Peripheral Neuropathy

Peripheral neuropathy affects millions of people worldwide, causing damage to nerves outside the brain and spinal cord. This condition often leads to pain, numbness, and weakness, particularly in the hands and feet, significantly impacting daily life and quality of activities.

Table of contents

• What is peripheral neuropathy?
• How common is the condition?
• Symptoms
• Types of nerve fibers affected
• Causes and risk factors
• Diagnosis
• Treatment options
• Living with peripheral neuropathy

What is peripheral neuropathy?

Peripheral neuropathy happens when the nerves that are located outside of the brain and spinal cord are damaged^[1]. Your nervous system has two parts: the central nervous system (which includes your brain and spinal cord) and the peripheral nervous system (which consists of all the other nerves in your body)^[2]. The peripheral nervous system sends information from the brain and spinal cord to the rest of the body through motor nerves, and also sends sensory information back to the central nervous system through sensory nerves^[1].

When peripheral nerves cannot send and receive signals like they should, it can have serious consequences for the body^[3]. This condition often causes weakness, numbness and pain, usually in the hands and feet, but it can also affect other areas and body functions including digestion and urination^[1].

The term “peripheral” comes from the Greek word meaning “around,” indicating that these nerves are outside of or away from the central nervous system. The term neuropathy combines two Greek words: “neuron” meaning “nerve” and “pathos” meaning “affliction” or “condition”^[2].

How common is the condition?

Peripheral neuropathy is common. The prevalence in the general population ranges from 1% to 7%, with higher rates among those older than 50 years^[5]. Globally, about 2.4% of people have a form of peripheral neuropathy. Among people 45 and older, that percentage rises to between 5% and 7%^[2]. In the United Kingdom, it’s estimated that almost 1 in 10 people aged 55 or over are affected by peripheral neuropathy^[4].

Peripheral neuropathy can affect anyone, regardless of age, sex, race or ethnicity, personal circumstances, or medical history. However, the risk of developing peripheral neuropathy increases as you get older, particularly because it is very common with some age-related diseases^[2].

Symptoms

People with peripheral neuropathy usually describe the pain as stabbing, burning or tingling^[1]. Early peripheral neuropathy may present as sensory changes that are often progressive, including sensory loss, numbness, pain, or burning sensations in a “stocking and glove” distribution of the extremities^[5]. This means symptoms typically begin in the feet and, over time, gradually start to affect shorter nerves, so it feels as if it’s spreading upward, and later affects the hands^[4].

The main symptoms of peripheral neuropathy can include^[4]:

• Gradual onset of numbness, prickling, or tingling in your feet or hands, which can spread upward into your legs and arms^[1]
• Sharp, jabbing, throbbing or burning pain
• Extreme sensitivity to touch
• Loss of balance and coordination
• Muscle weakness, especially in the feet
• Pain during activities

These symptoms are usually constant, but may come and go^[4]. Later stages may involve proximal numbness, distal weakness, or atrophy^[5]. Sometimes the painful symptoms are worse at night^[1].

It’s important to see a doctor if you experience the early symptoms of peripheral neuropathy, including pain, tingling or loss of sensation in the feet, loss of balance or weakness, or a cut or ulcer on your foot that’s not getting better^[4].

Types of nerve fibers affected

Every nerve in the peripheral system has a specific job. Symptoms depend on the type of nerves affected^[1]. Nerves are divided into three main types:

Sensory nerves receive sensation, such as temperature, pain, vibration or touch, from the skin. When these nerves are damaged, you might experience numbness, tingling, or increased sensitivity^[1].

Motor nerves control muscle movement. Damage to motor nerves can lead to muscle weakness, loss of reflexes, muscle wasting in the hands and feet, and loss of balance^[1].

Autonomic nerves control functions such as blood pressure, sweating, heart rate, digestion and bladder function^[1]. Problems with these nerves can cause dizziness when getting up from a bed or chair, and sexual dysfunction^[4].

Most neuropathies affect all three types of nerve fibers to varying degrees, while others mostly affect one or two types. Doctors use terms such as predominantly motor neuropathy, predominantly sensory neuropathy, sensory-motor neuropathy, or autonomic neuropathy to describe different conditions^[3].

Causes and risk factors

Peripheral neuropathy can result from traumatic injuries, infections, metabolic problems, inherited causes and exposure to toxins^[1]. More than 100 types of peripheral neuropathy have been identified, each with its own causes, symptoms, and treatment options^[3]. Common identifiable causes include diabetes mellitus, nerve compression or injury, alcohol use, toxin exposure, hereditary diseases, and nutritional deficiencies^[5].

In the United States and the United Kingdom, diabetes (both type 1 and type 2) is the most common cause of peripheral neuropathy^[4]. Over time, the high blood sugar levels associated with diabetes can damage the nerves and the small blood vessels that nourish them^[1]. Peripheral neuropathy affects 25% to 50% of patients with diabetes, depending on factors such as the patient’s age, number of years with diabetes, and level of diabetes control^[5].

Physical injury to the nerves can also cause neuropathy. This includes nerve compression or pressure on a nerve, as with carpal tunnel syndrome, or injuries from accidents, casts, braces, or crutches^[12].

Other causes include viral infections such as shingles, certain medications (some antibiotics, heart medications, and blood pressure medicines), heavy alcohol use, exposure to toxic chemicals, and having certain medical conditions like rheumatoid arthritis, lupus, kidney disease, Lyme disease, or thyroid problems^[12].

