Nerves are bundles of fibers covered by insulation (similar to an electrical cable) that send information from the brain to the spinal cord and then to the rest of your body, and from your body back to the spinal cord and brain.
Nerves can be damaged in an injury. Depending on the cause and severity of the damage, people with nerve damage can experience a combination of nerve pain, burning, tingling, weakness, and loss of sensation in the affected body part.
Sometimes nerve damage can get better on its own, or with treatments like physical therapy. More severe injuries may require surgery. If you suspect you have nerve damage, see your doctor.
Types of nerves
The body has two nervous systems: the central nervous system and the peripheral nervous system. The central nervous system is composed of the brain and spinal cord. The peripheral nervous system includes the nerves that branch out from the brain and spinal cord and extend to other parts of your body (your arms, legs, face, chest, and abdomen to name a few). Nerve damage generally refers to the peripheral nervous system.
There are two main parts of the peripheral nervous system. The somatic nervous system is responsible for voluntary movement, and the autonomic nervous system controls involuntary activity.
Part of the somatic nervous system, motor nerves (also known as the efferent nervous system) send signals from the brain and spinal cord to the rest of the body to control movement.
Part of the somatic nervous system, sensory nerves (known as the afferent nervous system) send signals back to the brain and spinal cord from the rest of the body.
The autonomic nervous system controls all of the important tasks in our body that occur without us even thinking about them, like controlling our heartbeat, blood pressure, and digestion.
Symptoms of peripheral nerve damage depend on the severity of the injury and the type and location of the nerve injured. Some signs of nerve damage include:
- Pins-and-needles sensation
- Sensitivity to touch
Severe injuries can also cause total loss of sensation or movement of the affected body part. In situations where the injury becomes chronic or long lasting, severe nerve pain or problems with muscle shrinking (called atrophy) can also occur.
How long damaged nerves take to heal is variable, depending on the type of injury and where along the nerve the injury occurs. Peripheral nerves regenerate and heal at approximately 1 mm/day. A more mild injury can recover within days to weeks, but severe injury that requires regeneration of all layers of the nerve can take months to years to reach maximum improvement. —Dr. Karen Hoerst
Peripheral nerves are made up of many axons, which are like long, thin wires that carry electrical signals between the body and the brain. Our nerves are surrounded by multiple layers of protective connective tissue, including the myelin sheath, the endoneurium, the perineurium, and the epineurium.
Nerve damage occurs when any of these components are injured and electrical signals cannot properly travel through the body.
These injuries can be caused by pressure, complete severing or tearing, or irritation to a nerve. They can happen from being in a car accident or experiencing a deep cut that hits a nerve.
But there are more subtle ways to injure nerves, such as compression of a nerve from poor posture (such as hunching over a keyboard) or crossing your legs for too long. Fortunately, these types of injuries are often temporary and the damage can usually be reversed quickly.
Some causes include:
- A cut or tear in the nerve tissue
- Crush injury
- Compression/pressure injury
- Bruising or swelling of the nerve or near the nerve
- Gunshot wounds
- Stretching injury
- Electrical injury (mechanical and chemical burns)
- Irritation or inflammation of the nerve such as in Bell’s Palsy
Some types of nerve injury do not require medical workup. The classical example is when you cross your legs for too long and get pins and needles in that leg. If the symptoms go away quickly and it doesn’t happen often, you do not need to see your doctor.
But if the same type of symptom occurs and does not immediately improve, there may be mild damage to the nerve and you should see a doctor.
Your doctor will determine if you need tests to see how well the nerve is conducting electrical signals. These tests are called electromyography and nerve conduction velocity tests. You may also be referred to a neurologist for additional testing.
Your doctor might use a combination of the results of your tests to rate the nerve damage. One grading system described by the American Academy of Physical Medicine and Rehabilitation ranges from first to fifth degree nerve injury. They are based on the number of protective layers of the nerves that are damaged and the level of injury. The categories are:
One of the more common nerve injuries is called Saturday night palsy. It occurs after falling asleep with an arm draped across the arm of a chair (typically after drinking too much alcohol), leading to nerve damage from pressure on the radial nerve. It can take weeks to months for this to improve. —Dr. Hoerst
First degree: Called neuropraxia, this is the mildest form of peripheral nerve damage. It’s caused by an injury to the covering or insulation of the nerve (myelin) that temporarily blocks the nerve from conducting electrical signals. An example is someone who falls asleep with their arm draped over a chair for an entire night, pressing on a nerve. In many cases, this will improve over the course of a few days.
