The peripheral nervous system (PNS) contains the body’s nerves not included in the central nervous system (CNS). The CNS consists of the brain and spinal cord, while the PNS includes all the cranial and spinal nerves and their roots, branches, peripheral nerves, and neuromuscular junctions. The PNS allows the CNS to communicate with the body’s limbs, organs, and skin. Peripheral nerves send sensory information to the CNS and transport the CNS’s instructions on reacting to stimuli to the rest of the body. Sometimes, the peripheral nerves can become damaged, which leads to peripheral neuropathy.
Peripheral neuropathy occurs when peripheral nerves become damaged and can no longer effectively connect the CNS to the rest of the body. This loss of connection results in weakness, numbness, and pain in the affected limbs. Most living with peripheral neuropathy typically experience symptoms in their hands or feet, but this condition can affect any part of the body. Diabetes is the leading cause of peripheral neuropathy, but trauma to the nerves, infections, exposure to toxins, metabolic problems, and genetic disorders can also cause it.
Peripheral neuropathy can disrupt nerve signaling and communication in several different ways. The first disruption occurs when the PNS loses sensory signals that should reach the CNS. The second disruption occurs when the peripheral nerves react when they should not be. The third disruption to nerve signaling is when peripheral nerves do not respond when they should, or they distort the message from the body or CNS. These distortions result in patients being unable to feel pain and being unable to control their reflexes.
Symptoms of peripheral neuropathy can range from mild to severe, but this condition rarely presents life-threatening symptoms. The symptoms patients experience significantly depend on the type of peripheral nerve fibers affected and the type and severity of damage to them. Patients may only experience one kind of nerve damage, while others will experience symptoms because more than one type of peripheral nerve sustained damage.
Researchers continue to study all forms of neuropathy to learn more about the genetic component of this condition and discover more effective treatment options.
Preventing the development of peripheral neuropathy is possible for some by
Managing medical conditions that increase the risk of developing this condition
Eating a well-balanced diet
Exercising regularly under your physician’s direction
Avoiding factors contributing to nerve damage if possible: repetitive motions, cramped positions that place pressure on nerves, exposure to toxic chemicals, smoking, excessively consuming alcohol
Your treatment depends on the type and location of your nerve damage and your symptoms. Your physician will treat the underlying causes of your neuropathy in addition to treating the symptoms. Treatment options include:
Immunosuppressive medicine to reduce inflammation
Pain medication: over-the-counter pain relievers and topical creams, prescription pain relievers, antidepressants, and anti-seizure medication
Braces or other mobility devices, such as canes, wheelchairs, and crutches
Your symptoms greatly depend on which nerves are damaged.
Common symptoms associated with all types of peripheral neuropathy include:
Sharp, jabbing, throbbing, or burning pain
Feeling a buzzing or shocking sensation in your body
Extreme sensitivity to touch
Pain during activities that should not be painful, such as placing a blanket over your feet
Gradual onset of numbness in your limbs
Feeling like you are wearing a tight glove or sock when you are not
Increased pain at night
Common symptoms associated with motor nerve damage:
Decreased balance and mobility
Common symptoms associated with sensory nerve damage:
Inability to feel vibrations or touch
Loss of reflexes
Inability to feel pain or temperature sensations
Common symptoms associated with autonomic nerve damage:
Difficulty eating or swallowing
Inability to regulate blood pressure
These symptoms may lead to complications, such as
Burns and skin trauma because of your inability to feel temperature changes or pain in numb body parts
Worsening infections or other injuries due to your inability to feel pain
Falls due to weakness and loss of sensation in lower extremities
Early diagnosis is critical to control your symptoms and prevent further damage to your peripheral nerves.
Your healthcare provider will ask about the following information:
The frequency, duration, and severity of your symptoms
Your lifestyle habits and exercise regimen
All medications you take, including over-the-counter medicine, supplements, vitamins, illicit drugs, or prescription medication
Your medical history, including other medical conditions
Any recent or past trauma to the nerves
Familial history of similar symptoms
Your physician will conduct a physical and neurological exam to identify the cause and severity of nerve damage. They will check your tendon reflexes, muscle strength, muscle tone, and sensation ability. Depending on the severity of your peripheral neuropathy, they may observe your walking gait and check your posture, coordination, and balance abilities.
Your physician will order diagnostic tests, such as:
Blood and urine tests
Nerve conduction velocity (NCV) to determine what nerves and nerve types are affected and their cause
Neurodiagnostic skin biopsy
Muscle and nerve ultrasound
There are more than one hundred different types of peripheral neuropathy with their own unique symptoms and treatment options.
Peripheral neuropathy can be:
Mononeuropathy: affects only one nerve
Multiple mononeuropathies or mononeuropathy multiplex: affecting two or more nerves in different areas
Polyneuropathy: affects many or most nerves
Peripheral neuropathy can affect your
Motor nerves, which consciously control all your muscles
Sensory nerves, which transmit sensory information
Autonomic nerves, which control the organs that unconsciously regulate functions such as breathing or digesting food
Autoimmune disorders: These may be body-wide, meaning they mistakenly attack the body’s own tissues, which can cause nerve problems. Some autoimmune diseases directly attack nerves, such as Guillain-Barre syndrome
Bone marrow disorders
Diseases affecting the kidneys, liver, connective tissue, and thyroid
Exposure to poisons
Infections, such as Lyme disease, shingles, HIV, hepatitis B and C
Medications, especially those used to treat cancer
Trauma or pressure on nerves
Vascular and blood problems that decrease oxygen supply to peripheral nerves
Other risk factors include:
Poorly controlled diabetes
Family history of neuropathy
Most neuropathies affect all types of nerves to some degree.
About 60-70% of people living with diabetes in the United States live with polyneuropathy.
Sexual dysfunction caused by peripheral neuropathy affects men more than women.