Understanding Peripheral Neuropathy -- the Basics
What Is Peripheral Neuropathy?
The name of the condition tells you a bit about what it is:
Peripheral: Beyond (in this case, beyond the brain and the spinal cord.)
Neuro-: Related to the nerves
Peripheral neuropathy refers to the conditions that result when nerves that carry messages to the brain and spinal cord from the rest of the body are damaged or diseased.
The peripheral nerves make up an intricate network that connects the brain and spinal cord to the muscles, skin, and internal organs. Peripheral nerves come out of the spinal cord and are arranged along lines in the body called dermatomes. Typically, damage to a nerve will affect one or more dermatomes, which can be tracked to specific areas of the body. Damage to these nerves interrupts communication between the brain and other parts of the body and can impair muscle movement, prevent normal sensation in the arms and legs, and cause pain.
Types of Peripheral Neuropathy
There are several different kinds of peripheral neuropathies that stem from a variety of causes. They range from carpal tunnel syndrome (a traumatic injury common after chronic repetitive use of the hands and wrists, such as with computer use) to nerve damage linked to diabetes.
As a group, peripheral neuropathies are common, especially among people over the age of 55. All together, the conditions affect 3% to 4% of people in this group.
Neuropathies are typically classified according to the problems they cause or what is at the root of the damage. There also are terms that express how extensively the nerves have been damaged.
Damage to a single peripheral nerve is called mononeuropathy. Physical injury or trauma such as from an accident is the most common cause. Prolonged pressure on a nerve, caused by extended periods of being sedentary (such as sitting in a wheelchair or lying in bed), or continuous, repetitive motions, can trigger mononeuropathy. If the fibrous, shock-absorbing discs that lie between the bones in the back are damaged, they could press on a nerve and cause this type of neuropathy.
Carpal tunnel syndrome is a common type of mononeuropathy. It is called an overuse strain injury, which occurs when the nerve that extends through the wrist is compressed. People whose work requires repeated motions with the wrist extended (such as assembly-line workers, physical laborers, and those who use computer keyboards for prolonged periods) are at greater risk.
The damage to the nerve can result in numbness, tingling, unusual sensations, and pain in the first three fingers on the thumb side of the hand, particularly while sleeping. In time, carpal tunnel injuries can weaken the muscles in the hand. You may also feel pain, tingling, or burning in your arm and shoulder.