Peripheral neuropathy

Have you ever felt like your hands and feet are asleep, even when you're wide awake and up and moving? Or have you've experienced tingling, burning or weird zaps in your fingers or toes? If so, those could be signs of peripheral neuropathy.

Peripheral neuropathy is an umbrella term for more than 100 types of neuropathies, with each affecting various parts of the peripheral nervous system, the sensory communication pathway from your brain to your muscles.

Think of peripheral neuropathy as a faulty phone line. The message (touch, pain, temperature) isn't getting through clearly or maybe not at all. This can lead to all sorts of symptoms from numbness and weakness to balance problems.

How the peripheral nervous system works

The peripheral nervous system is like the chatty network connecting your brain and spinal cord (the central nervous system) to the rest of your body. It's constantly sending messages back and forth, keeping you informed and in action. This communication pathway has two lines:

• Sensory (afferent): This line carries information to the brain and spinal cord. The sensory receptors pick up information about the world around you (like feeling the warmth of the sun) and send it as electrical signals through sensory nerves to the brain.
• Motor (efferent): This line carries information from the brain and spinal cord out to your muscles and organs. It's like the brain sending instructions through motor nerves, telling your muscles to move (like raising your hand to wave) or your heart to beat faster.

However, peripheral nervous system communication pathway isn't just a simple back-and-forth. It has two major divisions:

• Somatic nervous system: This controls your voluntary actions, like walking, talking or playing a video game.
• Autonomic nervous system: This handles your involuntary functions, like digestion, breathing and your heart rate. It's like the autopilot system, keeping things running smoothly even when you're not thinking about them.

The autonomic nervous system itself has two branches:

• Sympathetic nervous system: This kicks in during fight-or-flight situations, getting your body ready for action by increasing heart rate, breathing and sweating.
• Parasympathetic nervous system: This calms things down after the action is over, slowing down your heart rate, breathing and digestion.

However, factors such as infections, injuries, elevated blood sugar levels and genetics can lead to nerve damage, causing one of the types of peripheral neuropathy.

Types of peripheral neuropathy

Neuropathy refers to a condition involving damage or dysfunction of nerves, often resulting in symptoms such as numbness, tingling, weakness or pain. Peripherial neuropathy is the umbrella for several types of neuropathies. The most common types include:

• Diabetic neuropathy: This type of neuropathy is specifically associated with diabetes and is one of the most prevalent complications of the condition. It can affect nerves throughout the body but often impacts the feet and legs first.
• Autonomic neuropathy: Autonomic neuropathy affects the nerves that control involuntary bodily functions such as heart rate, blood pressure, digestion and bladder function. It can result in symptoms such as dizziness, fainting, gastrointestinal issues, sexual dysfunction and problems with sweating.
• Hereditary sensory motor neuropathy: Also called inherited neuropathy or familial neuropathy, this type is caused by genetic mutations passed down through families. Examples include Charcot-Marie-Tooth disease and personal muscular neuropathies.
• Toxic neuropathy: Toxic neuropathy occurs due to exposure to certain substances, such as heavy metals (e.g., lead, mercury), medications (e.g., chemotherapy drugs, certain antibiotics), industrial chemicals or alcohol.
• Idiopathic neuropathy: In some cases, the cause of neuropathy remains unknown, and it is termed idiopathic neuropathy. Despite extensive evaluation, no underlying cause can be identified.
• Neuralgic amyotrophy (NA): Also known as Parsonage-Turner syndrome (PTS), this condition is thought to be caused by abnormal autoimmune reactions that damage peripheral nerves. Leads to extreme pain and muscle weakness in the shoulder.

These are some of the primary types of peripheral neuropathy, each with its own set of causes, symptoms and treatments.

What causes peripheral neuropathy?

Peripheral neuropathy occurs when nerves are damaged or destroyed and can no longer send messages from the brain and spinal cord to the muscles or organs in the body.

Diabetes is the most common cause of peripheral neuropathy, and it’s sometimes called diabetic neuropathy. One-third to one-half of people with diabetes have peripheral neuropathy.

Over time high blood sugar can cause nerve damage, interfering with the ability to send signals to the brain and spinal cord. High blood sugar also can weaken small blood vessels that supply the nervous system with oxygen and nutrients.

Other causes of peripheral neuropathy include:

• Alcoholism
• Autoimmune diseases
• Certain kinds of cancer and chemotherapy used to treat them
• Certain medications
• Exposure to toxins
• Hereditary neuropathy such as Charcot-Marie-Tooth disease
• Infections such as Lyme disease, shingles and AIDS
• Kidney, liver or thyroid disease
• Physical injury or trauma from a fall or other accident
• Pinched nerves
• Poor nutrition or vitamin deficiency
• Repetitive motion affecting a single nerve group
• Smoking

What are the four stages of peripheral neuropathy?

