Autonomic neuropathy occurs when the nerves that control involuntary bodily functions are damaged. This may affect blood pressure, temperature control, digestion, bladder function and even sexual function.

The nerve damage interferes with the messages sent between the brain and other organs and areas of the autonomic nervous system, such as the heart, blood vessels and sweat glands.

While diabetes is generally the most common cause of autonomic neuropathy, other health conditions — even an infection — may be to blame. Some medications also may cause nerve damage. Symptoms and treatment will vary based on which nerves are damaged.

Signs and symptoms of autonomic neuropathy vary based on the nerves affected. They may include:

Dizziness and fainting when standing caused by a sudden drop in blood pressure.

Urinary problems, such as difficulty starting urination, incontinence, difficulty sensing a full bladder and inability to completely empty the bladder, which can lead to urinary tract infections.

Sexual difficulties, including problems achieving or maintaining an erection (erectile dysfunction) or ejaculation problems in men and vaginal dryness, low libido and difficulty reaching orgasm in women.

Difficulty digesting food, such as feeling full after a few bites of food, loss of appetite, diarrhea, constipation, abdominal bloating, nausea, vomiting, difficulty swallowing and heartburn, all due to changes in digestive function.

Sweating abnormalities, such as sweating too much or too little, which affects the ability to regulate body temperature.

Sluggish pupil reaction, making it difficult to adjust from light to dark and seeing well when driving at night.

Exercise intolerance, which may occur if your heart rate stays the same instead of adjusting in response to your activity level.

When to see a doctor

Seek medical care promptly if you begin experiencing any of the signs and symptoms of autonomic neuropathy, particularly if you have diabetes and it's poorly controlled.

If you have type 2 diabetes, the American Diabetes Association (the Association) recommends annual autonomic neuropathy screening for people with type 2 diabetes as soon as you've received your diabetes diagnosis. For people with type 1 diabetes, the Association advises annual screening beginning five years after diagnosis.

Many health conditions can cause autonomic neuropathy. It may also be a side effect of treatments for other diseases, such as cancer. Some common causes of autonomic neuropathy include:

Abnormal protein buildup in organs (amyloidosis), which affects the organs and the nervous system.

Autoimmune diseases, in which your immune system attacks and damages parts of your body, including your nerves. Examples include Sjogren's syndrome, systemic lupus erythematosus, rheumatoid arthritis and celiac disease. Guillain-Barre syndrome is an autoimmune disease that happens rapidly and can affect autonomic nerves.

Autonomic neuropathy may also be caused by an abnormal attack by the immune system that occurs as a result of some cancers (paraneoplastic syndrome).

Diabetes, which is the most common cause of autonomic neuropathy, can gradually cause nerve damage throughout the body.

Injury to nerves caused by surgery or radiation to the neck.

Treatment with certain medications, including some drugs used in cancer chemotherapy.

Other chronic illnesses, such as Parkinson's disease, multiple sclerosis and some types of dementia.

Certain infectious diseases. Some viruses and bacteria, such as botulism, Lyme disease and HIV, can cause autonomic neuropathy.

Diabetes. Diabetes, especially when poorly controlled, increases your risk of autonomic neuropathy and other nerve damage. You’re at greatest risk if you have had the disease for more than 25 years and have difficulty controlling your blood sugar, according to the National Institute of Diabetes and Digestive and Kidney Diseases.

Additionally, people with diabetes who are overweight or have high blood pressure or high cholesterol have a higher risk of autonomic neuropathy.

Other diseases. Amyloidosis, porphyria, hypothyroidism and cancer (usually due to side effects from treatment) may also increase the risk of autonomic neuropathy.

First, you'll probably see your primary care physician. If you have diabetes, you may see your diabetes specialist (endocrinologist). However, you may be referred to a specialist in nerve disorders (neurologist).

You may need to see other specialists depending on the part of your body affected by neuropathy: for example, a cardiologist for problems with your blood pressure or heart rate, or a gastroenterologist for digestive difficulties.

Arrive at your appointment well-prepared. Here are some tips to help you prepare yourself and know what to expect from your doctor.

What you can do

Ask about any restrictions before the appointment. Find out if you should do anything in advance, such as fasting before certain tests.

Write down any symptoms you're experiencing, even those that may seem unrelated to autonomic neuropathy.

Make a list of all medications (including over-the-counter), vitamins or supplements that you take.

Ask a family member or friend to come with you. Bring someone who can help you remember the information you and your doctor discuss. Family members can learn more about autonomic neuropathy if they attend appointments with you. For example, if you don't know when your blood pressure is too low, you may pass out (faint). Your family members will need to know what to do.

Write down questions to ask your doctor.

Since appointments can be short, prepare a list of questions before you go. Some basic questions to ask your doctor about autonomic neuropathy may include:

Why did I develop autonomic neuropathy?

Could anything else cause my symptoms?

What kinds of tests do I need? Will I need to do anything to prepare?

Is autonomic neuropathy temporary or chronic?

What are the available and recommended treatments for autonomic neuropathy?

