Sarcoidosis.

Sarcoidosis is a multisystem granulomatous disease with an unknown etiology, characterized by the presence of noncaseating granulomas in involved organs. It has a worldwide prevalence, but variable incidence among different geographical regions. The disease affects adults between 20 and 40 years of age, and it is slightly more common in women than men. Sarcoidosis is 3 to 4 times more prevalent in US blacks than whites. It usually presents with bilateral hilar adenopathy, pulmonary infiltrates and skin or eye involvement. The eye or adnexa are affected in 25 to 80% of the sarcoidosis patients. The disease can involve the orbit, lacrimal gland, anterior and posterior segments of the eye. Typical sarcoid uveitis presents with bilateral mutton-fat keratic precipitates, cells, flare, iris nodules, anterior and posterior synechia, and increased ocular pressure. Posterior involvement includes vitreitis, vasculitis, choroidal lesions, and optic neuropathy. Long term complications are common, and cystoid macular edema is the most important and sight-threatening consequence. Laboratory tests for the diagnosis of sarcoidosis include chest radiography or CT scan, bronchoscopy with bronchoalveolar lavage, angiotensin converting enzyme (ACE), Lysozyme, serum and urinary calcium, gallium scintigraphy, and biopsy. The only confirmatory test is biopsy showing classic noncaseating granulomas. Oral corticosteroids are the mainstay of treatment of sarcoidosis. Systemic cytotoxic agents like methrotrexate, azathioprine, and chlorambucil may be used in refractory cases. The visual prognosis of sarcoidosis is usually good.