BASICS

DESCRIPTION

• Sarcoidosis is a multisystem granulomatous disease of unknown etiology.

• Organs most commonly affected are the lungs, thoracic lymph nodes, skin, and central nervous system.

• Ocular involvement occurs in 10–50% of sarcoid patients. It may involve the orbit, anterior or posterior segment, or optic nerve.

EPIDEMIOLOGY

Incidence

• Substantial variation exists across ethnic groups and regions for systemic disease.

– 35–80 per 100,000 in African Americans

– 3–10 per 100,000 in European Americans

– 15–20 per 100,000 in Northern Europeans

– 1–5 per 100,000 in Southern Europeans

– 1–2 per 100,000 in Japanese

• Ocular sarcoidosis can occur at any time, may predate systemic findings, and is found in

– 10% of American patients

– 50% of European patients

– 50–90% of Japanese patients

RISK FACTORS

• African Americans are 3–10 times more likely than whites to develop sarcoid.

• The highest prevalence is in 25–50 year olds.

Genetics

• Siblings have a 5 times increased risk of developing sarcoidosis.

• HLA-DRB1 has been associated with susceptibility to sarcoidosis.

PATHOPHYSIOLOGY

Biopsy of affected tissues reveals noncaseating granulomatous inflammation.

ETIOLOGY

• No definite etiology has been identified. An abnormal immune response after exposure to minerals, organic substances, or fragments of infectious agents has been proposed as a cause.

• Macrophages, possibly in response to an inciting agent, release cytokines to recruit T-helper lymphocytes. The activated lymphocytes and macrophages are responsible for granuloma formation.

COMMONLY ASSOCIATED CONDITIONS

• Heerfordt syndrome: uveitis preceding parotid gland enlargement and disc edema

• Löfgren syndrome: erythema nodosum, bilateral hilar adenopathy, and arthralgias

DIAGNOSIS

HISTORY

• Ocular pain, photophobia, floaters, diplopia, and decreased vision may be present, although many patients are asymptomatic.

• Systemic symptoms include shortness of breath, fever, arthralgias, and skin nodules.

PHYSICAL EXAM

Several ocular signs may be present:

• Mutton-fat keratic precipitates and/or iris nodules (Koeppe/Busacca)

• Trabecular meshwork nodules and/or tent-shaped peripheral anterior synechiae

• Vitreous opacities displaying snowballs/strings of pearls

• Multiple chorioretinal peripheral lesions (active and/or atrophic)

• Nodular and/or segmental periphlebitis (candlewax drippings) and/or retinal macroaneurysm in an inflamed eye

• Optic disc nodule/granuloma and/or choroidal nodules

• Conjunctival nodules

• Lacrimal gland enlargement, often resulting in dry eye

• Proptosis may result from orbital involvement with a mass lesion.

• Diplopia may result from either cranial nerve involvement or an orbital mass lesion.

• Findings are typically bilateral though occasionally unilateral or asymmetric.

DIAGNOSTIC TESTS & INTERPRETATION

Lab

• Elevated serum angiotensin-converting enzyme (ACE) levels are found in 60–90% of patients with active sarcoidosis.

• Elevated serum lysozyme may be useful in children when ACE levels are less reliable.

• Purified protein derivative (PPD) with anergy panel may help distinguish sarcoidosis from tuberculosis. Up to 50% of sarcoidosis patients are anergic and have no response to PPD or controls.

• Abnormal liver enzyme tests

Imaging

• Chest X-ray is abnormal in 90% of sarcoidosis patients, typically revealing bilateral and symmetric hilar adenopathy or infiltrates.

– Chest CT is superior to X-ray and may be useful in patients with atypical clinical or radiographic examinations.

Diagnostic Procedures/Other

• Although definitive diagnosis requires a positive biopsy, the presumptive diagnosis is often made with positive lab tests and imaging.

– For inconclusive cases, biopsy sites include nodular lesions of the skin and conjunctiva, or the lacrimal gland.

• Whole-body gallium scans often show inflammation in areas such as the lungs, lacrimal glands, and parotid glands. A positive gallium scan and elevated ACE level is 73% sensitive and 100% specific for sarcoidosis.

• Negative testing or biopsy in a patient with high suspicion may warrant referral to a pulmonologist for pulmonary function tests or lung biopsy.

Pathological Findings

Noncaseating epithelioid cell granulomas

DIFFERENTIAL DIAGNOSIS

• Ocular sarcoidosis may masquerade as many uveitic disorders, including

– Syphilis

– Tuberculosis

– Toxoplasmosis

– Multiple sclerosis

– Lyme disease

– Vogt–Koyanagi–Harada syndrome

– Birdshot chorioretinopathy

– Intraocular lymphoma

– Sympathetic ophthalmia

– Multifocal choroiditis

• Orbital sarcoidosis may resemble

– Dacryoadenitis

– Orbital or lacrimal gland tumors

– Orbital pseudotumor

– Lipogranulomas

– Wegener granulomatosis

TREATMENT

MEDICATION

First Line

• Topical, periocular, or systemic corticosteroids

• Cycloplegia

Second Line

Patients requiring chronic treatment may benefit from nonsteroidal immunosuppressive agents (e.g., methotrexate, cyclosporine, azathioprine, infliximab), prescribed in conjunction with a uveitis specialist or rheumatologist.

ADDITIONAL TREATMENT

Issues for Referral

• Pulmonologist for lung involvement

• Rheumatologist or uveitis specialist for chronic immunosuppressive therapy

SURGERY/OTHER PROCEDURES

Secondary cataract and glaucoma may require cataract extraction or filtering surgery.

ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

• Routine examination with an ophthalmologist for recurrence of inflammation

• Primary care or pulmonologist for systemic manifestations

PATIENT EDUCATION

Foundation for Sarcoidosis Research (http://www.stopsarcoidosis.org/)

PROGNOSIS

More than 50% retain normal visual acuity, although 5% have severe bilateral visual loss of less than 20/120. Vision loss stems from posterior uveitis, glaucoma, and macular edema.

COMPLICATIONS

• Chronic uveitis

• Cystoid macular edema

• Secondary cataract

• Secondary glaucoma

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