The neurological complications of systemic sarcoidosis.

Involvement of the central nervous system in sarcoidosis arises predominantly due to infiltration of the meninges leading to pachymeningitis with cranial neuropathies, hydrocephalus, encephalopathy and hypothalamic dysfunction. Less frequently cerebral mass lesions occur, and spinal cord lesions have been reported. Involvement of the peripheral nervous system leading to radiculopathies, peripheral neuropathy and mononeuritis multiplex also occurs and muscle involvement may be difficult to diagnose until advanced stages. If neurological syndromes arise in patients with established biopsy proven systemic sarcoidosis, the diagnosis is usually easy to make, but oftentimes patients may present de novo with neurological symptoms and signs without systemic involvement. Subsequent investigations may lead on to the identification of systemic granulomata, but on other occasions these are not found; it has not yet been established what relationship such cases has to those with the systemic disorder in whom neurological complications arise.