What are the treatment side effects?

Are there any alternatives to the treatment that you're suggesting?

Is there anything I can do on my own to help manage autonomic neuropathy?

I have other health conditions. How can I best manage those with autonomic neuropathy?

Do I need to follow a special diet?

Are there any activity restrictions that I need to follow?

Do you have any printed materials or recommended websites that you can share with me?

Don't hesitate to ask additional questions that may come up during your appointment.

What to expect from your doctor

Your doctor is likely to ask you a number of questions. Be prepared to answer these types of questions to allow more time for your own:

When did you first begin experiencing symptoms?

Have your symptoms been continuous or occasional?

How severe are your symptoms?

Does anything seem to improve your symptoms?

What, if anything, appears to worsen your symptoms?

Autonomic neuropathy is a possible complication of a number of diseases, and the tests you'll need often depend on your symptoms and risk factors for autonomic neuropathy.

When you have known risk factors for autonomic neuropathy

If you have conditions that increase your risk of autonomic neuropathy (such as diabetes) and have symptoms of the condition, extensive testing may not be necessary. Your doctor may perform a physical exam and ask about your symptoms.

If you are undergoing cancer treatment with a drug known to cause nerve damage, your doctor will check for signs of neuropathy.

When you don't have risk factors for autonomic neuropathy

If you have symptoms of autonomic neuropathy but don't have risk factors, the diagnosis may be more involved. Your doctor will probably review your medical history, discuss your symptoms and do a physical exam.

Your doctor may perform tests to evaluate autonomic functions, which may include:

Tilt-table test. This test monitors the response of blood pressure and heart rate to changes in posture and position, simulating what occurs when you stand up after lying down. You lie flat on a table, which is then tilted to raise the upper part of your body. Normally, your body narrows blood vessels and increases heart rate to compensate for the drop in blood pressure. This response may be slowed or abnormal if you have autonomic neuropathy.

A simpler way test for this response involves standing for a minute, then squatting for a minute and then standing again while blood pressure and heart rate are monitored.

Gastrointestinal tests. Gastric-emptying tests are the most common tests to check for digestive abnormalities such as slow digestion and delayed emptying of the stomach (gastroparesis). These tests are usually done by a doctor who specializes in digestive disorders (gastroenterologist).

Quantitative sudomotor axon reflex test. This test evaluates how the nerves that regulate your sweat glands respond to stimulation. A small electrical current passes through four capsules placed on your forearm, foot and leg, while a computer analyzes the response of your nerves and sweat glands. You may feel warmth or a tingling sensation during the test.

Thermoregulatory sweat test. During this test, you're coated with a powder that changes color when you sweat. While lying in a chamber with slowly increasing temperature, digital photos document the results as you begin to sweat. Your sweat pattern may help confirm a diagnosis of autonomic neuropathy or suggest other causes for decreased or increased sweating.

Urinalysis and bladder function (urodynamic) tests. If you have bladder or urinary symptoms, a series of urine tests can evaluate bladder function.

Ultrasound. If you have bladder symptoms, your doctor may do an ultrasound in which high-frequency sound waves create an image of the bladder and other parts of the urinary tract.

Treatment of autonomic neuropathy includes:

Treating the underlying disease. The first goal of treating autonomic neuropathy is to manage the disease or condition damaging your nerves. For example, if the underlying cause is diabetes, you'll need to tightly control blood sugar to prevent autonomic neuropathy from progressing.

Managing specific symptoms. Some treatments can relieve the symptoms of autonomic neuropathy. Treatment is based on what part of your body is most affected by nerve damage.

Digestive (gastrointestinal) symptoms

Your doctor may recommend:

Modifying your diet. You may need to increase dietary fiber and fluids. Fiber supplements, such as Metamucil or Citrucel, also may help. Slowly increase fiber to avoid gas and bloating.

Medication to help your stomach empty. A prescription drug called metoclopramide (Reglan) helps your stomach empty faster by increasing the contractions of the digestive tract. This medication may cause drowsiness, and its effectiveness wears off over time.

Medications to ease constipation. Over-the-counter laxatives may help ease constipation. Ask your doctor how often you should use these medications. Increasing dietary fiber also may help relieve constipation.

Medications to ease diarrhea. Antibiotics can help treat diarrhea by preventing excess bacterial growth in the intestines. Medications usually used to treat high blood pressure and cholesterol may also be prescribed for managing diarrhea.

Antidepressants. Tricyclic antidepressants, such as imipramine (Tofranil), can help treat nerve-related abdominal pain. Dry mouth and urine retention are possible side effects of these medications.

Urinary symptoms

Your doctor may suggest:

Retraining your bladder. Following a schedule of when to drink fluids and when to urinate can help increase your bladder's capacity and retrain your bladder to empty completely at the appropriate times.

Medication to help empty the bladder. Bethanechol is a medication that helps ensure complete emptying of the bladder. Possible side effects include headache, abdominal cramping, bloating, nausea and flushing.

