The prevalence of sarcoidosis is 3 per 100,000 in North American whites and 47 per 100,000 in African Americans. The disorder usually presents between 20-40 years of age or thereafter and is more common in women. Clinical courses may be acute, subacute, and intermittent. Of the neurologic features, cranial neuropathies, especially of CN VII and VIII and less often II and others, are common. Symptomatic myopathy sometimes occurs, but asymptomatic muscle granulomas are more common.
Diagnostic findings are variable.
Eighteen percent have a low glucose. The Kveim-Siltzbach antigen is not readily available and in not always productive of a skin reaction. The autoimmune response is due to an undefined antigenic trigger. The various types of nervous system dysfunction may be due to effects of cytokines and, in some instances, vasculitis. Mass effect from granulomas may play a role.