SARCOIDOSIS

Sarcoidosis is an idiopathic, granulomatous inflammation that may affect nearly any part of the body. Ocular involvement may be present in up to 50% of patients with histologically proven sarcoidosis. Often sarcoidosis is not a known diagnosis in a patient presenting with uveitis.

Symptoms

Posterior segment involvement is often associated with decreased vision due to floaters and vitritis. Symptoms of anterior uveitis including photophobia, conjunctival injection, and eye pain may be presenting signs of sarcoid uveitis. Decreased vision may be due to posterior uveitis from chronic macular edema, epiretinal membrane formation, and retinal ischemia due to vasculitis.

Clinical Features

Retinal lesions occur in approximately 25% of patients with sarcoid-associated uveitis. Vitritis is a major manifestation of posterior segment involvement with sarcoidosis. Retinal vasculitis is the most common retinal abnormality associated with sarcoidosis. The vasculitis primarily affects the venules and may be associated with focal perivascular exudates (“candlewax drippings”). The vasculitis may lead to vascular occlusion, retinal ischemia, and retinal neovascularization. The chorioretinitis of sarcoidosis is nonspecific, although focal choroidal granulomas have been reported. These granulomas are associated with overlying neurosensory detachment. Optic nerve granulomas may occur. Posterior uveitis may lead to the development of cystoid macular edema (CME) and epiretinal membrane formation.

Ancillary Testing

Fluorescein angiography is important in the diagnosis and monitoring of CME. In cases with severe vitritis, fluorescein angiography may help identify vasculitis and retinal lesions. Choroidal granulomas demonstrate early hypofluorescence and late hyperfluorescent staining.

Pathology/Pathogenesis

Sarcoid nodules consist of noncaseating epithelioid granulomatous disease.

Treatment/Prognosis

Sarcoid uveitis usually responds well to corticosteroid therapy. Treatment of eye disease is commonly part of treatment of the systemic disease. The nature of the disease and process usually requires prolonged therapy. Nonsteroidal anti-inflammatory medications may supplement systemic therapy or even periocular steroid treatment. Cystoid macular edema requires the use of systemic or periocular corticosteroids. Neovascularization may respond to control of ocular inflammation but may require peripheral scatter laser photocoagulation if there is extensive nonperfusion.

Systemic Evaluation

The ultimate diagnosis of sarcoidosis depends on histologic confirmation of sarcoid granulomas. Less invasive testing to support clinical suspicion of disease include the demonstration of hilar adenopathy on chest x-ray, gallium scan demonstration of inflammatory cell infiltration, and elevated angiotensin-converting enzyme levels.

Sarcoidosis commonly involves the eye. Anterior segment manifestations include iritis and iridocyclitis. This woman presented with pain, redness, and photophobia. She had prominent keratic precipitates.

Focal choroidal granulomas may be observed. These usually are associated with overlying subretinal fluid.

The characteristic retinal finding in patients with sarcoidosis is a periphlebitis described as “candlewax drippings.”

Fluorescein angiogram of the same patient reveals marked hyperfluorescence as a result of leakage in the region of the granuloma.

Sarcoidosis may mimic the inflammatory white dot syndromes with multifocal choroidal infiltrates. This patient had sarcoidosis confirmed by lung biopsy.

Characteristic vitreous findings include vitritis and vitreous “snowballs.” This patient also had peripheral retinal neovascularization with hemorrhage.

SERPIGINOUS CHOROIDITIS

Serpiginous choroiditis is a chronic, progressive inflammatory condition affecting the choroid and retinal pigment epithelium (RPE). Recurrent attacks are the rule and can occur weeks to years after the initial event. Serpiginous choroiditis typically affects middle-aged individuals (30 to 60 years of age); there may be a slight male preponderance. Serpiginous choroiditis is bilateral but may be asymmetric.

Symptoms

Symptoms include blurred vision, central or paracentral scotomas, metamorphopsia, and visual field loss. Individuals may be asymptomatic before foveal involvement.

Clinical Features

The anterior segment is usually normal. If present, vitritis is mild. Serpiginous choroiditis involves the peripapillary region and macula. Acute lesions are slightly ill-defined, gray-white, jigsaw puzzle-shaped lesions at the level of the choriocapillaris and RPE. The active lesions may be associated with shallow subretinal fluid. Acute lesions are commonly located adjacent to atrophic scars. As the acute lesion clears, extensive atrophy of the choriocapillaris, RPE, and retina is seen. Areas of retinal pigment epithelial hyperpigmentation and subretinal fibrosis are common. Choroidal neovascularization

may develop.

Ancillary Testing

Intravenous fluorescein angiography (IVFA) shows early hypofluorescence of the active lesions secondary to either an inflammatory occlusion of the choriocapillaris or blocked fluorescence by the edematous RPE. The late phase of the study demonstrates hyperfluorescence of the border of the active lesion that may extend centrally.

Indocyanine green angiography is divided into four stages: (1) hypofluorescent lesions in the subclinical or choroidal stage; (2) hypofluorescent lesions in the active stage, larger than those defined on IVFA; (3) hyperfluorescence in the healing/subhealing stage; and (4) hypofluorescent lesions with clearly defined margins in the inactive stage. Electroretinogram and electro-oculogram findings are usually normal.

Pathology/Pathogenesis

The etiology of serpiginous choroiditis is not completely understood. A possible immune-mediated mechanism has been proposed due to an increased frequency of HLA-B7 and retinal S-antigen associations. An association with varicella-zoster infection also has been postulated. Elevated von Willebrand factor has been reported, although the significance of this finding is unclear.

Treatment/Prognosis

The prognosis for serpiginous choroidopathy is guarded. Visual loss results from direct foveal involvement or the development of choroidal neovascularization. Rarely, individuals with foveal involvement may recover central vision, although visual recovery is usually incomplete.

Treatment involves the use of immunosuppressive agents such as prednisone, azathioprine, and cyclosporine. Acyclovir has been reported with limited success. Laser photocoagulation may be helpful in cases of choroidal neovascularization but has not been proven to limit the active inflammatory lesions.

Systemic Evaluation

Most individuals with serpiginous choroiditis are healthy and require no systemic evaluation.

Serpiginous choroiditis involves the posterior fundus. Active choroiditis is characterized by slightly ill-defined, yellowish white areas adjacent to old chorioretinal atrophy.

Fluorescein angiography of the active lesions reveals early hypofluorescence followed by late hyperfluorescence.

The active lesions become atrophic over the course of weeks. The atrophic regions may assume a jigsaw puzzle-like configuration.

Late-phase angiogram of the same patient reveals late hyperfluorescence, which is most prominent along the border of the active lesion.