What is neuropathy?
Neuropathy--also called peripheral neuropathy--refers
to any condition that affects the normal activity of the nerves of the
peripheral nervous system. The peripheral nervous system is the network of
nerves that connects the central nervous system--the brain and spinal cord--to
the rest of the body.
The peripheral nervous system is made up of three
types of nerves, each with an important role to play in keeping your body
healthy and functioning properly.
- Sensory nerves carry messages from your senses through your spinal
cord to your brain. For example, they tell your brain you are touching something hot.
- Motor nerves travel in the opposite direction. They carry messages
from the brain to your muscles. They tell your muscles to move you away from the hot surface.
- Autonomic nerves are responsible for controlling body functions that
occur outside our control, such as breathing, digestion, heart rate, and blood pressure.
Neuropathy results when nerve cells, or neurons, are
damaged or destroyed. This distorts the way the neurons communicate with each
other and with the brain. Neuropathy can affect one nerve or nerve type, or a combination of nerves.
What causes neuropathy?
There are many causes of neuropathy. The cause can be
hereditary (runs in families) or acquired (develops after birth).
Hereditary neuropathy
The most common hereditary neuropathy is Charcot-Marie-Tooth
(CMT) disease, which affects both motor and sensory nerves. CMT affects about
one in 2,500 people in the United States. CMT causes weakness in the foot and
lower leg muscles. Deformities of the feet are also common, making it difficult
to walk and often resulting in falls. In its later stages, CMT can also affect
the muscles in the hands. There is no cure for hereditary neuropathy.
Acquired neuropathy
Acquired neuropathy is much more common. There are many causes of acquired neuropathy, including:
- Trauma — This includes sudden injury from an event such as a fall,
car accident or sports activity. Trauma to the peripheral nerves can also
occur from compression of the nerves due to repetitive stress or narrowing of the nerve space.
- Infections and autoimmune disorders — Among the germs that can
damage nerve fibers are human immunodeficiency virus (HIV), the herpes
virus, and the bacteria that cause Lyme disease and syphilis. Some
autoimmune disorders can also affect nerve tissue. Examples include
Guillain-Barré syndrome, systemic lupus erythematosus, and rheumatoid arthritis.
- Systemic diseases — Systemic diseases are those that affect the
entire body. These include diabetes--the leading cause of peripheral
neuropathy--kidney disorders, certain cancers, and hormonal imbalances.