An overview plus individual disorder links Peripheral Neuropathy
Peripheral neuropathy is a term used to describe disorders of your peripheral nervous system. Your peripheral nervous system includes nerves in your face, arms, legs, torso, and some nerves in your skull. In fact, all of your nerves not located in your central nervous system — which includes the brain and the spinal cord — are peripheral nerves.
Neuropathies may affect just one nerve (mononeuropathy) or several nerves (polyneuropathy). Your nerves provide communication between your brain and your muscles, skin, internal organs and blood vessels. When damaged, your nerves can’t communicate properly, and that miscommunication causes symptoms such as pain or numbness.
Peripheral neuropathy often affects people with diabetes and autoimmune diseases such as rheumatoid arthritis and lupus. Certain vitamin deficiencies, some medications and alcoholism can also damage peripheral nerves.
Treating the underlying condition may relieve some cases of peripheral neuropathy. In other cases, treatment of peripheral neuropathy may focus on managing pain. Peripheral nerves have a remarkable ability to regenerate themselves, and new treatments for peripheral neuropathy using nerve growth factors or gene therapy may offer even better chances for recovery in the future.
Signs and symptoms
Neurological symptoms may occur related to your central nervous system, which consists of your brain and spinal cord, or your peripheral nervous system, which links your spinal cord and brain to all other parts of your body. The extensive network of peripheral nerves includes the motor nerves, which help your muscles contract, and the sensory nerves, which allow you to feel a range of sensations. In addition, your peripheral nerves help control some of the involuntary functions of the autonomic nervous system, which regulates your internal organs, sweat glands and blood pressure.
Unfortunately, peripheral nerves are fragile and easily damaged. Damage to a peripheral nerve can interfere with the communication between the area it serves and your brain, affecting your ability to move certain muscles or feel normal sensations. Your symptoms will depend on the cause of your neuropathy and on which nerve or nerves are involved.
If a sensory nerve is damaged, you’re likely to experience symptoms that may include:
* Muscle weakness
* Loss of feeling
These symptoms often begin gradually. You may have a tingling sensation or numbness that starts in your toes or the balls of your feet and spreads upward. Tingling might also begin in your hands and extend up your arms. In some cases your skin may become so sensitive that the slightest touch is agonizing. You may also have numbness, or even a complete lack of feeling, in your hands or feet.
At times your symptoms may be barely noticeable, and some people go years without realizing anything is wrong. For others, symptoms are constant, and especially at night may be almost unbearable. Signs and symptoms may include:
* The sensation that you’re wearing an invisible glove or sock
* Burning pain
* Sharp, jabbing or electric-like pain
* Extreme sensitivity to touch, even light touch
* Lack of coordination
If your motor nerves are affected, you may have weakness or paralysis of the muscles controlled by those nerves. And if you have damage to nerves that control certain functions of the autonomic nervous system, you might have bowel or bladder problems, reduced sweating or impotence. You might also experience a sharp fall in your blood pressure when you stand up, which may cause you to faint or feel lightheaded.
Illustration showing nerve damage in Guillain-Barre syndrome Nerve damage in Guillain-Barre syndrome
A number of factors can cause neuropathies. When a single nerve is affected, the most likely cause is trauma or some type of repetitive use that puts pressure on the nerve. Nerve pressure can result from using a cast or crutches, spending a long time in an unnatural position — such as typing at a computer keyboard — or having a tumor or abnormal bone growth.
When damage occurs to several nerves, the cause frequently is diabetes. At least half of all people with diabetes develop some type of neuropathy. Other common causes include alcoholism, HIV/AIDS, inherited disorders, amyloidosis and a deficiency of certain vitamins, especially B vitamins.
Other causes of peripheral nerve damage may include:
* Other diseases. These include autoimmune diseases, such as lupus and rheumatoid arthritis, kidney disease, liver disease and an underactive thyroid (hypothyroidism).
* Exposure to poisons. These may include some toxic substances and certain medications — especially those used to treat cancer.
* Genetic makeup. You may inherit a tendency to develop peripheral neuropathy.
* Bacterial or viral infections. An acute condition called Guillain-Barre syndrome frequently causes severe damage to all or part of your peripheral nerves by destroying the myelin sheath that covers nerve fibers. The myelin sheath acts as an insulator for your nerves and helps conduct nerve impulses. Although the exact cause of Guillain-Barre syndrome isn’t known, most cases occur after an infection, surgery or immunization.
