Peripheral Neuropathy

Peripheral neuropathy can affect one nerve (mononeuropathy), two or more nerves in different areas (multiple mononeuropathy or mononeuropathy multiplex), or many nerves (polyneuropathy).

Most cases of peripheral neuropathy are polyneuropathy. About 75 percent of polyneuropathies are length-dependent, which means symptoms begin or are most severe in the nerve endings found the farthest from the central nervous system, like those in the feet.

Peripheral neuropathy symptoms will depend on the type of nerves that are affected: motor, sensory, or autonomic nerves.

• Motor nerves control muscle movements, like those used for walking and talking. When these nerves are damaged, the most common symptom is muscle weakness. Other symptoms include painful cramps, uncontrollable muscle twitching, and muscle shrinking
• Sensory nerves transmit sensations of touch, pain, vibration, and temperature. When these nerves are damaged, it affects a person’s ability to feel or notice sensory changes. Symptoms can include numbness or tingling that begins in the feet or hands, or sharp, throbbing, or burning pain. Some people may experience severe pain from light touch or feel like they’re wearing gloves or socks when they’re not.
• Autonomic nerves control unconscious body functions like blood pressure, sweating, breathing, and digestion. When these nerves are damaged, it can cause heat intolerance, excessive sweating, trouble regulating blood pressure, gastrointestinal problems, or, in rare cases, difficulty eating and swallowing.

Because symptoms are so varied, it can be difficult to diagnose peripheral neuropathy. In addition to physical and neurological exams, a doctor will review a person’s medical and family history and take note of any diseases or conditions that may cause nerve damage. 

A blood test can indicate some causes of acquired neuropathies, including diabetes, vitamin deficiencies, liver or kidney disorders, infections, or abnormal immune system activity. Genetic tests may be used to diagnose certain genetic forms of neuropathies.

Nerve conduction velocity (NCV) tests and electromyography (EMG) can help determine the type and extent of nerve damage. Nerve and skin biopsies, autonomic testing, and imaging such as magnetic resonance imaging (MRI) and computed tomography (CT) scans can also provide diagnostic information.

Treatment options for peripheral neuropathy depend on the type of nerve damage and involve managing symptoms and treating any underlying cause. As long as nerve cells have not died, it’s possible for peripheral nerves to regenerate and restore function over time.

If peripheral neuropathy is related to a condition like diabetes or an autoimmune disease, doctors will try to control or treat that condition to manage symptoms, allow nerves to heal, and prevent further damage.

Healthy lifestyle habits—such as eating a balanced diet, exercising, avoiding smoking, and correcting vitamin deficiencies—can promote nerve health and improve symptoms. To help with motor-related symptoms, people may use supportive shoes and braces. Certain medications and alternative treatments like acupuncture and massage can help manage autonomic and sensory symptoms. Cognitive behavioral therapy and other strategies like biofeedback and relaxation therapy may be helpful in coping with neuropathic pain.

Peripheral neuropathy medications are often used to treat other medical conditions, such as depression and epilepsy. These drugs help the brain block pain signals or reduce inappropriate nerve signals. Anesthetics and topical treatments can also help manage pain. In some cases where a nerve is compressed, surgery may be an option to release pressure and allow the nerve to heal.

Current research efforts focus on understanding the genetic mutations that cause neuropathies and the biological mechanisms related to chronic neuropathic pain. Studies also look to identify genetic biomarkers, better understand the regeneration of nerve cell axons, investigate inflammation and autoimmune-related nerve damage, and learn more about how nerves communicate with the brain and muscles. This knowledge can help develop more effective ways to prevent, diagnose, and treat peripheral neuropathies.