Sarcoidosis

Sarcoidosis is a chronic, multisystem disorder of unknown cause characterized in affected organs by an accumulation of T lymphocytes and mononuclear phagocytes, noncaseating epithelioid granulomas, and derangements of the normal tissue architecture. The disease is often acute or subacute and self-limiting, but in many individuals it is chronic, waxing and waning over many years.

Cause of Sarcoidosis

The cause of sarcoidosis is unknown. Various infectious and noninfectious agents have been implicated, but there is no proof that any specific agent is responsible.

Sarcoidosis is a relatively common disease affecting individuals of both sexes and almost all ages, races, and geographic locations. Females appear to be slightly more susceptible than males. Cases of sarcoidosis have been described in all of the major races, and the disease is found throughout the world. It has been suggested that sarcoidosis is more common in certain geographic areas such as the southeastern part of the United States, but when case-matched controls have been used, these geographic differences are less convincing.

So-called acute or subacute sarcoidosis develops abruptly over a period of a few weeks and represents 20 to 40% of all cases. These individuals usually have constitutional symptoms such as fever, fatigue, malaise, anorexia, or weight loss.

Sarcoidosis also can involve old surgical scars and tattoos. Although it may be disfiguring, cutaneous sarcoidosis rarely causes major problems. Clubbing of the fingers is occasionally observed in sarcoidosis, usually in association with extensive pulmonary fibrosis.

With current microsurgical techniques, most areas of the basal meninges can be accessed for biopsy via a limited craniotomy. In a series from the Mayo Clinic reported by Cheng et al., MRI demonstrated meningeal enhancement in 47% of patients undergoing meningeal biopsy. Biopsy of an enhancing region was diagnostic in 80% of cases; biopsy of nonenhancing regions was diagnostic in only 9%; sarcoid (31%) and metastatic adenocarcinoma (25%) were the most common conditions identified.

Aphthous oral lesions, genital ulcers, and hypopyon suggest Behcet's syndrome. Hepatosplenomegaly suggests lymphoma, sarcoid, tuberculosis, or brucellosis.

Diagnosis of Sarcoidosis

For a typical case, the diagnosis of sarcoidosis is made by a combination of clinical, radiographic, and histologic findings. In a young adult with constitutional complaints, respiratory symptoms, erythema nodosum, blurred vision, and bilateral hilar adenopathy, the diagnosis is almost always sarcoidosis. Commonly, however, the findings are more subtle.

Treatment of Sarcoidosis

The therapy of choice for sarcoidosis is glucocorticoids, Various other drugs have been tried, including indomethacin, oxyphenbutazone, chloroquine, hydroxychloroquine, methotrexate, p-aminobenzoate, allopurinol, levamisole, azothioprine, and cyclophosphamide; but there is no evidence, apart from anecdotal, uncontrolled reports, to support their efficacy. Cyclosporine is ineffective for the pulmonary manifestations of the disease; anecdotal reports suggest that it may be useful in extrathoracic sarcoid not responding to glucocorticoids.