Unfortunately, it’s not always easy to pinpoint the cause of peripheral neuropathy. In fact, if your neuropathy isn’t associated with diabetes, it’s possible the cause may never be found.
Having diabetes places you at high risk of developing peripheral nerve damage. In fact, at least half of people with diabetes have some form of neuropathy. The risk increases the longer you have diabetes, and is highest for those who’ve had the disease for more than 25 years. Your risk is even greater if you are older than 40 or have difficulty controlling your blood sugar level.
Although researchers don’t understand exactly how damage occurs, a high blood sugar level seems to impair your nerves’ ability to transmit signals. You can help reduce your risk by carefully following a medically approved plan for keeping your blood sugar level as close to normal as possible.
Your risk of developing peripheral neuropathy is also higher if you have one or more of the following risk factors:
* Alcohol abuse. Excessive drinking of alcohol can affect your nervous system, causing numbness of your hands and feet.
* Vitamin deficiency. A lack of certain vitamins, especially B-1 (thiamin) and B-12 makes peripheral neuropathy more likely. Pernicious anemia, which occurs when your body can’t absorb B-12 properly, often leads to peripheral neuropathy.
* Immune system disorders. You’re more likely to develop peripheral neuropathy if you have an autoimmune disease, such as lupus or rheumatoid arthritis, or if your immune system is compromised by the human immunodeficiency virus (HIV) or AIDS.
* Other health problems. Medical conditions, including certain types of cancer, kidney disease and liver disease, also can put you at risk of nerve damage.
* Repetitive stress. A job or hobby that puts stress on one nerve for long periods of time increases your chances of developing peripheral neuropathy. In carpal tunnel syndrome, for example, the median nerve that extends through your wrist into your fingers becomes compressed. Repetitive assembly line work or work involving prolonged, heavy gripping can compress the median nerve. Playing golf, tennis or a musical instrument and using vibrating power tools or even crutches also can put pressure on peripheral nerves.
* Toxic substances. Exposure to some toxic substances can make you susceptible to peripheral nerve damage. These substances include heavy metals, such as lead, mercury and arsenic; organic solvents; and certain medications, such as those used to treat cancer or AIDS.
When to seek medical advice
See your doctor regularly if you have diabetes, a compromised immune system or any other chronic medical condition.
If you have a cut or sore on your foot that doesn’t seem to be healing, is infected or is getting worse, see your doctor promptly, especially if you have diabetes. Even minor sores that don’t heal can turn into ulcers. In the most severe cases, untreated foot ulcers may become gangrenous — a condition in which the tissue dies — and require surgery or even amputation of your foot.
Seek medical care right away if you notice any unusual tingling, weakness or pain in your hands or feet. Early diagnosis and treatment offers the best chance for controlling your symptoms and preventing further damage to your peripheral nerves. If your symptoms are interfering with your sleep or you feel depressed, your doctor or pain specialist may be able to suggest treatments that can help.
Screening and diagnosis
Peripheral neuropathy isn’t a single disease, but rather a syndrome with many causes. For that reason it can be difficult to diagnose. To help in the diagnosis, your doctor will likely take a full medical history and perform a physical and neurological exam that may include checking your tendon reflexes, your muscle strength and tone, your ability to feel certain sensations, and your posture and coordination.
Your doctor may also request blood tests to check your level of vitamin B-12, a urinalysis, thyroid function tests and, often, electromyography (EMG) — a test that measures the electrical discharges produced in your muscles. As a part of this test, you’ll be asked to have a nerve conduction study, which measures how quickly your nerves carry electrical signals. A nerve conduction study is often used to diagnose carpal tunnel syndrome and other peripheral nerve disorders.
Your doctor may recommend a nerve biopsy, a procedure in which a small portion of a nerve is removed and examined for abnormalities. But even a nerve biopsy may not always reveal what’s damaging your nerves.
Diabetic neuropathy may cause a number of complications. Damage to the nerves in your feet, along with poor circulation, can lead to ulcers and even gangrene. But it’s not only your feet that are vulnerable — diabetes-related neuropathy can affect any organ in your body.
If nerves related to digestion are damaged, for instance, your stomach may empty too slowly, which may cause constant nausea, vomiting and bloating. Or you may have frequent constipation or diarrhea. In some cases you may have problems with bladder control or impotence.
