Sympathetic Nervous System Disorders

The sympathetic nervous system is a part of the autonomic nervous system. Among other things, it activates what is commonly referred to as your "fight or flight response."

Horner Syndrome

• Horner syndrome generally affects one side of your face. Symptoms include a drooping eye with a smaller pupil and decreased sweating. Horner syndrome is not a disease, but a sign of a problem such as a stroke, tumor, or spinal cord injury.

Multiple System Atrophy

• Multiple system atrophy impairs your body's involuntary functions, such as blood pressure heart rate and digestion. Symptoms often resemble Parkinson's disease. It is a progressive disorder and ultimately fatal.

Holmes-Adie Syndrome

• Holmes-Adie syndrome is characterized by one eye with a pupil that is larger than normal that constricts slowly in bright light, and the absence of deep tendon reflexes. It is believed to be caused by a bacterial infection. The loss of deep tendon reflexes is permanent, but the vision problems can be treated with glasses.

Orthostatic Hypotension

• Orthostatic hypotension is a sudden fall in blood pressure that occurs when you stand up. It may be associated with several neurological disorders, so treatment varies.

Vasovagal Syncope

• Vasovagal syncope causes a sudden drop in your heart rate and blood pressure, which reduces blood flow to your brain and causes you to faint. This reaction is typically triggered by something such as the sight of blood. It is usually harmless and can be treated with medication or therapy.