Neuropathy is caused by damage to the peripheral nerves that link the central nervous system (brain and spinal cord) to the rest of the body. The condition can trigger pain, numbness, tingling, and muscle weakness in any part of the body.
If you suffer from neuropathy, you are not alone. Around 20 million Americans are believed to suffer from neuropathy.
Peripheral nerves carry sensory information from the body, such as pain, temperature, soft touch, and joint position sensation to the central nervous system where your brain receives and interprets the information. The peripheral nerves also communicate information about movement from the central nervous system to the different muscles of the body, enabling you to move your face, vocal cords, and limbs. In addition, nerves carry signals to and from various organs and vessels, controlling important functions such as heart rate and blood pressure.
Neuropathy, and the pain associated with it, can be localized or generalized. Generalized neuropathy can create symptoms in a large part, or even all, of the body. With localized neuropathy, also known as focal neuropathy, a very specific area of the body or nerve is affected.
Because nerves are located all over the body, the pain associated with neuropathy can occur anywhere. Depending on the cause of the neuropathy, and the nerves that are affected, symptoms can vary dramatically.
- You may experience a loss of sensation beginning in your toes that gradually moves up your foot and ankle.
- Sometimes this sensation goes on to affect your fingers and hands. This is typical of a metabolic or toxic neuropathy.
- Individual nerves can also be affected causing numbness or weakness in any limb. This is known as focal neuropathy.
- Carpal tunnel syndrome is a focal neuropathy of a specific nerve in the wrist. Carpal tunnel syndrome can result in numbness and a painful, tingling sensation in the hand.
Muscle weakness and wasting
Some neuropathies damage the "motor" nerves that control the muscles, leading to weakness and muscle wasting. Rare diseases, such as multifocal motor neuropathy and ALS (also known as Lou Gehrig's disease), only affect the motor nerves.
Neuropathy can cause severe, debilitating pain. The pain can vary between a burning or tingling feeling, and an intense, electric shock-like sensation. Intense pain is characteristic of the nerve damage caused by diseases such as shingles.
Screening and Diagnosis
Unless the cause of your symptoms is obvious, such as a recent injury, we will perform a comprehensive history and physical examination to evaluate the timing, progression and nature of your symptoms. We do this to determine if the neuropathy is related to an underlying condition or disease. We can then focus on treating that disorder which, in turn, will treat your neuropathy.
During the examination process, we also look for signs of other medical problems that can mimic the symptoms of neuropathy. For example, a heart attack can cause sensory symptoms in the left arm. Stroke and multiple sclerosis patients can also suffer from numbness and weakness.
Screening for neuropathy usually includes several lab tests. These will include basic blood tests to rule out common disorders, such as diabetes, hypothyroidism, or chronic kidney insufficiency. As neuropathy has many potential causes, we start with tests for conditions or factors that may be indicated by your medical or family history. However in many cases, it is not possible to establish what caused the neuropathy.
The list of potential causes of neuropathy is vast and includes the following basic categories:
Nerves can be damaged by trauma in a number of ways.
- Blunt trauma. This can be caused, for example, by compression of one of the nerves in your wrist as a result of a prolonged bicycle ride.
- Penetrating injuries. These can be caused by a knife wound or, in rare instances, injection injuries.
- Stretch injuries. You can suffer a stretch injury in a motorcycle accident when nerves in the neck and shoulder are stretched, or torn on landing.
- Repetitive use. Repetitive use injuries can damage the nerves as seen in carpal tunnel syndrome (compression of the median nerve in the wrist).
Your metabolism is the chemical process in your body that breaks down food to use as energy. When metabolic processes do not function correctly they can cause nerve damage. This is frequently seen in patients with diabetes, chronic renal failure, hypothyroidism, and a multitude of vitamin deficiencies. In fact, in the US, diabetes is the most common cause of neuropathy.
Many substances are toxic to the nerves, including many medications, environmental and industrial toxins such as lead and other heavy metals, and ingested items such as alcohol.
Many inflammatory or autoimmune disorders can affect the nerves. The most dramatic of these is Guillain-Barre syndrome, where rapidly progressive nerve inflammation can lead to complete paralysis in a few days.
There are a large number of inherited diseases that can cause nerves to develop abnormally or deteriorate. These diseases are seen more often in younger patients.
Some infections that can cause nerve damage, such as leprosy, are rare and not frequently seen in the United States. However more common infections such as HIV, Lyme disease, syphilis, and West Nile virus can also affect the nerves.
Some of the disorders which cause neuropathy may have no specific diagnostic tests to identify them or are not yet well understood. Neuropathy also seems to be part of the aging progress and up to 10 percent of the population over age 60 may experience progressive numbness that affects the feet and toes.
Keep blood sugar under control. Diabetes is one of the most common causes of generalized neuropathy. If you are diabetic, high blood sugar can cause nerve damage, especially in your hands and feet. To prevent diabetic neuropathy we will work with you to make sure you keep your blood sugar consistently under control, get plenty of exercise and monitor your feet for any signs of nerve damage.
Use alcohol in moderation. Alcohol abuse can also be a cause of neuropathy. If you do drink, use alcohol in moderation. Talk to us if you think you have a problem with alcohol.
Avoid repetitive movements. Focal neuropathies, such as carpal tunnel syndrome, can be associated with certain repetitive activities, so we strongly encourage you to pay attention to ergonomics at work. Also try to avoid prolonged repetitive movements.
