An Overview of Peripheral Neuropathy

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Peripheral nerves are thin structures located in your arms, legs and throughout your body. When one or more of these nerves become damaged (as a result of an underlying disease process, medication, or infection, to name a few), a condition called peripheral neuropathy develops.

The diagnosis of peripheral neuropathy requires a careful and thorough medical history and neurological examination. Various blood or nerve-related tests are also often required. For the treatment of peripheral neuropathy, a doctor will address the underlying cause behind the neuropathy, as well as prescribe medication(s) to ease symptoms like numbness, tingling, and pain.

Causes

Most of the time when you hear the word "peripheral neuropathy," the person is referring to a "polyneuropathy," which means that multiple peripheral nerves are damaged.

Polyneuropathy

There are many different causes of polyneuropathy, with some of the most common ones being:

Medications, especially various chemotherapies, are also potential culprits of peripheral neuropathy, as is heavy metal exposure, HIV infection, kidney failure, chronic liver disease and rarely, inherited diseases, like Charcot-Marie-Tooth disease.

One of the most severe types of polyneuropathy is Guillan Barre Syndrome, also called acute demyelinating polyneuropathy. This dangerous disease is characterized by a quickly progressive tingling and weakness, usually beginning in the feet, with rapidly ascending weakness of the legs. Eventually, weakness of the muscles that control breathing occurs.

Mononeuropathy

There are also localized types of peripheral neuropathies, called mononeuropathies. Mononeuropathy means that a single peripheral nerve is damaged, usually as a result of trauma, compression, or entrapment. The most classic example of a mononeuropathy is carpal tunnel syndrome, which refers to compression of the median nerve, causing numbness and tingling in the wrist.

Symptoms and Signs

Specific symptoms and signs related to a peripheral neuropathy depend on many factors, most notably the type of peripheral nerve that is affected—sensory (most common), motor, autonomic, or some combination.

Sensory

Sensory nerves receive input from various locations of the body. They then send messages to the brain about the body’s sensations, such as hot and cold, pain, and touch.

When sensory nerves are damaged, one or more of the following symptoms or signs may occur:

  • Lack of sensation to pain changes in temperature
  • Unusual sensations like vibration, numbness and tingling, burning, stabbing, electrical, or crawling
  • Pain from a light touch that is normally painless (called allodynia)
  • Loss of position sense and balance problems
  • Change in temperature

Diabetic polyneuropathy is a classic example of predominantly sensory nerve damage (in this case, from high blood sugar levels). Symptoms usually begin in the toes and feet (on both sides of the body) and may include numbness, prickling, tingling, burning, and pain that is worse at night. Extreme sensitivity to light touch also usually occurs.

As the disease progresses, the symptoms begin to move up the legs. Generally speaking, once the symptoms are felt in the mid-calves, hand symptoms may beging to develop.

Motor

Motor nerves transmit messages from the brain and spinal cord, telling various muscles to move. When motor nerves are damaged, the most common symptom is muscle weakness.

Other symptoms and signs may include:

  • Muscle cramping and shrinking
  • Fasciculations (when a muscle twitches without your control)
  • Reflex abnormalities

Autonomic

Autonomic nerves regulates how your internal organs, such as your blood vessels, stomach, heart, and sweat glands, function.

Common symptoms and signs of autonomic nerve damage include:

Keep in mind, the symptoms of peripheral neuropathy can range in intensity from mildly bothersome to severe and disabling and develop gradually over years, or in some cases, over days.

Diagnosis

The diagnosis of peripheral neuropathy begins with a neurological examination.

Neurological Examination

During the exam, your doctor will check your reflexes, and evaluate for various sensation disturbances (vibration, temperature, and pinprick) on your body, especially on your feet and hands. Your doctor will also evaluate your muscle strength and your gait.

Blood Tests

In order to sort out the root cause of your peripheral neuropathy, your doctor will order a series of blood tests, with some of the most common ones being:

Additional blood tests like, for example, genetic testing for Charcot-Marie-Tooth disease or an HIV antibody test for HIV infection, may also be ordered based on your doctor's underlying suspicion.

Nerve-Specific Tests

In some cases, a nerve conduction velocity study (NCV) and electromyography (EMG) are used to confirm a diagnosis of peripheral neuropathy.

Likewise, sometimes a nerve biopsy (when a sample of nerve tissue is removed and examined under a microscope) or a neurodignostic skin biopsy (when a tiny piece of skin containing nerve fiber endings is removed and examined under a microscope) may be performed.

Autonomic Tests

For peripheral neuropathies with autonomic symptoms, various autonomic tests may be helpful in the diagnostic process, such as measuring a person's heart rate response to tilt (to check for orthostatic hypotention) or tests of sweat function.

Other Tests

Besides various blood and nerve-related tests, sometimes other tests are needed to determine or help confirm the cause of a person's peripheral neuropathy.

For instance, a cerebrospinal fluid analysis via a lumbar puncture (spinal tap) may be performed to support a diagnose of Guillain-Barre syndrome. A twenty-four urine collection may be ordered for possible heavy metal exposure.

Differential Diagnoses

It's important to note that during the diagnostic process for peripheral neuropathy, your doctor will want to ensure that your symptoms are not due to a condition of the central nervous system (CNS), which is comprised of your brain and spinal cord. CNS conditions that may mimic various peripheral neuropathies include stroke and multiple sclerosis (MS).

The good news is that a careful medical history and neurological exam can usually distinguish central from peripheral nervous system conditions. For example, brisk reflexes and spastic muscles (tight, stiff muscles) may be seen with a central nervous system disease, like MS, but not with peripheral neuropathy.

Likewise, with a stroke, which is caused by inadequate blood flow in the brain, symptoms usually occur suddenly, as opposed to the symptoms of peripheral neuropathy, which develop over a longer period of time.

Treatment

The treatment of peripheral neuropathy requires two main steps—addressing the underlying cause and easing symptoms.

Tackle the Underlying Cause

Tackling the "why" behind your peripheral neuropathy is a critical first step.

For example, if a person's neuropathy is occurring as a result of diabetes, then obtaining better and tight control of glucose (sugar) levels may help preserve nerve function. Likewise, if a nutritional deficiency is the neuropathy culprit, then correcting it, should help the neuropathy.

For medication or toxin-induced neuropathies, removing the offending agent or lowering/altering the dose may be recommended.

For other types of neuropathy, more urgent, invasive treatments are required. For example, with Guillain-Barre syndrome, people usually required hospitalization and treatment with intravenous immunoglobulin or plasmapheresis in order to improve symptoms and shorten the disease course.

Soothing Symptoms

Several medications are available to help ease the symptoms of peripheral neuropathy, such as numbness and pain.

Examples of such medications include:

Analgesics like tramadol or various opioids or complementary therapies, like acupuncture, may also be added on for pain control.

In addition to medication, physical therapy and the use of walking assistive devices can help people with neuropathy-related weakness or balance problems. Regular foot care by a podiatrist to prevent the development of foot ulcers and infections are also an important part of the treatment plan, especially for those with diabetic neuropathy.

A Word From Verywell

Peripheral neuropathy is a fairly common condition with a variety of causes. If you or a loved one has been diagnosed with peripheral neuropathy, please be at ease knowing that there are a number of medical treatments that can help reduce pain and discomfort. Additionally, treatments tailored to the root cause of your neuropathy can help prevent your neuropathy from getting worse and in some cases, reverse it.

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