The Nervous System

Sarcoidosis of the nervous system may be considered for convenience under two headings; neuropathies and infiltrations of the central nervous system. Both cranial and peripheral nerves may be affected, and the changes in them may be either granulomatous or non-granulomatous. In the central nervous system, granulomatous infiltration of the meninges and diffuse and focal granulomatosis of the brain or more rarely the spinal cord may occur. There are some relatively frequent patterns of involvement; e. g. facial and other cranial nerve palsies in the uveo-parotid syndrome, and within the central nervous system, granulomatous infiltration of the meninges at the base of the brain and in the adjacent hypothalamus causing neuro-endocrine and visual disturbances. But any part of the nervous system may be affected, and the great variety of possible combinations of pathological changes can give rise to bizarre clinical features. Diagnostic difficulty may be increased by occasional association with sarcoid myopathy (Chapter 9) or with the neuro-psychiatric effects of corticosteroid treatment or of hypercalcaemia (Chapter 19).