What is autonomic neuropathy?
Autonomic neuropathy is also called autonomic dysfunction or dysautonomia. These terms describe many conditions that cause the autonomic nervous system (ANS) not to work. The ANS controls the body functions that we do not consciously think about: breathing, blood pressure regulation, digestion, temperature regulation, and more. Autonomic neuropathy can be a complication of many diseases and conditions and can be a side effect from some medications.
What causes autonomic neuropathy?
There are many underlying diseases and conditions that can lead to autonomic neuropathy. Medication side effects can also be a problem.
Primary causes of autonomic neuropathy include:
- Familial dysautonomia (Riley-Day syndrome)
- Idiopathic orthostatic hypotension (progressive autonomic failure)
- Multiple system atrophy with autonomic failure (Shy-Drager syndrome)
- Parkinson’s syndrome with autonomic failure
Secondary causes of autonomic neuropathy include:
- Amyloidosis (abnormal protein build-up)
- Autoimmune neuropathies (i.e., Guillain-Barre syndrome, myasthenia gravis, rheumatoid arthritis, Sjogren’s syndrome, and systemic lupus erythematosus)
- Carcinomatous autonomic neuropathy (often related to small-cell lung cancer
- Deconditioning (a decrease in function due to inactivity or illness)
- Diabetes and pre-diabetes
- Human immunodeficiency virus (HIV)
- Lyme disease (a disease transmitted by ticks and causing flu-like symptoms)
- Nutritional deficiencies (i.e., vitamins B1, B3, B6, and B12)
- Paraneoplastic syndromes (disorders caused by an immune response to cancer)
- Physical trauma, surgery, pregnancy, or viral illness
- Porphyria (an enzyme disorder that mainly causes skin and/or nerve problems)
- Toxicity (i.e., alcoholism, chemotherapy drugs, and heavy metal poisoning)
- Treatment with medicines, including chemotherapy and anticholinergic drugs
What are the symptoms of autonomic neuropathy?
Common symptoms include:
- Postural hypotension: lightheadedness, dizziness, fainting, dimness of vision, unsteady gait, weakness
- Urinary dysfunction: frequency, excessive urinating at night, urgency, stress incontinence, retention, hesitancy
- Sexual dysfunction: erectile dysfunction, vaginal dryness, decreased libido
- Gastrointestinal dysfunction: intermittent diarrhea, constipation, nausea, vomiting, full-ness after eating little, loss of appetite, slowing of gastric content, bloating, heartburn
- Impaired sweating: excessive or decreased sweating
- Exercise intolerance
- Paresthesias: numbness or tingling in feet, legs, hands, arms or other body parts
Care begins with an accurate diagnosis of the presenting symptoms. This is accomplished by a thorough history and physical examination focused on the autonomic nervous system. Often, special testing of the autonomic nervous system is needed to assist in the diagnosis. The Autonomic Section offers a comprehensive panel of cardiovascular and sudomotor tests to assess the full spectrum of autonomic disorders.
- The Cardiovascular Autonomic Test with Tilt assesses how well a patient’s autonomic nervous system controls blood pressure and heart rate during different maneuvers: deep breathing, the Valsalva maneuver and head-up tilt. These tests are particularly helpful in assessing patients with fainting or syncope.
- The Quantitative Sudomotor Axon Reflex Test (QSART) measures the autonomic nerves that control sweating. This test utilizes a method to stimulate sweat glands and measure the volume of sweat that is produced. The QSART is useful in assessing many autonomic disorders, especially autonomic and small fiber neuropathies as well as some types of pain disorders. The QSART also is helpful in localizing the site of the autonomic disorder to the peripheral or central autonomic nervous system.
- The Thermoregulatory Sweat Test (TST) is a measure of a patient’s ability to sweat when stimulated by a warm and humid environment. This test assesses both the central and peripheral autonomic nervous system’s control of sweating and body temperature regulation (thermoregulation). The pattern of sweating abnormality detected by this test can be helpful in diagnosing a variety of neurological and autonomic disorders that may cause reduced sweating (anhidrosis) or excessive sweating (hyperhidrosis). These disorders include small fiber and autonomic neuropathies, radiculopathies, and central autonomic disorders including multiple system atrophy, Parkinson’s disease with autonomic dysfunction, and pure autonomic failure.
