Sarcoidosis is a chronic disorder that affects many body systems. The majority of cases involve the lungs, but the condition can affect any area of the body. Sarcoidosis is characterized by an abnormal immune system response that produces deposits of white blood cells and abnormal tissue cells in the affected organ. A small percentage of cases will involve some portion of the nervous system (neurosarcoidosis).

Neurosarcoidosis may affect any part of the nervous system. Sudden, transient facial palsy (facial weakness) is common with involvement of cranial nerve VII. Any nerve can be affected, including the nerves of the eye and the nerves 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 or the spinal cord may also be involved. Neurosarcoidosis can cause permanent disability and, in some cases, death.

Sarcoidosis occurs in highly variable groups. In the U.S. it is more common in African-Americans, while in Europe it is more common in Caucasians. The disorder is slightly more common in people 25 to 50 years old, particularly women, but can occur at any age and to either sex. It is very rare in children. When it does affect children, sarcoidosis usually involves the lungs.

• High urine output
• Excessive thirst
• Changes in menstrual periods
• Excessive tiredness (fatigue)

• Facial palsy (weakness, drooping)
• Dementia or delirium
  • Confusion, disorientation
  • Loss of memory, judgment, or calculation skills
• Psychiatric disturbances (any)
• Seizures
• Headache
• Loss of smell
• Loss of taste, abnormal tastes
• Decreased hearing
• Vision abnormalities
• Dizziness or vertigo (abnormal sensation of movement)
• Speech impairment

• Loss of sensation in any body part
• Abnormal sensations in any body part
• Loss of movement of any body part (joint stiffness)
• Weakness of any body part

An examination may indicate single nerve dysfunction (mononeuropathy) or dysfunction of multiple peripheral nerves (sensorimotor polyneuropathy). Signs may mimic diabetes insipidus, hypopituitarism, optic neuritis, meningitis, space-occupying lesions such as tumors, or other neurologic disorders.

A history of sarcoidosis followed by neurologic symptoms is highly suggestive of neurosarcoidosis. Blood tests are nonspecific. A lumbar puncture may show signs of inflammation. Elevated levels of angiotensin converting enzyme may be found in the blood or cerebrospinal fluid (CSF).

If sarcoidosis is suspected but not already known, a chest X-ray often reveals lesions typical of the disorder. Nerve biopsy of affected nerve tissue confirms the disorder.

The probable outcome varies. Some cases resolve on their own in 4 to 6 months. Other cases continue intermittently for the rest of the person's life.

A small percentage of people with sarcoidosis of any type will die as a direct result of the disorder, most commonly when brainstem or heart involvement causes a heart attack.

• Permanent neurologic losses
• Progressive neurologic losses
• Brainstem involvement (rare, but life-threatening)