Your peripheral nervous system connects the nerves from the brain and spinal cord (central nervous system) to the rest of the body, including the arms, hands, feet, legs, internal organs, mouth and face. The job of these nerves is to deliver signals about physical sensations back to your brain.
Peripheral neuropathy is a disorder that occurs when these nerves malfunction because they are damaged or destroyed. This disrupts the nerves’ normal functioning. They might send signals of pain when there is nothing causing pain, or they might not send a pain signal even if something is harming you. This can be caused by injury, systemic illness, infection, or may be associated with an inherited disorder.
The disorder is uncomfortable, but treatments can be very helpful. The most important thing to determine is whether peripheral neuropathy is caused by a serious underlying condition.
People who have a family history of peripheral neuropathy are more likely to develop the disorder. However, a variety of factors and underlying conditions may also cause this condition.
Nerve damage caused by diabetes is one of the most common forms of neuropathy. This leads to numbness, pain, and loss of sensation in the extremities. According to the University of Chicago’s Center for Peripheral Neuropathy (UCCPN), nearly 60 percent of diabetics have some sort of nerve damage (UCCPN, 2010). This damage is often due to high blood sugar levels, and risk for neuropathy increases for diabetics who are overweight, have high blood pressure, or are over the age of 40.
Other chronic diseases that may cause nerve damage include:
- kidney disorders in which high amount of toxins build up in the body and damage nerve tissue
- hypothyroidism -- in this disorder, the body doesn’t produce enough thyroid hormone, which can lead to fluid retention and pressure surrounding nerve tissues
- disease that cause chronic inflammation, which can spread to the nerves or damage connective tissue surrounding nerves
- deficiencies of vitamins E, B1, B6, and B12, which are essential to nerve health and functioning, may also cause neuropathy
Physical trauma is the most common cause of injury to the nerves. This can include car accidents, falls, or fractures. Neuropathy can also be caused by inactivity, or holding still too long in one position. Carpal tunnel syndrome is a common type of peripheral neuropathy caused by increased pressure on the median nerve, a nerve in the wrist that supplies feeling and movement to the hand.
Alcohol and Toxins
Alcohol can have a toxic effect on nerve tissue, putting people with severe alcoholism at a higher risk for peripheral neuropathy.
Exposure to toxic chemicals like glue, solvents or insecticides, either through chemical abuse or in the workplace, can also cause nerve damage. Additionally, exposure to heavy metals such as lead and mercury can also cause this condition.
Infections and Autoimmune Disorders
Certain viruses and bacteria directly attack nerve tissue. Viruses such as herpes simplex, varicella-zoster (a virus that causes chickenpox and shingles), and Epstein-Barr damage sensory nerves and cause intense episodes of shooting pain. Bacterial infections such as Lyme disease can also cause nerve damage and pain if untreated.
Autoimmune diseases like HIV/AIDS, rheumatoid arthritis, and lupus all affect the peripheral nervous system in various ways. Chronic inflammation and damage to tissues throughout the body, as well as pressure caused by inflammation, can all lead to severe nerve pain in the extremities.
Certain medications may also cause nerve damage. These include:
- anti-convulsants (drugs used to treat seizures)
- drugs to fight bacterial infections
- some blood pressure medications
- medications used to treat cancer
Recent research in the Journal of Family Practice (JFP) also suggests that statins, a class of drugs used to lower cholesterol and prevent cardiovascular disease, may also cause nerve damage and increase risk for neuropathy. (Coulson, 2011)
There are three types of peripheral nerves:
- sensory nerves, which connect to your skin
- motor nerves, which connect to your muscles
- autonomic nerves, which connect to your internal organs
Peripheral neuropathy can affect one nerve group or all three.
The symptoms of peripheral neuropathy include:
- tingling in hands or feet
- a feeling like you are wearing a tight glove or sock
- sharp, stabbing pains
- numbness in hands or feet
- weak, heavy-feeling arms and legs (sometimes it may feel like your legs or arms “lock” in place)
- regularly dropping things from your hands
- a buzzing or shocking sensation
- thinning of the skin
- a drop in blood pressure
- sexual dysfunction, especially in men
- digestion difficulties
- excessive sweating
These symptoms can also indicate other conditions. Make sure you tell your doctor about all your symptoms.
First, your doctor will perform a physical exam and ask about your medical history. If he or she still can’t tell whether your symptoms are caused by peripheral neuropathy, there are other tests to perform.
