Sarcoidosis

Description

Sarcoidosis is a diverse systemic disease, characterized by the development of epithelioid granulomas & other changes in multiple organ systems, with the lungs most often affected. Its etiology is considered idiopathic, although it may be a response to an unidentified organism or antigen. Clinical disease occurs when granulomata affect the normal architecture and function of involved tissues.

Systemic Signs

(a) Lung involvement (about 90%): Chest X-ray (CXR) may show bilateral and symmetrical hilar lymphadenopathy and pulmonary infiltration. Symptoms may include difficulty in breathing (dyspnea), fatigue and cough.

(b) Skin lesions (about 30%), including erythema nodosum (red nodules on legs or arms) and cutaneous granulomata.

(c) Ocular signs (about 20%): see below

(d) Nervous system (about 10%)

(e) Other e.g. liver, spleen, lymph nodes, salivary glands, joints, heart, muscle and bones.

Ocular Symptoms

These include a red eye, blurred vision, pain, photophobia and lacrimation.

Ocular Signs

(a) Uveitis:

• Most often a unilateral anterior granulomatous uveitis, with mutton fat keratic precipitates. However, the uveitis may be bilateral or nongranulomatous.
• Vitritis, with fluffy white infiltrate opacities (“string of pearls”), may be present.
• Busacca nodules on the iris surface
• Koeppe nodules on the pupillary margin

(b) Glaucoma secondary to the uveitis

(c) Anterior ocular signs may also include:

• Lacrimal gland disease (keratoconjunctivitis sicca) in 20-30% of patients
• Conjunctival slightly raised yellow lesions
• Band keratopathy

(d) Posterior signs are usually bilateral and may include:

• Periphlebitis: white exudations affecting the equatorial retinal veins
• Retinal vein occlusions, where granulomas may compress the vasculature
• Retinal hemorrhages
• Chorioretinitis
• Macular edema – cystoid
• Optic disc edema or granulomas
• Neovascularization affecting the choroid, optic disc or peripheral retina

(e) Neurological effects: visual pathways may be affected by granulomas, causing visual field restriction, facial nerve palsy, papilledema

(f) The orbit or extraocular muscles may also be affected by granulomas, causing diplopia, palsies or proptosis

Prevalence

Occurs most frequently in young adults (20-40 years), particularly in women and darker skinned races. Overall uncommon to rare.

Significance

Sarcoidosis is potentially vision and life threatening if uncontrolled.

Differential Diagnosis

Lymphoma – primary intraocular (Large reticulum cell sarcoma)

See Also

Syphilis, HIV, Lupus, Lyme, Sickle cell disease

Management

Additional Investigations

Diagnosis of sarcoidosis is usually assisted by CXR. Angiotension converting enzyme (ACE) is usually elevated. Also consider biopsy of nodules in the lacrimal gland, conjunctiva, skin, lymph node or lung. Fluorescein angiography maybe indicated to confirm posterior segment neovascularization.

Laboratory tests

Blood tests are indicated for autoimmune, rheumatologic, infectious and inflammatory diseases, especially in the presence of atypical uveitis or other anomaly.

Topical and Oral medications

Uveitis and sarcoid retinopathy are treated with topical or oral steroids; occasionally additional immunosuppressants are needed. Initial treatment may be prednisolone acetate 1% q1h to q6h. Consider tear supplements and punctual occlusion if dry eye is present.

Laser treatment and injection

Photocoagulation may be indicated for posterior segment neovascularization. Choroidal neovascularization may be treated with repeated doses of anti- vascular endothelial growth factor (anti-VEGF) drugs delivered by an intravitreal injection.

Review

Routine review as part of a multidisciplinary approach is essential. Asymptomatic patients need 6 month reviews for uveitis, cataract, glaucoma, dry eye or neurological signs.

Prognosis

Although sarcoidosis may remain stable for some patients, in others it tends to follow a waxing and waning course. Good vision can be expected if ocular inflammation or retinopathy can be kept under control.