Other complications include:
* Partial or complete loss of movement or sensation
* Low blood pressure
* Weight loss
Photo of TENS unit being applied TENS
The goal of treatment is to manage the underlying condition causing your neuropathy and repair damage, as well as provide symptom relief. If your doctor hasn’t been able to determine the cause of your neuropathy, he or she may try a variety of medications to see which help ease your symptoms.
Controlling a chronic condition may not eliminate your neuropathy, but it can play a key role in managing it. Here’s what your doctor may recommend for treating various underlying conditions:
* Diabetes. If you have diabetes, you and your doctor can work together to keep your blood sugar level as close to normal as possible. Maintaining normal blood sugar levels helps protect your nerves, though your symptoms may initially get worse before they begin to improve.
* Vitamin deficiency. If your neuropathy is the result of a vitamin deficiency, it’s likely your symptoms will improve once the deficiency is corrected. Your doctor may recommend injections of vitamin B-12 daily for a few days, then once a month. If you have pernicious anemia, you’ll need regular injections for the rest of your life, and possibly additional vitamin supplements. You’ll also need to eat a healthy diet.
* Autoimmune disorder. If your neuropathy is caused by an inflammatory or autoimmune process, treatment will be aimed at controlling your immune response.
* Nerve pressure. In cases where neuropathy is the result of pressure on a nerve, treatment will likely focus first on eliminating the source of the pressure. That might mean adding ergonomic chairs, desks or keyboards to your home or office, changing the way you hold tools or instruments, or taking a break from certain hobbies or sports. In some cases of nerve compression, you may need surgery to correct the problem.
* Toxic substances or medications. If toxins or medications are responsible for the neuropathy, it’s critical that you stop taking the medication or avoid further exposure to the toxin to prevent the neuropathy from progressing further.
Medications can ease pain symptoms, but most have side effects, especially if you take them for long periods of time. If you take pain medication regularly, including over-the-counter (OTC) products, discuss the benefits and side effects with your doctor. Medications that may help provide pain relief for neuropathy include:
* Pain relievers. OTC pain relievers, such as acetaminophen (Tylenol, others), and nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin and ibuprofen (Advil, Motrin, others), usually help mild symptoms. For more severe symptoms, your doctor may recommend prescription NSAIDs. If you take NSAIDs for long periods of time or in large doses, you may develop nausea, stomach pain, bleeding or even ulcers.
* Anti-seizure medications. Drugs such as gabapentin (Neurontin), carbamazepine (Tegretol) and phenytoin (Dilantin) were originally developed to treat seizure disorders (epilepsy). However, doctors often also prescribe them for jabbing pain. Side effects may include drowsiness and dizziness.
* Lidocaine patch. This patch contains the topical anesthetic lidocaine. You apply it to the area where your pain is most severe, and you can use up to three patches a day to relieve pain. This treatment has almost no side effects except, for some people, a rash at the site of the patch.
* Tricyclic antidepressants. Antidepressant medications, such as amitriptyline, nortriptyline (Pamelor), desipramine (Norpramin) and imipramine (Tofranil), may provide relief for mild to moderate symptoms by interfering with chemical processes in your brain that cause you to feel pain. Common side effects of these medications may include balance problems, dry mouth, nausea, tiredness, constipation and weight gain. To help reduce these side effects, your doctor will likely start you off at a low dose and slowly increase the amount of drug you take. If you’re bothered by insomnia, your doctor may also recommend an antidepressant or a sleeping medication. Some studies have also suggested that selective serotonin reuptake inhibitors (SSRIs), such as paroxetine (Paxil) and fluoxetine hydrochloride (Prozac), may help relieve the signs and symptoms of peripheral neuropathy.
* Other medications. Opioid analgesics, such as codeine or oxycodone (OxyContin) may be used to relieve pain. However, this class of medications produces numerous side effects, including addiction, that make long-term use of these drugs undesirable. Mexiletine (Mexitil), a drug ordinarily used to treat irregular heart rhythms, sometimes helps relieve burning pain.
Research aimed at finding more effective treatments for peripheral neuropathy is ongoing. For example, researchers are looking at developing nerve growth factors to reproduce the chemicals that signal your body to repair small nerve fibers. Unfortunately, no medications can repair nerve damage yet, but the body can regenerate nerves if the offending substance is removed.
