With more than 20 million sufferers in the United States, peripheral neuropathy is possibly the most common disease you've never heard of. Any nerve not in the brain or spinal cord is a peripheral nerve. These nerves send information from your brain and spinal cord (central nervous system) to the rest of our body. Any disease or disorder of the peripheral nerves is called peripheral neuropathy.
TYPES OF NEUROPATHY AND NERVES
Peripheral neuropathy is broken down into the following categories:
- Motor neuropathy – This is damage to the motor nerves that control muscles and movement in the body, such as moving your hands or talking. Motor neuropathy may cause impaired balance and coordination or, most commonly, muscle weakness.
- Sensory neuropathy – Sensory nerves control what you feel, such as pain, temperature or a light touch. Sensory neuropathy may cause numbness to touch and vibration, reduced position sense causing poorer coordination and balance, or pain from normally nonpainful stimuli, such as a light touch.
- Autonomic nerve neuropathy – Autonomic nerves control functions that you are not conscious of, such as blood pressure, bladder function, and the reduced ability to sweat normally.
Peripheral neuropathy can affect one nerve group, two groups, or all three. Sometimes it will affect one nerve only, and that’s called “mononeuropathy”. When the affected nerves are roughly in the same area on both sides of the body it is called “symmetrical polyneuropathy” or simply “polyneuropathy”.
NERVE FIBERS
Nerves are composed of bundles of transmission lines called axons. Some axons in the nervous system are covered in a layer of fatty insulating substance, called myelin. And other axons do not have a myelin covering, or sheath.
Nerve fibers are classed into three types – group A nerve fibers, group B nerve fibers and group C nerve fibers. Groups A and B are large and myelinated, and group C are smaller and unmyelinated.
Some peripheral neuropathies affect the small, unmyelinated nerve fibers of group C and are called small fiber neuropathy. Other neuropathies predominately involve the large myelinated nerves of group A and B and are called large fiber neuropathy.