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 alpha-synuclein (a protein in the brain that helps nerve cells communicate, but whose function is not yet fully understood). Alpha-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 alpha-synuclein, including pure autonomic failure.
Symptoms of Pure Autonomic Failure
The most common symptom of pure autonomic failure is
An excessive decrease in blood pressure when a person stands (orthostatic hypotension)
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). The bladder may contract involuntarily, possibly, causing urinary incontinence (uncontrollable loss of urine). People may be constipated or lose control of bowel movements (fecal incontinence). Men may have difficulty initiating and maintaining an erection (erectile dysfunction).
Diagnosis of Pure Autonomic Failure
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.
If people have REM sleep behavior disorder and orthostatic hypotension due to autonomic dysfunction, they probably have pure autonomic failure.
Doctors may do a blood test to measure levels of norepinephrine. Norepinephrine is one of the chemical messengers (neurotransmitters) used by nerve cells to communicate with each other. This blood test may distinguish pure autonomic failure from other autonomic nervous system disorders that cause similar symptoms. Low levels of norepinephrine suggest pure autonomic failure.
Treatment of Pure Autonomic Failure
Symptom relief
There is no specific treatment, so the focus is on relieving symptoms:
Constipation: A high-fiber diet and stool softeners are recommended. If constipation persists, enemas may be necessary.
Sweating abnormalities: If sweating is reduced or absent, people should avoid warm environments to avoid overheating the body.