Medications and Treatments
Neuropathic pain can be a major problem that can interfere with your sleep and normal daily activities. Mild pain can be treated with over-the-counter analgesics such as acetaminophen or ibuprofen. Many of the drugs used to treat neuropathy pain have side effects or may cause serious problems if you combine them with other medications that you are already taking. We will discuss which medications are best for you.
These medications decrease nerve membrane irritability and interrupt pain processing. Side effects include drowsiness and dizziness as well as other, very rare, complications that we will need to monitor. These medications should be taken daily.
Antidepressants control the perception of pain. However, they can also cause drowsiness, as well as dry mouth, constipation, and dizziness. Patients with some types of glaucoma and certain cardiac conditions should avoid these medications. These medications should be taken daily.
We only recommend narcotics for patients who have chronic neuropathic pain that does not respond to any other form of pain relief. Although these drugs provide immediate pain relief, they are habit-forming and their effect decreases over time. They can cause drowsiness, nausea, constipation, and confusion, among other numerous complications.
Topical agents, such as lidocaine, are applied to the skin as an ointment or via a skin patch. These are sometimes effective for localized pain caused by shingles or burning feet. Because they are not taken orally, they do not cause systemic side effects.
Guidelines for Taking Medications
Anticonvulsants and antidepressants
- We will advise you on how to take anticonvulasants and antidepressants.
- These medications need to be taken on a daily basis.
- They may take some time to build up in your system, so don't expect them to work immediately. They should never be used on an as-needed basis.
- We will also advise you to slowly increase the dose over time to minimize the side effects while maximizing the therapeutic benefits.
- If one type of medication doesn't work after you have taken it in this manner, we will often suggest that you try another medication in this class. We may also try a combination of drugs.
Although narcotic medications often provide the best immediate relief for pain, they can be addictive if used on a long-term basis. Tolerance and habituation can be a problem with these medications, so they should not be used for chronic neuropathic pain until other alternatives have been exhausted.
Trans-epidermal nerve stimulation (TENS)
A TENS machine provides low current electrical stimulation through the skin which can control or reduce localized neuropathic pain. Our physical therapists and pain specialists are trained to customize these devices for you.
Some patients experience temporary improvement in neuropathic pain after acupuncture. We can refer you to a member of our complementary and alternative medicine team who is trained to provide acupuncture.
Dorsal column stimulators (DCS)
A DCS is a nerve stimulator that is implanted surgically into the spinal cord. These devices can be helpful in severe cases where nothing else has worked to control pain. Again, we will only recommend this treatment if medication trials have not worked and appropriate specialists, including a neurologist, agrees that DCS is necessary.
An intrathecal pump is a surgically implanted device which infuses pain medication directly into the cerebral spinal fluid surrounding the spinal cord. Like DCS, this is an invasive treatment that is only considered when all medications have been tried and none are effective.
Many patients have symptoms that progress very slowly and are not disabling. However, with most types of generalized neuropathy, particularly those associated with chronic medical conditions like diabetes, the symptoms gradually get worse over time. When motor function is affected, most patients are usually able to continue to walk, although in some cases they may require assistance with braces, canes, or walkers as the neuropathy progresses. If your symptoms are getting worse, let us know immediately so that we can work together to manage them.
Kaiser Permanente has a number of support groups for patients with neuropathy and diabetes. Ask us about them or contact our local Health Education Department for more information.
Some symptoms, including weakness and numbness, can make you vulnerable to falls and other injuries, particularly to the feet. There are some steps you can take to help reduce the risk of injury.
Weakness can cause difficulty with walking, gripping objects, or getting out of bed. We have a team of physical and occupational therapists who can advise you on adapting to these limitations.
For example, muscle weakness in the foot and ankle can cause "foot drop," which prevents you from lifting your foot. A physical therapist can recommend, and fit, ankle braces to prevent this and facilitate walking.
Loss of sensation can make you more susceptible to injuries, particularly in the feet. There are some steps you can take to help reduce the risk of injury:
- Inspect your feet regularly to see if there are cuts or abrasions that you cannot feel because of numbness. These may become infected unless they are treated.
- Wear shoes at all times and keep your house free of clutter to reduce the risk of tripping over, or stepping on, objects.
- Numbness in the feet and/or legs can affect your balance, particularly when walking at night or when your eyes are closed in the shower.
- Place night lights in strategic locations in and around your house, as well as guard rails in the shower and bathroom.
If you have an emergency medical condition, call 911 or go to the nearest hospital.
An emergency medical condition is any of the following:
(1) a medical condition that manifests itself by acute symptoms of sufficient severity (including severe pain) such that you could reasonably expect the absence of immediate medical attention to result in serious jeopardy to your health or body functions or organs; (2) active labor when there isn't enough time for safe transfer to a Plan hospital (or designated hospital) before delivery, or if transfer poses a threat to your (or your unborn child's) health and safety, or (3) a mental disorder that manifests itself by acute symptoms of sufficient severity such that either you are an immediate danger to yourself or others, or you are not immediately able to provide for, or use, food, shelter, or clothing, due to the mental disorder.
This information is not intended to diagnose health problems or to take the place of specific medical advice or care you receive from your physician or other health care professional. If you have persistent health problems, or if you have additional questions, please consult with your doctor. If you have questions or need more information about your medication, please speak to your pharmacist. Kaiser Permanente does not endorse the medications or products mentioned. Any trade names listed are for easy identification only.