What is Peripheral Neuropathy?
The peripheral nerves are those outside the spinal cord and brain, and they are responsible for sending sensory information to and from the central nervous system. Damage to these nerves is called peripheral neuropathy.
This condition often causes weakness, numbness and pain, usually in the hands and feet. It also can affect other areas and body functions including digestion and urination.
What are the symptoms of Peripheral Neuropathy?
Symptoms depend on the type of nerves affected. Nerves are divided into:
- Sensory nerves that receive sensation, such as temperature, pain, vibration or touch, from the skin.
- Motor nerves that control muscle movement.
- Autonomic nerves that control functions such as blood pressure, sweating, heart rate, digestion and bladder function.
Symptoms of peripheral neuropathy might include:
- Gradual onset of numbness, prickling, or tingling in your feet or hands. These sensations can spread upward into your legs and arms.
- Sharp, jabbing, throbbing or burning pain.
- Extreme sensitivity to touch.
- Pain during activities that shouldn’t cause pain, such as pain in your feet when putting weight on them or when they’re under a blanket.
- Lack of coordination and falling.
- Muscle weakness.
- Feeling as if you’re wearing gloves or socks when you’re not.
- Inability to move if motor nerves are affected.
If autonomic nerves are affected, symptoms might include:
- Heat intolerance.
- Excessive sweating or not being able to sweat.
- Bowel, bladder or digestive problems.
- Drops in blood pressure, causing dizziness or light-headedness.
What are the causes of Peripheral Neuropathy?
Causes
Peripheral neuropathy is nerve damage caused by several different conditions. Health conditions that can cause peripheral neuropathy include:
- Diabetes and metabolic syndrome. This is the most common cause. Among people with diabetes, more than half will develop some type of neuropathy.
- Autoimmune diseases. These include Sjogren’s syndrome, lupus, rheumatoid arthritis, Guillain-Barre syndrome, chronic inflammatory demyelinating polyneuropathy and vasculitis. Also, some cancers related to the body’s immune system can cause polyneuropathy. These are a form of autoimmune disorder called paraneoplastic syndrome.
- Alcohol use disorder. Unhealthy dietary choices made by people with alcohol use disorder, also known as alcoholism, and poor absorption of vitamins can lead to low amounts of essential vitamins in the body.
- Injury or pressure on the nerve. Injuries, 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.
- Low vitamin levels. B vitamins, including B-1, B-6 and B-12, as well as copper and vitamin E are crucial to nerve health.
- Infections. These include certain viral or bacterial infections, including Lyme disease, shingles, hepatitis B and C, leprosy, diphtheria, and HIV.
- Inherited disorders. Disorders such as Charcot-Marie-Tooth disease are hereditary types of neuropathies that run-in families.
- Tumors. Cancerous growths, also called malignant, and noncancerous growths, also called benign, can grow on or press on nerves.
- Bone marrow disorders. These include a protein in the blood that isn’t usually there, called monoclonal gammopathies, a rare form of myeloma that affects the bones, lymphoma and the rare disease amyloidosis.
- Other diseases. These include metabolic conditions such as kidney disease or liver disease, and an underactive thyroid, also known as hypothyroidism.
- Exposure to poisons. Toxic substances include industrial chemicals and heavy metals such as lead and mercury.
- Medicines. Certain medicines, especially chemotherapy used to treat cancer, can cause peripheral neuropathy.
In some cases, no cause can be identified. This is called idiopathic peripheral neuropathy.
Complications of Peripheral Neuropathy:
- Burns, skin injuries and wounds on the feet. You might not feel temperature changes or pain on parts of your body that are numb.
- Infection. Your feet and other areas that lack sensation can become injured without your knowing. Check these areas regularly, wear close-toed, well-fitting shoes and treat minor injuries before they become infected, especially if you have diabetes.
- Falls. Weakness and loss of sensation may be associated with lack of balance and falling. Installing handrails in the bathroom, using canes or walkers when needed, and ensuring that you are walking only in well-lit rooms can decrease fall risk.
Tests that can help in diagnosing Peripheral Neuropathy?
- Blood tests (these can detect many problems, ranging from immune system problems to toxins and poisons, especially metals like mercury or lead).
- NCS (Nerve Conduction Study)
- EMG (Electromyogram).
- Nerve ultrasound.
- Nerve biopsy.
- Genetic testing.
- Magnetic resonance imaging (MRI).
Management of Peripheral Neuropathy?
Treatment either targets the underlying cause, or it aims to provide symptomatic pain relief and prevent further damage. Treatments may include:
- Maintaining nerve health by keeping a healthy lifestyle. This can include exercising, eating healthy, keeping a healthy weight, correcting any vitamin deficiencies, and not drinking alcohol or smoking.
- Managing blood sugar in cases of diabetic neuropathy, to prevent further nerve damage.
- Taking immunosuppressive drugs when the cause is an autoimmune disorder, or using plasmapheresis, a procedure that cleans the blood to reduce inflammation.
- Removing the exposure to a suspected toxin, or stopping a problematic drug, to halt further nerve damage.
- Using hand and foot braces or orthopaedic shoes to help cope with physical disability from motor symptoms.
Medications for neuropathic pain
Medications that may help relieve symptoms, but do not cure the problem, include:
- GABAergic medications like Gabapentin, Pregabalin
- antidepressants, such as Venlafaxine
- Duloxetine, which may help people with chemotherapy-induced neuropathy.
- prescription skin patches, such as Lidoderm, for temporary, localized pain relief. This contains the local anesthetic lidocaine. The patches are like bandages, and a person can cut them to size.
- non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, which may help control milder pain. These are available over the counter.
- Topical ointments and creams, such hot pepper-containing capsaicin, which may also ease pain. A person can also get patches.
- drugs normally used for epilepsy, such as carbamazepine