Second degree: The axon is damaged or injured, but the endoneurium (the protective layer around the axon) is intact. In this case, the nerve’s ability to conduct electrical signals is interrupted. You may be able to heal without surgery but recovery takes longer than neuropraxia.
Third degree: These injuries damage the axon and endoneurium. Nerve conduction is impaired. It’s difficult to predict whether the affected nerve will recover from a grade 3 injury, and surgery is often needed.
Fourth degree: This level of injury involves damage to the axons and all of the surrounding protective layers (endoneurium, perineurium, epineurium.) It causes scarring. No electrical energy can be passed along the nerve and surgery is necessary to repair it.
Fifth degree: This type of injury involves complete transection of the nerve, meaning the nerve has been split in two.
The recommended treatment depends on the cause and grade of the injury. If you need surgery, the ultimate goal is to restore function to the body part affected by the damaged nerve.
Your doctor may give you a prescription medication such as gabapentin that can treat painful tingling and other symptoms related to numbness in the hands. If your symptoms are caused by a specific type of inflammation, for example the facial nerve in Bell’s palsy, other medications like steroids or antivirals may be used.
More severe injuries may require peripheral nerve surgery, which is performed by a neurosurgeon. The type of surgery depends on the cause and the severity of the injury.
Some surgeries, such as carpal tunnel release, may be done in the doctor’s office with local numbing medications. Other more complicated surgeries would be performed in a hospital under general anesthesia.
Physical or massage therapies
Your doctor may recommend physical therapy or massage therapy to improve nerve function and regain strength that you may have lost by the injury.
Physical therapy and occupational therapy may also be helpful to improve your range of motion and posture and teach strategies to prevent further injury caused by compression. For example, people with mild carpal tunnel syndrome can learn certain hand and wrist exercises and wear a wrist brace to prevent it from worsening.
Eating a well-balanced diet
Fruits, vegetables, whole grains, and lean proteins can provide your body with the nutrition necessary to maintain nerve health.
Regular activity can help prevent and also control metabolic diseases such as obesity and diabetes. While exercise mainly helps prevent nerve damage, if you are experiencing nerve damage from being overweight, exercise and weight loss may reduce your symptoms.
Treatment of other medical conditions
In some instances, other illnesses may contribute to nerve damage. For example, people with diabetes or thyroid disease are at an increased risk of nerve problems. Treating these conditions can help improve and prevent symptoms.
Some of the ways to know that nerve damage is healing can be common sense. If you have weakness that is getting better, this obviously means there has been improvement. However, other signs that may indicate improvement are less clear. For example, if you had no sensation to a part of the body, but then experience mild pain or tingling, this might be a sign that the nerves are starting to send signals and are healing. —Dr. Hoerst
Even if you don’t need surgery, it’s important to have follow-up visits with your doctor so they can see if you’re healing properly. For first and second degree injuries, your doctor will usually ask you to follow up in 4 to 6 weeks to see that your symptoms are improving (if they haven’t disappeared already).
If you had surgery, your doctor will give you a follow-up plan. The timing of follow-up visits depends on your level of injury. Most surgeons will ask you to follow up 1 to 2 weeks after surgery. After that, they’ll recommend additional follow-up visits at regular intervals to evaluate improvement in your symptoms.
You may be able to prevent some forms of nerve damage with simple lifestyle changes such as:
- Avoid repetitive motions or cramped positions that put unnecessary pressure on your nerves.
- Be careful when lifting heavy objects or using sharp objects and tools.
- Use correct form when exercising, especially when lifting heavy amounts of weight.
- Improve your posture. Try a support for your back when typing and take breaks throughout the day to lessen compression and irritation of the nerves in your arms and shoulders.
Dr. Gambrah-Lyles is a resident pediatrician at the Children's Hospital of Philadelphia. She is a graduate of the University of Pennsylvania Perelman School of Medicine (2019). She graduated cum laude and received her undergraduate degree in Biochemistry and Spanish from Washington University in St. Louis (2013). Her research explores the intersections between neurology, public health, and infectious disease. She has investigated nutrition and cerebral palsy in Botswana, and completed a year-long project in Brazil, researching growth and developmental outcomes of Zika virus infection in pediatric patients as a Doris Duke International Scholar. Dr. Gambrah-Lyles speaks four languages, loves staying active, and enjoys sharing her love for medicine through teaching and writing.