The body’s nervous system is made up of two parts. The central nervous system (CNS) includes the brain and the spinal cord. The peripheral nervous system (PNS) connects the nerves running from the brain and spinal cord to the rest of the body…the arms and hands, legs and feet, internal organs, joints and even the mouth, eyes, ears, nose, and skin.

Peripheral neuropathy occurs when nerves are damaged or destroyed and can’t send messages from the brain and spinal cord to the muscles, skin and other parts of the body. Peripheral neuropathies can present in a variety of forms and follow different patterns. Symptoms may be experienced over a period of days, weeks, or years. They can be acute or chronic.

In acute neuropathies such as Guillain-Barre syndrome (in which the body’s immune system attacks part of the peripheral nervous system and impairs sending and receiving nerve signals), symptoms appear suddenly, progress rapidly, and resolve slowly as damaged nerves heal. In chronic forms, symptoms begin subtly and progress slowly. Some people may have periods of relief followed by relapse. Others may reach a plateau stage where symptoms stay the same for many months or years. Many chronic neuropathies worsen over time. Although neuropathy may be painful and potentially debilitating, very few forms are fatal.

In diabetic neuropathy, one of the most common forms of peripheral neuropathy, nerve damage occurs in an ascending pattern. The first nerve fibres to malfunction are the ones that travel the furthest from the brain and the spinal cord. Pain and numbness often are felt symmetrically in both feet followed by a gradual progression up both legs. Later, the fingers, hands, and arms may become affected.

Signs and symptoms of peripheral neuropathy might include:
Gradual onset of numbness, prickling or tingling in your feet or hands, which can spread upward into your legs and arms
Sharp, jabbing, throbbing, freezing or burning pain
Extreme sensitivity to touch
Lack of coordination and falling
If autonomic nerves are affected, signs and symptoms might include:
Heat intolerance and altered sweating

 

Causes

  • Alcoholism. Poor dietary choices made by people with alcoholism can lead to vitamin deficiencies.
  • Autoimmune diseases. These include Sjogren’s syndrome, lupus, rheumatoid arthritis, Guillain-Barre syndrome, chronic inflammatory demyelinating polyneuropathy and necrotizing vasculitis.
  • Diabetes. More than half the people with diabetes develop some type of neuropathy.
  • Exposure to poisons such as lead, mercury, and arsenic can cause peripheral neuropathy. In addition, certain insecticides and solvents have also been known to cause neuropathies.
  • Medications. Certain medications, especially those used to treat cancer (chemotherapy), can cause peripheral neuropathy.
  • Infections. These include certain viral or bacterial infections, including Lyme disease, shingles, Epstein-Barr virus, hepatitis C, leprosy, diphtheria and HIV.
  • Small vessel disease can decrease oxygen supply to the peripheral nerves and lead to serious nerve tissue damage. Diabetes frequently leads to impaired blood flow to nerves. Various forms of vasculitis (blood vessel inflammation) frequently cause vessel walls to harden, thicken, and develop scar tissue, decreasing their diameter and impeding blood flow. Vasculitis is an example of nerve damage called mononeuritis multiplex or multifocal mononeuropathy, in which isolated nerves in two or more areas are damaged.
  • Inherited disorders. Disorders such as Charcot-Marie-Tooth disease are hereditary types of neuropathy.
  • Trauma or pressure on the nerve. Traumas, such as from motor vehicle accidents, falls or sports injuries, can sever or damage peripheral nerves. Nerve pressure can result from having a cast or using crutches or repeating a motion such as typing many times.
  • Tumours, Growths, cancerous (malignant) and noncancerous (benign), can develop on the nerves or press nerves. Also, polyneuropathy can arise as a result of some cancers related to the body’s immune response. These are a form of paraneoplastic syndrome.
  • Vitamin deficiencies. B vitamins — including B-1, B-6 and B-12 — vitamin E and niacin are crucial to nerve health.
  • Bone marrow disorders. These include abnormal protein in the blood (monoclonal gammopathies), a form of bone cancer (osteosclerotic myeloma), lymphoma and amyloidosis.
  • Kidney disorders may cause neuropathies. Kidney dysfunction can lead to abnormally high amounts of toxic substances in the blood that can damage nerve tissue. A majority of individuals who require dialysis because of kidney failure develop polyneuropathy.
  • Other diseases. These include liver disease, connective tissue disorders and an underactive thyroid (hypothyroidism).
  • In a number of cases, no cause can be identified (idiopathic).

Diagnosis

A thorough neurological examination is required to sort out the cause of the symptoms and involves taking an extensive medical history (covering symptoms, work environment, social habits, exposure to toxins, alcohol use, and risk of HIV or other infectious diseases, and family history of neurological diseases).

A physical examination and various tests may reveal the presence of a systemic disease causing the nerve damage. Tests of muscle strength, as well as evidence of cramps or fasciculation’s, indicate motor fibre involvement. Evaluation of the person’s ability to sense vibration, light touch, body position, temperature, and pain reveals any sensory nerve damage and may indicate whether small or large sensory nerve fibres are affected.

Blood tests can detect diabetes, vitamin deficiencies, liver or kidney dysfunction, other metabolic disorders, and signs of abnormal immune system activity. An examination of cerebrospinal fluid that surrounds the brain and spinal cord can reveal abnormal antibodies associated with some immune-mediated neuropathies.

 

Based on the results of the neurological exam, physical exam, patient history, and any previous screening or testing, the following additional tests may be ordered to help determine the nature and extent of the neuropathy:

• Nerve conduction velocity (NCV) tests can measure the degree of damage in large nerve fibres
• Electromyography (EMG) involves inserting a fine needle into a muscle to record electrical activity when muscles are at rest and when they contract.
• Magnetic resonance imaging (MRI) can show muscle quality and size, detect fatty replacement of muscle tissue, and can help rule out tumours, herniated discs, or other abnormalities that may be causing the neuropathy.
• Nerve biopsy involves removing and examining a sample of nerve tissue, most often from the lower leg. Although this test can provide valuable information about the degree of nerve damage, it is an invasive procedure that is difficult to perform and may itself cause neuropathic side effects.
• Skin biopsy is a test in which doctors remove a thin skin sample and examine nerve fibre endings.

 

Treatment

  • Address underlying conditions
  • Symptom management – medication oral and topical
  • Some evidence in use of TENS
  • Acupuncture