Autonomic neuropathy is a group of symptoms caused by damage to nerves that regulate blood pressure, heart rate, bowel and bladder emptying, digestion, and other body functions.

Autonomic neuropathy is a form of peripheral neuropathy. Autonomic neuropathy is a group of symptoms, not a specific disease. There are many causes.

Autonomic neuropathy involves damage to the nerves that run through a part of the peripheral nervous system. The peripheral nervous system includes the nerves used for communication to and from the brain and spinal cord (central nervous system) and all other parts of the body, including the internal organs, muscles, skin, and blood vessels.

Damage to the autonomic nerves causes abnormal or decreased function of the areas connected to the problem nerve. For example, damage to the nerves of the gastrointestinal tract makes it harder to move food during digestion (decreased gastric motility).

Damage to the nerves supplying blood vessels causes problems with blood pressure and body temperature.

Autonomic neuropathy is associated with the following:

• Alcoholic neuropathy
• Diabetic neuropathy
• Parkinson's disease
• Disorders involving sclerosis of tissues
• Surgery or injury involving the nerves
• Use of anticholinergic medications

• Swollen abdomen
• Heat intolerance, induced by exercise
• Nausea after eating
• Vomiting of undigested food
• Early satiety (feeling full after only a few bites)
• Unintentional weight loss of more than 5% of body weight
• Male impotence
• Diarrhea
• Constipation
• Dizziness that occurs when standing up
• Blood pressure changes with position
• Urinary incontinence (overflow incontinence)
• Difficulty beginning to urinate
• Feeling of incomplete bladder emptying
• Fainting
• Abnormal sweating

Inspection of the abdomen may show distention, and listening to the abdomen with a stethoscope (auscultation) may show abnormal sounds indicating decreased gastric motility.

An eye examination may show sluggish pupil reaction. Examination by touch (palpation) or tapping (percussion) may indicate a distended bladder. Blood pressure examination may show a decrease upon standing (postural hypotension).

Occasionally, other symptoms may indicate disturbed functioning of the autonomic nervous system, including high blood pressure, rapid or slow heart rate, irregular heart rhythms, excessive sweating, difficulty swallowing, or other symptoms.

Special measurements of sweating and heart rate are called "autonomic testing" and can assist in diagnosis and treatment.

• An upper GI (gastrointestinal) examination with small bowel series may show decreased motility, delayed emptying of the stomach, or other abnormalities and may be used to rule out physical obstruction as a cause of vomiting or other GI symptoms.
• An EGD (esophagogastroduodenoscopy) is used to rule out physical obstruction as a cause of GI symptoms.
• An isotope study may indicate gastroparesis (decreased gastric motility).
• A VCUG (voiding cystourethrogram) or other tests of bladder function may show a flaccid bladder (inability of the bladder to contract and empty).