Neurosarcoidosis is a complication of sarcoidosis in which inflammation and abnormal deposits occur in the brain, spinal cord, and other areas of the nervous system.

Sarcoidosis is a long-term (chronic) disorder that affects many parts of the body, mostly the lungs. In a small number of patients, the disease involves some part of the nervous system. This is called neurosarcoidosis.

Neurosarcoidosis may affect any part of the nervous system. Sudden, facial weakness (facial palsy)is common and involves the nerves to the muscles of the face (cranial nerve VII). Any nerve in the skull can be affected, including those in the eye and those that control taste, smell, or hearing.

The condition can also affect a part of the brain called the hypothalamus, which is involved in regulating many body functions such as temperature, sleep, and stress responses.

Muscle weakness or sensory losses can occur with peripheral nerve involvement. Other areas of the brain, including the pituitary gland at the base of the brain, or the spinal cord may also be involved.