Peripheral neuropathy progresses through different stages. It is important to understand what stage your neuropathy is in so your doctor can provide the appropriate treatment options.

Each stage is based on the severity and progression of symptoms.

• Stage 1: In the early stage, you may notice mild numbness and pain in your hands and feet. Something will feel “off.” During this stage, symptoms may be so mild you ignore them.
• Stage 2: In this stage your pain will become more noticeable and consistent that you can’t ignore it.
• Stage 3: Your pain becomes much more intense in this stage. The pain can feel so intense that you will have difficulty doing daily tasks.
• Stage 4: When peripheral neuropathy reaches this stage, you will feel complete numbness and loss of sensation in your hands and feet. The risk of amputation increases in this stage.

While there is no cure for peripheral neuropathy, you can slow its progression by seeing your provider when you first notice possible peripheral neuropathy symptoms.

Peripheral neuropathy symptoms

Symptoms of peripheral neuropathy may vary depending on which nerves are damaged.

Sensory or motor nerve damage can cause symptoms such as:

• Extreme sensitivity to touch
• Feeling like you’re wearing socks or gloves when you’re not
• Muscle weakness
• Numbness and tingling in the hands or feet
• Sharp or jabbing neuropathic pain
• Throbbing or burning neuropathic pain

Symptoms of autonomic nerve damage, include:

• Bowel, bladder or digestive issues
• Excessive sweating or being unable to sweat
• Intolerance to heat
• Low blood pressure that leads to lightheadedness or dizziness

If you are experiencing any of the above symptoms it is important to see your doctor as soon as possible to discuss proper treatment options.

Peripheral neuropathy diagnosis

Your doctor will ask about your symptoms and anything that triggers or relieves them. They may also ask you about any exposure to toxins, alcohol or tobacco use, history of infections or diabetes and family history of neurological diseases.

Various blood tests may be ordered to detect diabetes, vitamin deficiencies, liver, thyroid or kidney dysfunction, infections or signs of abnormal immune system activity.

Your provider may also recommend nerve function and imaging tests to identify any nerve damage. Imaging tests include:

• CT scan: CT scans of the spine can show herniated discs, spinal stenosis (narrowing of the spinal canal), tumors and bone irregularities that may affect nerves.
• MRI: An MRI of the spine can reveal tumors or nerve root compression, also known as a pinched nerve, that could be causing your peripheral neuropathy.

Nerve function tests are a valuable tool in diagnosing peripheral neuropathy. These tests include:

• Nerve conduction velocity (NCV) test: This test measures signal strength and speed along specific large motor and sensory nerves and reveals the location of nerve damage.
• Electromyography (EMG) test: For this test, tiny needles connected to electrodes are inserted into specific muscles to record their electrical activity at rest and during contraction. Test results show any abnormal muscular electrical and can help differentiate between muscle and nerve disorders.

Peripheral neuropathy treatment

Although there is no way to repair the nerves through treatment of neuropathy, you can stop further nerve damage and relieve neuropathy pain. The goal of treatment is to manage what’s causing your neuropathy and improve symptoms.

Your doctor may use a combination of medications, therapy or surgery to treat peripheral neuropathy.

Peripheral neuropathy medication options

Medications can be used to improve symptoms and relieve pain, including:

• Antidepressants
• Pain medications, such as ibuprofen or naproxen
• Anti-seizure medications, such as gabapentin and pregabalin
• Topical creams or skin patches for neuropathic pain

Therapy options

Therapy options are often used to improve motor skills, strengthen muscles or reduce pressure on the nerves. Therapies used may include:

• Acupuncture, massage and cognitive behavioral therapy to help with neuropathic pain management
• Hand or foot braces to stabilize the muscles and nerves
• Orthopedic shoes to improve walking difficulties and help prevent foot injuries
• Physical therapy to learn muscle stretching and strengthening techniques that can help with pain relief
• Regular exercise to deliver more blood, oxygen and nutrients to nerve endings, improve muscle strength and limit muscle atrophy
• Splints for carpal tunnel problems to reduce pressure on the compressed nerve and allow it to heal
• Surgery for pinched nerves or carpal tunnel syndrome

Managing peripheral neuropathy

If you have peripheral neuropathy, you should wear properly fitted shoes and avoid walking barefoot to prevent injury.

If you have diabetes, it's important to control your blood sugar to prevent further nerve damage. Take your insulin or medication as prescribed and follow a diet recommended by your doctor or dietitian.

It's also important to inspect your feet regularly to check for injuries or infection. Because decreased sensation may develop eventually, you might not notice an injury or infection. For example, someone who has peripheral neuropathy could step on a tack without noticing it.

If the wound goes unnoticed, it can become infected and lead to possible amputation. If you can’t inspect your own feet, ask a family member or friend to look at your feet. Another option is to use a mirror.