Some medications, particularly certain chemotherapy drugs, can cause peripheral neuropathy. Medications that may increase the risk include platinum compounds, taxanes, vinca alkaloids, thalidomide, and several others^[11].

Peripheral neuropathy is idiopathic (meaning the cause cannot be identified) in 25% to 46% of cases, and this is more common with increasing patient age^[5].

Diagnosis

Diagnosis requires a comprehensive history, physical examination, and judicious laboratory testing^[5]. Besides a physical exam, which may include blood tests, diagnosis usually requires a full medical history and a neurological exam^[8].

Your healthcare professional will look at your medical history, including your symptoms, lifestyle, exposure to toxins, drinking habits and a family history of nervous system diseases. During the neurological exam, they might check your tendon reflexes, muscle strength and tone, ability to feel certain sensations, and balance and coordination^[8].

Initial laboratory evaluation includes a complete blood count; a comprehensive metabolic profile; fasting blood glucose, vitamin B12, and thyroid-stimulating hormone levels; and serum protein electrophoresis with immunofixation^[5].

Your healthcare professional may order additional tests, including^[8]:

• Blood tests to detect low levels of vitamins, diabetes, signs of inflammation or metabolic issues that can cause peripheral neuropathy
• Imaging tests such as CT or MRI scans to look for herniated disks, pinched nerves, growths or other problems affecting the blood vessels and bones
• Nerve function tests such as electromyography (EMG) and nerve conduction studies to measure electrical activity in your muscles and how nerves respond to electrical current
• Nerve biopsy to remove a small portion of nerve tissue for examination

Patients with peripheral neuropathy should be referred for electrodiagnostic studies if symptoms are worrisome (such as acute onset, asymmetrical symptoms, predominant motor or autonomic symptoms, or rapidly progressive clinical course) or if initial workup is normal and symptoms persist^[5].

Treatment options

Treatment for peripheral neuropathy depends on the symptoms and underlying cause^[4]. Not all of the underlying causes of neuropathy can be treated, but treatment of peripheral neuropathy focuses on managing the underlying cause when possible^[3].

If you have diabetes, ensuring it is well controlled may help improve neuropathy, or at least stop it getting worse. This may involve lifestyle changes, such as stopping smoking, cutting down on alcohol, maintaining a healthy weight and exercising regularly^[4]. If the neuropathy is caused by vitamin B12 deficiency, it can be treated with B12 injections or tablets^[10].

For pain management, nerve pain may be treated with prescribed medicines called neuropathic pain agents, as standard painkillers often do not work^[4]. Several classes of medications can help alleviate neuropathic pain^[1]. The main medicines recommended for neuropathic pain include^[10]:

• Amitriptyline – also used for treatment of headaches and depression
• Duloxetine – also used for treatment of bladder problems and depression
• Pregabalin and gabapentin – also used to treat epilepsy, headaches or anxiety

These medicines should usually be started at the minimum dose, with the dose gradually increased until you notice an effect. Common side effects are tiredness, dizziness or feeling “drunk”^[10].

Other treatment options include physical therapy to increase muscle strength and help build muscle control^[8]. Some people find that physical therapy, acupuncture, or transcutaneous electrical nerve stimulation (TENS) helps relieve pain^[8]. TENS is a method of therapy that works by inhibiting pain signals from reaching the brain through placing very small electrical impulses on specific nerve paths^[11].

For more severe cases, spinal cord stimulation is a state-of-the-art treatment that uses a tiny, implantable device to disrupt nerve signals responsible for pain^[18].

Living with peripheral neuropathy

Living with chronic pain or disability presents daily challenges. The peripheral nerves have a great ability to heal, and even though it may take months, recovery can occur^[11]. However, in some situations, symptoms of neuropathy may lessen but not completely go away. For example, nerve injury caused by radiation often does not recover well. Neuropathy caused by chemotherapy is also difficult to cure, and recovery may take 18 months to five years or longer^[11].

Several lifestyle changes and coping strategies can help you manage the condition^[20]:

Exercise regularly. Exercise offers plenty of benefits for people with neuropathy. Not only can it help you shed excess pounds that could be pressing on nerves, but it can elevate your mood and improve your circulation. Some exercises can also improve your balance, which is often impaired in people with neuropathy in their feet^[18].

Quit smoking. Smoking interferes with circulation, increasing your risk of developing neuropathy while also making your symptoms worse. Quitting smoking improves circulation for better nerve health^[18].

Stay involved. One of the best ways to combat anxiety and depression is to get out of your house and take part in activities you enjoy. Consider reaching out to a support group. The Foundation for Peripheral Neuropathy maintains a list of support groups, including online groups^[18].

Set priorities. Decide which tasks you need to do on a given day and which can wait until another time. Stay active, but don’t overdo it^[20].

Acceptance and acknowledgement. Accept and acknowledge the negative aspects of the illness, but then move forward to become more positive to find what works best for you^[20].

If you have neuropathy in your feet, it’s important to have them checked during each office visit to help prevent problems^[8]. People with diabetes need to be especially careful about managing their blood sugar, blood pressure, and cholesterol. Good management can help prevent or slow the progression of peripheral neuropathy^[1].

If you experience symptoms of peripheral neuropathy, don’t put off getting help. The sooner peripheral neuropathy is diagnosed, the better the chance of limiting the damage and preventing further complications^[4].