Urinary assistance (catheterization). During this procedure, a tube is guided through your urethra to empty your bladder.

Sexual dysfunction

For men with erectile dysfunction, your doctor may recommend:

Medications that enable erections. Drugs such as sildenafil (Viagra), vardenafil (Levitra) or tadalafil (Cialis) can help you achieve and maintain an erection. Possible side effects include mild headache, flushing, upset stomach and changes in color vision.

If you have a history of heart disease, arrhythmia, stroke or high blood pressure, use these medications with caution and medical discretion. Also avoid taking these medications if you are taking any type of organic nitrates. Seek immediate medical assistance if you have an erection that lasts longer than four hours.

An external vacuum pump. This device helps pull blood into the penis using a hand pump. A tension ring helps keep the blood in place, maintaining the erection for up to 30 minutes.

For women with sexual symptoms, your doctor may recommend:

Vaginal lubricants. Vaginal lubricants may decrease dryness and make sexual intercourse more comfortable and enjoyable.

Heart rhythm and blood pressure symptoms

Autonomic neuropathy can cause a number of heart rate and blood pressure problems. Your doctor may prescribe:

Medications that help raise your blood pressure. If you feel faint or dizzy when you stand up, your doctor may suggest a drug called fludrocortisone. This medication helps your body retain salt, which helps regulate your blood pressure.

Other drugs that can help raise your blood pressure include midodrine and pyridostigmine (Mestinon). Midodrine may cause high blood pressure when lying down.

Medication that helps regulate your heart rate. A class of medications called beta blockers helps to regulate your heart rate if it goes too high with an activity level.

A high-salt, high-fluid diet. If your blood pressure drops when you stand up, a high-salt, high fluid diet may help maintain your blood pressure. This is generally only recommended for very severe cases of blood pressure problems, as this treatment may cause blood pressure that is too high or swelling of the feet, ankles or legs.

Sweating

If you experience excessive sweating, your doctor may prescribe:

A medication that decreases perspiration. The drug glycopyrrolate (Robinul, Robinul Forte) can decrease sweating. Side effects may include diarrhea, dry mouth, urinary retention, blurred vision, changes in heart rate, headaches, loss of taste and drowsiness. Glycopyrrolate may also increase the risk of heat-related illness (such as heatstroke) from a reduced ability to sweat.

Posture changes. Stand up slowly, in stages, to decrease dizziness. Sit with your legs dangling over the side of the bed for a few minutes before getting out of bed. Flex your feet and grip your hands for a few seconds before standing up, to increase blood flow.

Once standing, try tensing your leg muscles while crossing one leg over the other a few times to increase blood pressure.

Elevate the bed. If you have low blood pressure, it may also help to raise the head of your bed by about 4 inches by placing blocks or risers under the legs at the head of the bed.

Digestion. Eat small, frequent meals to combat digestive problems. Increase fluids, and opt for low-fat, high-fiber foods, which may improve digestion. You may also want to try restricting foods that contain lactose and gluten.

Diabetes management. Try to keep your blood sugar as close to normal as possible. Tight blood sugar control can help lessen symptoms and help to prevent or delay the onset of new problems.

Several alternative medicine treatments may help people with autonomic neuropathy. Remember to discuss any new treatments with your doctor to ensure that they won't interfere with treatments you're already receiving or cause you any harm.

Alpha-lipoic acid

Preliminary research suggests this antioxidant may be helpful in slowing or even reversing neuropathy that's causing blood pressure or heart rate problems, but more study is needed.

Acupuncture

This therapy, which uses numerous thin needles placed in specific points in the body, may help treat slow stomach emptying. More studies are needed to confirm what acupuncture's role is in treating autonomic neuropathy.

Electrical nerve stimulation

Some studies have found that this therapy, which uses low-energy electrical waves transmitted through electrodes placed on the skin, may help ease pain associated with diabetic neuropathy.

Living with a chronic condition presents daily challenges. Some of these suggestions may make it easier for you to cope:

Set priorities. Accomplish the most important tasks, such as paying bills or grocery shopping, and save less important tasks for another day. Stay active, but don't overdo it.

Seek and accept help from friends and family. Having a support system and a positive attitude can help you cope with the challenges you face. Ask for or accept help when you need it. Don't shut yourself off from loved ones.

Talk to a counselor or therapist. Depression and impotence are possible complications of autonomic neuropathy. Seek help from a counselor or therapist in addition to your primary care doctor to discuss possible treatments.

Consider joining a support group. Ask your doctor about support groups in your area. If there isn't a specific group for people with neuropathies, you may find that there's a support group for your underlying condition, such as diabetes.

Some people find it helpful to talk to other people who truly understand what they're going through. Support group members can offer camaraderie, as well as tips or tricks to make living with autonomic neuropathy easier.

While certain inherited diseases that put you at risk of developing autonomic neuropathy can't be prevented, you can slow the onset or progression of symptoms by taking good care of your health in general and managing your medical conditions.

Follow your doctor's advice on healthy living to control diseases and conditions, which may include these recommendations:

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