenital | Pyrimethamine + sulfadiazine + folinic acid |
| Behcet disease | Occlusive retinal vasculitis | Oral/genital ulcers; HLA-B51 | Anti-TNF agents (early IMT) |
| VKH | Bilateral exudative RD; sunset glow fundus | Meningismus, poliosis, vitiligo | High-dose systemic corticosteroids |
| Sarcoidosis | Candle-wax drippings; disc granuloma | Bilateral hilar lymphadenopathy; elevated ACE | Corticosteroids; steroid-sparing IMT |
| CMV retinitis | Hemorrhagic necrosis; "pizza pie" | CD4 < 50; HIV/AIDS | Ganciclovir/valganciclovir |
| Ocular TB | Choroidal tubercles; serpiginous-like | PPD+/QuantiFERON+; endemic area | Anti-TB therapy + corticosteroids |
| Syphilis | Any pattern; "great imitator" | RPR/FTA-ABS positive | IV penicillin G |
Management Principles
Infectious Etiologies
Targeted antimicrobial therapy is paramount; corticosteroids without coverage can be catastrophic. Intravitreal injections (e.g., foscarnet for CMV, clindamycin for toxoplasmosis) for severe cases.
Non-Infectious Etiologies
Corticosteroids: topical (limited posterior penetration), periocular, intravitreal (triamcinolone, dexamethasone implant), systemic. Immunomodulatory therapy: indicated for chronic or recurrent disease, bilateral involvement, steroid dependence. Step-ladder approach: antimetabolites (mycophenolate, methotrexate), which leads to calcineurin inhibitors, which leads to biologic agents (adalimumab, infliximab)
Surgical Considerations
Diagnostic vitrectomy for atypical presentations or suspected masquerade. Therapeutic vitrectomy for non-clearing vitreous hemorrhage, epiretinal membrane, tractional detachment.
Complications
Cystoid macular edema (most common cause of vision loss) Retinal neovascularization and vitreous hemorrhage. Tractional and rhegmatogenous retinal detachment. Secondary glaucoma, cataract, band keratopathy, phthisis bulbi.
Key Clinical Pearls
Always exclude infection before initiating corticosteroids for posterior uveitis. Toxoplasmosis is the most common cause of infectious posterior uveitis; look for the classic satellite lesion adjacent to an old scar. Behcet disease requires early biologic therapy to prevent irreversible retinal ischemia and vision loss. Fluorescein angiography is essential for detecting subclinical vasculitis and guiding treatment decisions.
References
- Jabs DA, Nussenblatt RB, Rosenbaum JT. Standardization of Uveitis Nomenclature (SUN) Working Group. Am J Ophthalmol. 2005;140(3):509-516.
- Cunningham ET Jr, Baxter J. Posterior uveitis: a practical approach. Int Ophthalmol Clin. 2015;55(3):1-18.
- Rosenbaum JT, Dick AD. The eyes have it: a rheumatologist's view of uveitis. Nat Rev Rheumatol. 2018;14(11):623-624.
- Standardization of Uveitis Nomenclature (SUN) Working Group. Classification criteria for Behcet disease uveitis. Am J Ophthalmol. 2021;228:338-346.