Peripheral nerve injuries

Overview

A peripheral nerve injury happens when one of the nerves located outside the brain or spinal cord is damaged. These nerves connect the brain and spinal cord to the rest of the body. They carry messages that control movement and allow the body to feel things such as temperature, pain or touch. Peripheral nerves are made of fibers called axons. These fibers are protected by surrounding tissues.

Peripheral nerves are fragile, and they damage easily. A nerve injury can make it hard for the brain to communicate with muscles and organs. Damage to the peripheral nerves is called peripheral neuropathy.

It's important to get medical care for a peripheral nerve injury as soon as possible. Early diagnosis and treatment may prevent complications and lasting damage.

Symptoms

With a peripheral nerve injury, signs and symptoms may range from mild to serious. Your daily activities may be limited. Symptoms often depend on which nerve fibers are damaged:

• Motor nerves. These nerves control all the muscles under your conscious control. They include muscles for walking, talking and holding objects. Damage to these nerves can cause muscle weakness, painful cramps and muscle twitching.
• Sensory nerves. Because these nerves relay information about touch, temperature and pain, you may have many different symptoms. These may include numbness or tingling in the hands or feet. You may have trouble walking, keeping your balance with your eyes closed, fastening buttons, or sensing pain or changes in temperature. Injury of sensory nerves also may cause pain.
• Autonomic (aw-tuh-NOM-ik) nerves. This group of nerves controls activities that are not controlled consciously. For instance, these nerves control breathing, heart and thyroid function, and digestion. Symptoms may include heavy sweating, changes in blood pressure, gastrointestinal issues and not being able to handle heat. Damage to the autonomic nerves is called autonomic neuropathy.

Many peripheral nerve injuries affect more than one type of nerve fiber, so you may have a range of symptoms.

When to see a doctor

If you have weakness, tingling, numbness or a total loss of feeling, see a healthcare professional to find out the cause. It's important to treat peripheral nerve injuries early.

Causes

Damage to peripheral nerves can happen in different ways:

• An accident, a fall or sports can stretch, compress, crush or cut nerves.
• Certain medical conditions can damage nerves, such as diabetes, Guillain-Barre syndrome and carpal tunnel syndrome.
• Autoimmune diseases also can damage nerves, including lupus, rheumatoid arthritis and Sjogren syndrome.

Other causes include narrowing of the arteries, changes in hormone balance and tumors.

Risk factors

People who have physical trauma or play sports may be at higher risk of an injury that stretches or crushes peripheral nerves. People with certain medical conditions also may be at higher risk of peripheral nerve injuries. These conditions, especially diabetes, may raise the risk of nerves being compressed.