The peripheral nerves are the nerves located outside of the brain and spinal cord. This huge communication network transmits signals between the central nervous system (the brain and spinal cord) and all other parts of the body.
There are three types of peripheral nerves:
- Sensory nerves that receive sensation from the skin, such as temperature, pain, vibration or touch.
- Motor nerves that control muscle movement.
- Autonomic nerves that control organs which automatically regulate body functions such as blood pressure, perspiration, heart rate, digestion and bladder function.
What is peripheral neuropathy?
Peripheral neuropathy (PN) is an umbrella term for many conditions that damage the peripheral nerves and disrupt nerve signaling through:
- Loss of signals normally sent (like a broken wire).
- iInappropriate signaling when there shouldn’t be any (like static on a telephone line).
- Errors that distort the messages being sent (like a wavy television picture).
Peripheral neuropathy that only damages one nerve is called mononeuropathy. When two or more nerves are affected in different areas, it is called multiple mononeuropathy or mononeuropathy multiplex. In most cases, many or most of the nerves are affected. This is called polyneuropathy.
Common autoimmune diseases that manifest with peripheral neuropathy include Sjogren’s syndrome, systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA).
What are the symptoms?
Symptoms can range from mild to disabling and vary depending on the type of nerve fibers affected and the type and severity of damage. They may develop over days, weeks, or years. Symptoms may even improve on their own and not require advanced care. This is because peripheral nerve cells continue to grow throughout life, unlike those in the central nervous system (CNS).
- Motor nerve damage - most commonly associated with muscle weakness, painful cramps, fasciculations (uncontrolled muscle twitching visible under the skin) and muscle shrinking.
- Sensory nerve damage - causes various symptoms because sensory nerves have a broad range of functions. Damage to large sensory fibers harms the ability to feel vibrations and touch, especially in the hands and feet.
- The “small fibers” without myelin sheaths (protective coating, like insulation that normally surrounds a wire) include fiber extensions called axons that transmit pain and temperature sensations.
- Small-fiber polyneuropathy can interfere with the ability to feel pain or changes in temperature.
- Autonomic nerve damage affects the axons in small-fiber neuropathies, which can cause excess sweating, heat intolerance, inability to expand and contract the small blood vessels that regulate blood pressure, and gastrointestinal symptoms.
What causes peripheral neuropathy?
Peripheral neuropathy is common. It affects more than 20 million people in the US. Most forms are either genetic (something you're born with) or acquired (arises later in life) and are caused by many different things, with diabetes being the most common cause. Sometimes, the cause cannot be determined. This is called idiopathic peripheral neuropathy.
Causes of symptomatic acquired peripheral neuropathy include:
- Physical traumatic injury is the most common cause of acquired mononeuropathy, which can be caused by automobile accidents, falls, sports, or medical procedures. Less severe trauma like a cast exerting prolonged pressure on a nerve or or repetitive, forceful activities that can cause ligaments or tendons to swell, which narrows slender nerve pathways, can also cause peripheral neuropathy.
- Diabetes is the leading cause of polyneuropathy in the United States. About 60 to 70 percent of people with diabetes have mild to severe forms of damage to sensory, motor, and autonomic nerves.
- Vascular and blood problems that decrease oxygen supply to the peripheral nerves can lead to nerve damage.
- Systemic (body-wide) autoimmune diseases, in which the immune system mistakenly attacks various parts of the body, can directly target nerves or surrounding tissue that can trap and compress nerves.
- Autoimmune diseases that attack nerves only are often triggered by recent infections that can develop quickly or slowly, or become chronic and fluctuate in severity.
- Hormonal imbalances that can disturb normal metabolic processes and cause tissues to swell and comppress or pinch peripheral nerves.
- Kidney and liver disorders can lead to abnormally high amounts of toxic substances in the blood that can damage nerves.
- Nutritional or vitamin imbalances, alcoholism, and exposure to toxins - vitamin B12 deficiency and excess vitamin B6 are the best known vitamin-related causes.
- Certain cancers and benign tumors - for example, a tumor can compress a nerve and cause peripheral neuropathy.
- Certain chemotherapy drugs - can cause peripheral neuropathy, which may continue long after stopping chemotherapy. Radiation therapy also can cause nerve damage that sometimes starts months or years later.
- Infections can attack nerve tissues and cause neuropathy.
- Viruses such as varicella-zoster virus (which causes chicken pox and shingles), West Nile virus, cytomegalovirus, and herpes simplex target sensory fibers, causing attacks of sharp, lightning-like pain. Lyme disease, carried by tick bites, can cause a range of neuropathic symptoms, often within a few weeks of being infected. The human immunodeficiency virus (HIV), which causes AIDS, can extensively damage the central and peripheral nervous systems.
Resource
National Institute of Health (NIH) Peripheral Neuropathy Fact Sheet.
Physical Therapy for Peripheral Neuropathy
Physical therapy can help you maintain strength, mobility and function regardless of the underlying cause of your peripheral neuropathy. Diabetics must also closely monitor and control their blood glucose levels.
To help get you on the road to recovery, your physical therapist may do manual therapy to help relieve pain and stiffness while increasing your flexibility. You may then start doing gentle stretches and flexibility exercises at home such as yoga or Pilates to help keep your joints flexible and reduce your chances of injury during other activities.
Your physical therapist may include a strength-building plan that increases your heart and breathing rates as well as strengthening your muscles, which may include exercises similar to these:
- Brisk walking (outside or inside on a treadmill)
- Swimming or aquatic exercises
- Stationary bicycle
Your physical therapist may also develop a balance and coordination program to help decrease your risk of falling and help prevent injuries. Another effective treatment for peripheral neuropathy is Nerve Gliding, a therapy technique involving specific movements that move and "glide" your nerves. This helps promote nerve healing and return to function, while also decreasing peripheral neuropathy pain.
Please contact us for more information on how we can relieve your peripheral neuropathy pain and help promote nerve healing and optimal nerve function.
