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How familiar are you with nerves? Believe it or not, there are over 7 trillion nerves in the human body. Together, they make up the nervous system, which is responsible for transmitting signals from the brain throughout the body and vice-versa. Certain conditions or accidents can damage nerves, which affects how you feel and function. Peripheral nerve damage can be categorized into three main types: neuropraxia, axonotmesis, and neurotmesis. Each type represents a different level of injury to the nerves. If you have never heard of these words before today - don't worry! PatientsLikeMe is here with a guide.
Neuropraxia
Neuropraxia is the mildest form of nerve injury. Think of it as a Grade I injury. Your peripheral nerves are the ones that sit outside of your brain and spinal cord. Neuropraxia is an injury to these peripheral nerves. It can happen to anyone, and may come after an injury like a fall or car accident. It is particularly common in people who play contact sports. In this type of damage, the nerve stays intact but impulses cannot get through to the injured part of the body. This can lead to a variety of symptoms:
- Burning
- Numbness
- Stinging
- Weakness
Fortunately, neuropraxia does not typically lead to long term damage. Nerves usually recover on their own within a few weeks. Treatment consists of following the RICE protocol (rest, ice, compression and elevation) and stabilization of the injured area with braces or splints. Doctors may also recommend taking pain medication or going to physical therapy.
Axonotmesis
Axonotmesis, also known as nerve crush injury, is a more serious type of nerve damage compared to neuropraxia - think Grade II. In neuropraxia, there is a blockage of the nerve. In axonotmesis, the axons and their myelin sheaths are physically damaged. Axons are a part of the neuron that extend out and connect to other neurons. They are the "output" part of the cell. The myelin sheath is the layer than protects the neuron. In neuropraxia, the signal was unable to travel along the neuron because of an injury, but the neuron itself was not damaged. In axonotmesis, the neuron is damaged. This usually is the result of a more severe injury, particularly a crush or stretch injury. Symptoms can include:
- Numbness or tingling
- Muscle weakness
- Loss of feeling
- Pain
Fortunately nerve fibers can regrow, which can take a long time. In adults, nerves regrow at about 1 inch per month. Infants might recover faster because their nerves can regrow more quickly and the distance to be covered is shorter. Scar tissue can hinder regrowth. Timely intervention is crucial because muscle receptors for nerves can disappear over time. Doctors may turn to surgery to help the nerve heal. Physical or occupational therapy are also common.
Neurotmesis
Neurotmesis is the most severe type of nerve damage. This is a Grade III injury to the peripheral nervous system. The root of the word, "tmesis," is from Greek for "to cut." In neurotmesis, both the nerve and the nerve sheath are severed, and full recovery is unlikely. This can come about from cuts, car accidents, dislocations, or sports injuries. It most commonly happens in the arms, which account for about 73% of all cases. A severed nerve can lead to Wallerian degeneration. This is an active process your body goes through when a nerve is severed. Over the following few weeks, the rest of the nerve will degenerate, making recovery impossible. Symptoms of neurotmesis include:
- Pain
- An uncomfortable sensation in the affected area
- Loss of sensory and motor function
There is no chance of spontaneous recovery. Early surgical intervention is needed to try and repair the nerve. External neurolysis is the most common approach, which is when surgeons remove tissue around the affected nerve and try to straighten and realign it. However, even with surgery, recovery may not be possible depending on the damage. Doctors will typically try to treat the pain first through medication.
So there you have it. The three classifications of peripheral nerve damage, how they affect you, and what the treatment options are. The nervous system is complex! Pain is complex. Understanding what goes on in our bodies is the best way to take charge of our health. Be sure to check out PatientsLikeMe for more information and support.