How is autonomic dysfunction treated?
Treating or managing any underlying cause is key. For example, if the underlying cause is diabetes, then controlling blood sugars will be the main treatment. In some cases, treatment of the underlying disease may allow damaged nerves to repair and regenerate. Other treatments are aimed at improving daily quality of life and managing specific symptoms through medications and lifestyle modifications. A combination of approaches is likely to result in the best symptom management.
Specific symptom management
GI symptoms: Certain medications may be prescribed to help empty stomach more rapidly (i.e., Reglan®) or ease constipation (i.e., laxatives). Modify diet by increasing fiber intake.
Urinary symptoms: Retrain the bladder by following a schedule, and/or take medications to help with complete bladder emptying and decrease overactive bladder symptoms (i.e., bethanechol and Ditropan®).
Exercise intolerance: Join a rehabilitation program to ease into a custom exercise routine or begin physical activity at home at a slow rate.
Sexual dysfunction: For men, certain medications may be recommended for erectile dysfunction (i.e. Viagra®, Cialis®). For women, vaginal lubricants may be recommended.
Stress and anxiety: Stress-relieving activities and techniques (i.e. yoga, visualization, massage therapy), as well as certain medications may be recommended (i.e., Celexa®, Effexor®). Numbness and tingling: Certain medications may be recommended to help decrease associated pain (i.e. Neurontin®, Cymbalta®).
Lifestyle changes to improve vascular tone:
- Use physical counter-maneuvers such as leg crossing, leg raising, toe crunching, and lower extremity muscle contracting to increase blood pressure and help pump venous blood back to heart.
- Perform lower extremity exercises daily to improve the strength of the leg muscles. This will help prevent blood from pooling in the legs when standing and walking. Preferred exercises include walking, jogging, swimming, and/or using a stationary bike.
Medications to improve vascular tone:
- Fludrocortisone: improves blood vessel response and causes fluid retention
- Midodrine: produces increase in vascular tone and elevation of blood pressure; has no effect on heart rate
- Beta-blockers: prevent veins from opening excessively and help lower heart rate
- Pyridostigmine: causes blood vessels to constrict which causes slight increase in blood pressure; has no effect on heart rate
Lifestyle changes to improve blood pressure:
- Drink 500ml (16 oz.) of water quickly and all at once, first thing in the morning (before getting out of bed) and when bad symptoms occur. This will result in an increased blood pressure within 5 minutes. The effects should last up to 1 hour and may improve orthostatic intolerance (OI). This condition involves symptoms associated with standing upright and improved by lying down.
- Avoid large meals that can cause low blood pressure during digestion. It is better to eat smaller, more frequent meals throughout the day than to eat three large meals.
- Avoid excessive caffeine intake, as it may increase urine production and reduce blood volume.
Lifestyle changes to improve blood volume:
- Raise the head of your bed by 6-10 inches. The entire bed must be at an angle. Raising only the head portion of the bed at waist level or using pillows will not be effective. Raising the head of the bed will cut urine formation overnight, allowing for more volume in the circulation in the morning. You may use cinder blocks or bed raising kits.
- Drink 2-2.5 liters (about 8.5 to 11 cups) of fluids/day.
- Use custom-fitted elastic support stockings. These will reduce a tendency for blood to pool in legs when you are standing and may improve OI. An abdominal binder or Spanx® may also be useful. Thigh-high stockings are best with some abdominal compression, with pressure of at least 20-30 mmHg (30-40 mmHg pressure is ideal). Put them on first thing in the morning and remove before going to bed.