Blood tests can measure vitamin and blood sugar levels and determine whether your thyroid is functioning correctly.
Your doctor may also order a computed tomography (CT) scan or magnetic resonance imaging (MRI) to see if anything is pressing on a nerve, such as a herniated disk or a tumor.
Electromyography is a test that can show problems with how your body’s nerve signals are moving through to your muscles. For this test, a small needle is placed into your muscle. The doctor will then ask you to move your muscle gently. Probes in the needle will measure the amount of electricity moving through your muscle. This test may feel like you are receiving a shot. Sometimes, there is soreness in the area for a few days afterward.
In a nerve conduction study, electrodes are placed on your skin. Tiny amounts of electricity are then pulsed through your nerves to see if they are transmitting signals properly. This procedure is slightly uncomfortable while it is happening, but it should not hurt afterward.
Sometimes your doctor will order a nerve biopsy. This is a minor surgery that involves removing a small amount of nerve tissue that can then be examined under a microscope.
If it is caused by an underlying condition that is treatable, you might be able to stop your peripheral neuropathy by treating the larger problem. However, most often peripheral neuropathy can only be managed, not cured.
Many treatments can bring relief and can help you to return to your regular activities. Sometimes a combination of treatments works best.
Over-the-counter pain medications like acetaminophen (Tylenol) and nonsteroidal anti-inflammatory drugs, such as aspirin and ibuprofen, can be very helpful in controlling moderate pain. In excess, these drugs can affect your liver or stomach function, so it is important to avoid using them for an extended period of time, especially if you drink alcohol regularly.
Many prescription pain medications can also help to control the pain of this condition. These include narcotics, some antiepileptic medicines, and some antidepressants. Other helpful prescription medicines include:
- COX-2 inhibitors
- alpha-2 adrenergic agonists
- corticosteroid injections
There are many prescription drugs for sexual dysfunction in men, including:
- sildenafil (Viagra)
- vardenafil (Levitra, Staxyn)
- tadalafil (Cialis)
- avanafil (Stendra)
Research centers and pharmaceutical companies around the world regularly conduct tests of new drugs. Get more information on clinical trials at http://clinicaltrials.gov/.
There are several medical treatments used to control the symptoms of this condition. They are described below.
- Plasmapherisis is a blood transfusion in which potentially irritating antibodies are removed from the patient’s bloodstream.
- A nerve block is an injection of anesthetics directly into the nerves.
- Transcutaneus electronic nerve stimulation (TENS) doesn’t work for everyone, but many patients like it because it is a drug-free therapy. During TENS, electrodes placed on the skin send small amounts of electricity into the skin. This treatment is intended to disrupt nerves from transmitting pain signals to the brain.
- Ergonomic casts can help you if your feet, legs, arms, or hands are affected. These casts provide support for the part of your body that’s uncomfortable. This can relieve pain. For example, the discomfort of carpal tunnel syndrome can be relieved with a cast that holds your wrists in a proper position while you sleep.
In addition to over-the-counter pain relievers, many people have found relief for peripheral neuropathy through chiropractic care, acupuncture (the insertion of tiny needles into key areas), massage, meditation, and yoga. Moderate, regular exercise can also help to lessen discomfort.
If you drink alcohol or smoke, consider cutting back or stopping. Both alcohol and tobacco aggravate nerve pain and can cause nerve damage when used for long periods of time.
Make Your Home Safe
If you have peripheral neuropathy, you are potentially at greater risk for accidents in the home. Remember:
- Always wear shoes to protect your feet.
- Keep your floor clear of things that you could trip on.
- Check the temperature of your bath or dishwater with your elbow, not your hand or foot.
- Consider installing handrails in your bathtub or shower, as well as antislip bath mats.
- Do not stay in one position for too long. Get up and move around a couple times each hour. This is especially important for those whose work involves sitting for long periods at a desk.
Even if you have a family history of this disorder, you can help prevent its onset by doing the following:
- drinking alcohol in moderation, if at all
- avoiding smoking or quitting
- eating a healthy diet
- getting regular, moderate exercise
You can lower the risk of peripheral neuropathy by:
- knowing what toxins you might be exposed to at work or at school
- protecting your feet during sports, especially those that involve kicking
- never inhaling toxins like glue to get high
If you have diabetes, take special care of your feet. Wash and inspect your feet daily, and keep the skin moist with lotion.