Autonomic neuropathy Health Article

Definition

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.

Alternative Names

Neuropathy - autonomic

Causes, incidence, and risk factors

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

Symptoms

• 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

Signs and tests

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).

Other tests for autonomic neuropathy are guided by the suspected cause of the disorder, as suggested by the history, symptoms, and pattern of symptom development.

Treatment

Treatment is supportive and may need to be long-term. Several treatments may be attempted before a successful one is found.

The use of elastic stockings and sleeping with the head elevated may reduce postural hypotension. Fludrocortisone or similar medications may be beneficial in reducing postural hypotension for some people. In severe cases, Proamatine may help prevent a drop in blood pressure when standing.

Medications that increase gastric motility (such as Reglan), small, frequent meals, sleeping with the head raised up, or other measures may be used to treat reduced gastric motility.

Impotence, diarrhea, constipation, bladder problems, and other symptoms are treated as appropriate. These symptoms may respond poorly to treatment.

Expectations (prognosis)

The outcome varies. If the cause can be identified and treated, there is a chance that the nerves associated with autonomic neuropathy may repair or regenerate. The symptoms may improve with treatment, or they may persist or worsen despite treatment.

Most symptoms of autonomic neuropathy are uncomfortable but they are seldom life threatening.

Complications

• Fluid or electrolyte imbalance such as hypokalemia (if excessive vomiting or diarrhea)
• Malnutrition
• Kidney failure (associated with reflux of urine)
• Psychologic/social effects of impotence
• Injuries from falls (associated with postural dizziness)