Understanding Peripheral Neuropathy -- the Basics
The most common symptoms of polyneuropathy are:
- Loss of sensation in the arms and legs
Because people with chronic polyneuropathy often lose their ability to sense temperature and pain, they can burn themselves and develop open sores as the result of injury or prolonged pressure. If the nerves serving the organs are involved, diarrhea or constipation may result, as well as loss of bowel or bladder control. Sexual dysfunction and abnormally low blood pressure also can occur.
One of the most serious polyneuropathies is Guillain-Barre syndrome, a rare disease that strikes suddenly when the body's immune system attacks nerves in the body just as they leave the spinal cord. Symptoms tend to appear quickly and worsen rapidly, sometimes leading to paralysis. Early symptoms include weakness and tingling that eventually may spread upward into the arms. Blood pressure problems, heart rhythm problems, and breathing difficulty may occur in the more severe cases. However, despite the severity of the disease, recovery rates are good when patients receive treatment early.
What Causes Peripheral Neuropathy?
There are many factors that can cause peripheral neuropathies, so it is often difficult to pinpoint the origin. Neuropathies occur by one of three methods:
Acquired neuropathies are caused by environmental factors such as toxins, trauma, illness, or infection. Known causes of acquired neuropathies include:
- Several rare inherited diseases
- Poor nutrition or vitamin deficiency
- Certain kinds of cancer and chemotherapy used to treat them
- Conditions where nerves are mistakenly attacked by the body’s own immune system or damaged by an overaggressive response to injury
- Certain medications
- Kidney or thyroid disease
- Infections such as Lyme disease, shingles, or AIDS
Hereditary neuropathies are not as common. Hereditary neuropathies are diseases of the peripheral nerves that are genetically passed from parent to child. The most common of these is Charcot-Marie-Tooth disease type 1. It is characterized by weakness in the legs and, to a lesser degree, the arms -- symptoms that usually appear between mid-childhood and age 30. This disease is caused by degeneration of the insulation that normally surrounds the nerves and helps them conduct the electrical impulses needed for them to trigger muscle movement.
Idiopathic neuropathies are from an unknown cause. As many as one-third of all neuropathies are classified in this way.