Pure autonomic failure

[Luis Fok]

Pure autonomic failure is dysfunction of many of the processes controlled by the autonomic nervous system, such as control of blood pressure. It is not fatal.

Pure autonomic failure is caused by abnormal accumulation of synuclein in the brain.
Blood pressure may decrease when people stand, and they may sweat less and may have eye problems, retain urine, become constipated, or lose control of bowel movements.
Doctors do a physical examination and tests to look for signs of autonomic malfunction.
Treatment focuses on relieving symptoms.

(See also Overview of the Autonomic Nervous System.)
In pure autonomic failure (previously called idiopathic orthostatic hypotension or Bradbury-Eggleston syndrome), many processes regulated by the autonomic nervous system malfunction. These processes malfunction because the number of nerve cells that control them decreases. The affected cells are located in clusters (called autonomic ganglia) on either side of the spinal cord or near or in internal organs. Only the autonomic ganglia are affected. No other nerves are affected, and the brain and spinal cord are not affected.
Pure autonomic failure affects more women and tends to begin in a person’s 40s or 50s. It does not lead to death.
Pure autonomic failure is caused by abnormal accumulation of synuclein (a protein in the brain that helps nerve cells communicate, but whose function is not yet fully understood). Synuclein also accumulates in people who have Parkinson disease, multiple system atrophy, or dementia with Lewy bodies. Some people who have pure autonomic failure eventually develop multiple system atrophy or dementia with Lewy bodies.
Rapid eye movement (REM) sleep behavior disorder may occur in people with disorders that involve accumulation of synuclein, including pure autonomic failure.