Understanding Peripheral Neuropathy -- the Basics
Here are examples of other mononeuropathies that can cause weakness in the affected parts of the body, such as hands and feet:
- Ulnar nerve palsy occurs when the nerve that passes close to the surface of the skin at the elbow is damaged. The numbness is noted in the 4th and 5th digit of the hand.
- Radial nerve palsy is caused by injury to the nerve that runs along the underside of the arm and can occur with fractures of the bone in the upper part of the arm.
- Peroneal nerve palsy results when the nerve at the top of the calf on the side of the knee is compressed. This leads to a condition called "foot drop," in which it becomes difficult to lift the feet.
Neuropathy can affect nerves that control muscle movement (motor nerves) and those that detect sensations such as coldness or pain (sensory nerves). In some cases, it can affect internal organs, such as the heart, blood vessels, bladder, or intestines. Neuropathy that affects internal organs is called an autonomic neuropathy. This rare condition can cause low blood pressure or problems with sweating.
Polyneuropathy accounts for the greatest number of peripheral neuropathy cases. It occurs when multiple peripheral nerves throughout the body malfunction at the same time. Polyneuropathy can have a wide variety of causes, including exposure to certain toxins such as with alcohol abuse, poor nutrition (particularly vitamin B deficiency), and complications from diseases such as cancer or kidney failure.
One of the most common forms of chronic polyneuropathy is diabetic neuropathy, a condition that occurs in people with diabetes. It is more severe in people with poorly controlled blood sugar levels. Though less common, diabetes can also cause a mononeuropathy.
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.