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Pure Autonomic Failure

By Phillip Low, MD, Mayo Clinic College of Medicine

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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.

  • The cause is usually unknown but sometimes is an autoimmune disorder.

  • 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.

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 nerve cells that control them malfunction. 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. The brain and spinal cord are not affected, nor are other peripheral nerves (nerves outside the brain and spinal cord).

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 probably caused by abnormal accumulation of alpha-synuclein (a protein in the brain whose functions are unknown). Alpha-synuclein also accumulates in people who have Parkinson disease, multiple system atrophy, or Lewy body dementia. Some people who have pure autonomic failure eventually develop multiple system atrophy or Lewy body dementia. REM (rapid eye movement) sleep behavior disorder may occur in people with disorders that involve accumulation of alpha-synuclein, including pure autonomic failure.


The most common symptom of pure autonomic failure is

People may sweat less and become intolerant of heat. The pupils may not widen (dilate) and narrow (constrict) normally. Vision may be blurred. People may have difficulty emptying the bladder (urine retention). They may be constipated or lose control of bowel movements (fecal incontinence). Men may have difficulty initiating and maintaining an erection (erectile dysfunction).


  • A doctor's evaluation

  • Tests to rule out other possible causes

Doctors check for signs of autonomic dysfunction during the physical examination and with tests. For example, doctors measure levels of norepinephrine, one of the chemical messengers (neurotransmitters) used by nerve cells to communicate with each other.

No test can confirm the diagnosis, so doctors diagnose this disorder by excluding other disorders.


  • Symptom relief

There is no specific treatment, so the focus is on relieving symptoms.

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