- Increase the sodium intake in your diet to 3-5 grams/day. If no improvement is noticed and blood pressure remains stable, you may increase sodium intake to 5-7 grams/day. This will help the body retain fluid in the blood vessels to compensate for low blood pressure or excessive pooling of blood in veins. Please note that 1 teaspoon of salt equals 5g and 1/2 teaspoon of salt equals 3g.
|Salty Food Ideas (1000 mg = 1 g)|
|Item||Amount||Mg of salt|
|Green olives||10 medium||529 mg|
|Pretzels||1 cup/15 twists||543 mg to 1,715 mg|
|Beef jerky||1 large piece||443 mg|
|Pumpkin seeds (packaged)||1/4 cup||950 mg|
|Kale chips (packaged) 1 cup||1 cup||431 mg|
|Artichoke hearts||1/2 cup||388 mg|
|Whole dill pickle||1 large pickle||420 mg|
|Broth||1 bouillon cube||1,200 mg|
|Soy sauce||1 teaspoon||335 mg|
|Salami||1 slice||226 mg|
|Sun-dried tomatoes||1 cup||1,047 mg|
|Salt-water crab||1 leg||1,436 mg|
|Cottage cheese (small curd)||1 cup||911 mg|
|V8® drink||12 ounces||690 mg|
|Tomato sauce (canned)||1 cup||1,284 mg|
|Canned green beans||1/2 cup||390 mg|
|Chicken noodle soup||1 cup||720 mg|
|Gatorade® sports drink||8 ounces||110 mg|
|Salt tablet 1 tab 1 g||1 tablet||1 g|
Exercises for autonomic neuropathy to increase blood volume and physical function may be done at home, at the gym, with a physical therapist, or through a local cardiac rehabilitation program, depending on your comfort level and beginning condition. It is best to begin with exercises that do not cause orthostatic stress such as reclined exercises which may include stretches, yoga poses (in seated or lying position), recumbent bicycle, rowing or swimming. Most individuals will begin at level 2, but before beginning any routine it is important to understand your own comfort level as well as determining a starting point with your health care provider.
Reclined gentle movements (level 1)
Leg pillow squeeze: While lying in bed, place pillow between legs and squeeze, hold for 10 sec, rest and repeat.
Arm pillow squeeze: Place pillow folded pillow between palms and squeeze together (like in a praying position), hold for 10 sec, rest and repeat.
Side leg lifts: While lying on your side, lift leg up sideways and then bring leg back down without touching the opposite leg and repeat.
Front leg lifts: While lying on your back, lift leg up, point toes towards ceiling, and repeat.
Recumbent cardio exercises (level 2)
Rowing: Use rowing machine 2-5 minutes per day and increase on weekly basis. Try to reach 45 minutes per day on five days a week.
Swimming: Always swim with a partner or where someone can see you just in case symptoms occur.
Weight training (specifically leg and core muscle training): Begin with light weights and use in reclined or seated position. Try to avoid lifting above head or in any standing position.
Normal exercises (level 3)
Eventually you may get to the point where you are ready to participate in normal upright cardiovascular activities, such as walking, jogging, bicycling and running. Once you get to a good and safe point, you can begin these types of exercises and eventually increase your time to 45 minutes per day three times per week.
Syncope safety instructions
Syncope, also called fainting, is a temporary loss of consciousness due to sudden decline in blood flow to the brain caused by a decrease in blood pressure and heart rate. After an episode, a person quickly “comes to” and is generally “back to normal” fairly quickly. For your own safety and the safety of others around you, mind all of these guidelines for six months following a syncopal event:
- Do not drive.
- Do not take a bath or shower without someone near or within earshot.
- Do not swim alone.
- Do not climb ladders or chairs; avoid heights.
- Do not use power tools or operate heavy machinery.
- Do not take care of young children by yourself.
- Avoid alcohol. Alcohol can cause blood to pool in the legs which may worsen low blood pressure reactions when standing. Get treatment for alcoholism if necessary.
- Avoid heat or environments that tend to trigger symptoms.
- Make postural changes from lying to sitting to standing slowly.
- Keep good control of blood sugars if you have diabetes.
- Seek appropriate treatment and follow instructions for any autoimmune disease you have.
- Take steps to prevent and/or control high blood pressure, including taking any prescribed medications.
- Stop smoking.
- Maintain a healthy weight, and engage in regular exercise.
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