Several drug-free therapies and techniques may also help with pain relief. Doctors frequently use them in conjunction with medications, but some may be effective on their own. They include:
* Transcutaneous electrical nerve stimulation (TENS). Your doctor may prescribe this therapy, which may help prevent pain signals from reaching your brain. TENS delivers tiny electrical impulses to specific nerve pathways through small electrodes placed on your skin. Although safe and painless, TENS doesn’t work for everyone or for all types of pain.
* Biofeedback. This therapy uses a special machine to teach you how to control certain body responses that reduce pain. You then learn how to control these same responses yourself. Biofeedback techniques are often taught in medical centers and hospitals.
* Acupuncture. The National Institutes of Health has found that acupuncture can be an effective treatment for chronic pain, possibly including the pain of neuropathy. Keep in mind that you may not get immediate relief with acupuncture and may require more than one session.
* Hypnosis. Many adults can be hypnotized by a trained professional, but for hypnosis to be most effective, you also have to be a willing and motivated participant. During hypnosis, you’ll typically receive suggestions intended to decrease your perception of pain.
* Relaxation techniques. Designed to help reduce the muscle tension that makes pain worse, relaxation techniques range from deep-breathing exercises to visualization (imagining yourself floating in a tropical ocean, for example), yoga and meditation. You might want to take classes in one or more of these techniques, or you can learn them yourself using books or tapes.
The best way to prevent peripheral neuropathy is to carefully manage any medical condition that puts you at risk. That means controlling your blood sugar level if you have diabetes or talking to your doctor about safe and effective treatments if you think you may have a problem with alcohol.
Whether or not you have a medical condition, eat a healthy diet that’s rich in fruits, vegetables, whole grains and lean protein. The best food sources of vitamin B-12 are meats, fish, eggs, low-fat dairy foods and fortified cereals. If you’re a strict vegetarian, fortified cereals are a good source of vitamin B-12 for you, but you may also want to talk to your doctor about B-12 supplements.
As much as possible, avoid repetitive motions, cramped positions and toxic chemicals, all of which may cause nerve damage.
The following suggestions can help you manage peripheral neuropathy:
* Take care of your feet, especially if you have diabetes. Check your feet daily for signs of blisters, cuts or calluses. Tight shoes and socks can worsen pain and tingling and may lead to sores that won’t heal. Wear soft, loose cotton socks and padded shoes. You can use a semicircular hoop, which is available in medical supply stores, to keep bedcovers off hot or sensitive feet.
* Exercise. Ask your doctor about an exercise routine that’s right for you. Regular exercise may reduce neuropathy pain and can help control blood sugar levels.
* Quit smoking. Cigarette smoking can affect circulation, increasing the risk of foot problems and possibly amputation.
* Eat healthy meals. If you’re at high risk of neuropathy or have a chronic medical condition, healthy eating is especially important. Emphasize low-fat meats and dairy products and include lots of fruits, vegetables and whole grains in your diet. Drink alcohol in moderation.
* Massage your hands and feet, or have someone massage them for you. Massage helps improve circulation, stimulates nerves and may temporarily relieve pain.
* Avoid prolonged pressure. Don’t keep your knees crossed or lean on your elbows for long periods of time. Doing so may cause new nerve damage.
Living with chronic pain or disability presents daily challenges. Some of these suggestions may make it easier for you to cope:
* Set priorities. Decide which tasks you need to do on a given day, such as paying bills or shopping for groceries, and which can wait until another time. Stay active, but don’t overdo.
* Get out of the house. When you have severe pain, it’s natural to want to be alone. But this only makes it easier to focus on your pain. Instead, visit a friend, go to a movie or take a walk.
* Seek and accept support. It isn’t a sign of weakness to ask for or accept help when you need it. In addition to support from family and friends, consider joining a chronic pain support group. Although support groups aren’t for everyone, they can be good places to hear about coping techniques or treatments that have worked for others. You’ll also meet people who understand what you’re going through. To find a support group in your community, check with your doctor, a nurse or the county health department.
* Prepare for challenging situations. If something especially stressful is coming up in your life, such as a move or a new job, knowing what you have to do ahead of time can help you cope.
* Talk to a counselor or therapist. Insomnia, depression and impotence are possible complications of peripheral neuropathy. If you experience any of these, you may find it helpful to talk to a counselor or therapist in addition to your primary care doctor. There are treatments that can help.
Specific type of PN:
http://tinyurl.com/4fxyu (Mayo Clinic)