Autonomic Neuropathy



Introduction

Neuropathy is the term for damage to your nerves. Autonomic neuropathy is damage to the nerves that regulate the body functions that you can't control, including the nerves that regulate your heart rate, blood pressure, perspiration and digestion, among other functions. Neuropathies are often due to diabetes, although they also have other causes.

Your nerves transmit messages between your brain and your muscles, blood vessels, skin and internal organs. Autonomic neuropathy results in faulty communication between your brain and the parts of your body that your autonomic nervous system serves.

Signs and symptoms of autonomic neuropathy vary depending on which nerves are affected but can range from dizziness to trouble with digestion and urination to sexual difficulties. Treatment of autonomic neuropathy involves addressing the underlying cause, if possible, and managing the signs and symptoms.

Signs and symptoms

Signs and symptoms of autonomic neuropathy depend on which parts of your autonomic nervous system are most affected. They may include:
  • A drop in blood pressure on standing (orthostatic hypotension), which can cause dizziness and fainting
  • Trouble with urination, including diminished sensation, overflow incontinence and inability to empty your bladder completely, which can lead to urinary tract infections
  • Sexual difficulties, including impotence in men, and vaginal dryness and difficulties with arousal and orgasm in women
  • Difficulty digesting food (gastroparesis), which can cause a feeling of fullness after eating little, loss of appetite, diarrhea, constipation, abdominal bloating, nausea, vomiting and heartburn
  • Cardiovascular problems, such as heart rate abnormalities that may include a lack of normal heart rate changes when you exert yourself
  • Heat intolerance, especially during exercise, and abnormal — usually decreased — sweating
  • Sluggish pupil reaction to light and dark
  • Exercise intolerance, which causes your heart rate to remain unchanged instead of increasing and decreasing in response to your activity level
  • Lack of usual warning signs of low blood sugar (hypoglycemia), which include shakiness, sweating and palpitations
Causes

Your nervous system is made up of two parts. The core is your central nervous system — your brain and spinal cord. The rest of your nervous system, branching off from your spinal cord to the rest of your body, is your peripheral nervous system.

Part of the peripheral nervous system involves nerves that you consciously control — such as nerves you use to move your voluntary muscles. Part is your autonomic nervous system — the nerves that regulate the part of your nervous system that you can't control, such as your heart rate, blood pressure and intestinal function.

Damage to your peripheral nerves is called peripheral neuropathy. Autonomic neuropathy is a type of peripheral neuropathy.

A number of conditions can lead to damage of the autonomic nerves. The most common cause is diabetes. About half the people who have diabetes eventually develop some type of neuropathy.

Other causes may include:
  • Alcoholism, a chronic, progressive disease that can lead to nerve damage
  • 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
  • Some tumors, which can press on nerves and cause direct or remote damage (paraneoplastic syndrome)
  • Multiple system atrophy, a degenerative disorder that destroys the nervous system
  • Surgical or traumatic injury to nerves
  • Treatment with certain medications, including some chemotherapy drugs and anticholinergics
  • Other chronic illnesses, such as Parkinson's disease and HIV/AIDS
Treatment

Treatment for autonomic neuropathy depends on the underlying cause and the particular signs and symptoms you're experiencing. For example, if the underlying cause is diabetes, you'll need to control your blood sugar to keep it as close to normal as possible. If the underlying cause is an autoimmune disease, treatment will focus on modulating your immune system and decreasing inflammation.

The goal of treatment is to manage the underlying condition, repair nerve damage, if possible, and provide symptom relief.

Medications
The type of medication your doctor may prescribe depends on your symptoms.
  • Gastrointestinal symptoms. Your doctor may prescribe metoclopramide (Reglan, Metoclopramide HCL), which helps your stomach empty more rapidly by increasing the contractions of the stomach and intestines. Possible side effects include diarrhea when taken in high doses, drowsiness and restlessness. Other medications include fiber supplements to relieve constipation and tricyclic antidepressants for diarrhea and abdominal pain. Possible side effects of tricyclic antidepressants include orthostatic hypotension, drowsiness, urinary retention, constipation and dry mouth.
  • Sexual dysfunction. Your doctor may prescribe sildenafil (Viagra), vardenafil (Levitra) or tadalafil (Cialis) for erectile dysfunction. Possible side effects include flushing, indigestion and headache. Don't take these medications if you've had a heart attack, stroke or life-threatening heart rhythm in the previous six months. Treatments for vaginal dryness include vaginal estrogen cream (Premarin, Estrace), which you insert into your vagina with an applicator two or three times a week, and vaginal estrogen rings (Estring), which release estrogen for 90 days.
  • Bladder problems. Bethanechol (Urecholine) helps improve urination and emptying of the bladder. Possible side effects include dizziness, lightheadedness or fainting. The anticholinergic medications tolterodine (Detrol) and oxybutynin (Ditropan) calm an overactive bladder. You may experience dry mouth when taking anticholinergics. Your doctor also may prescribe an antibiotic to clear up a urinary tract infection.
  • Postural hypotension. If you get dizzy or feel faint from a drop in blood pressure when you get up, your doctor may prescribe medication, a high-salt diet or support stockings. He or she may prescribe fludrocortisone acetate (Florinef) to help your body retain salt or recommend a blood pressure regulator such as midodrine (ProAmatine). Possible side effects of midodrine include blurred vision, headache and pounding in the ears. Recently, pyridostigmine (Mestinon) has shown promising results for treating postural hypotension without causing high blood pressure when lying down (supine hypertension), a common problem with midodrine.
  • Sweating. If autonomic neuropathy affects sweating, it usually causes a decrease. But if you experience excessive sweating, your doctor may prescribe a drug that inhibits sweating, such as glycopyrrolate (Robinul, Robinul-Forte) or clonidine (Catapres).
Therapies and procedures
If you have trouble emptying your bladder fully, your doctor may recommend intermittent urinary catheterization, a procedure in which a tube is threaded through your urethra to empty your bladder. Psychotherapy or counseling may be appropriate if you're depressed. Sex therapy or couples counseling might be helpful if you're experiencing relationship problems as a result of sexual dysfunction.

Prevention

Taking good care of your health in general and managing any medical condition that puts you at risk of autonomic neuropathy is the best prevention. Unfortunately, however, there's no way to prevent degenerative diseases, such as multiple system atrophy, that increase the risk of developing autonomic neuropathy. Ways to help prevent autonomic neuropathy may include:
  • Control your blood sugar if you have diabetes.
  • Get help if you have a problem with alcohol.
  • Get appropriate treatment if you have an autoimmune disease.
  • Take steps to prevent or control high blood pressure.
  • Achieve and maintain a healthy weight.
  • Stop smoking.
  • Exercise regularly.


Credit: National Institute of Health.
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