Understanding Peripheral Neuropathy – The Basics
“Whatever you cannot understand, you cannot possess”. – Johann Wolfgang von Goethe
Types of Peripheral Neuropathy
There are several kinds of peripheral neuropathy that stem from a variety of causes. They range from carpal tunnel syndrome (an injury common after chronic repetitive use of the hands and wrists, such as computer use) to Guillain-Barre syndrome (a rare, sudden paralysis).
As a group, peripheral neuropathies are common, especially among people over the age of 55. Altogether, the conditions effect 3% to 4% of people in this group.
Neuropathies are typically classified according to the problems they cause of 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.
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.
- Radial nerve palsy is caused by injury to the nerve that runs along the underside of the arm.
- Peroneal nerve palsy results when the nerve at the top of the calf behind the knee is compressed. This leads to a condition called “foot drop”, in which it becomes difficult to lift the front of one or both 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, sex organs and/or intestines. Neuropathy that affects internal organs is called an autonomic neuropathy.
Polyneuropathy accounts for the greatest number of peripheral neuropathy cases. It occurs when many peripheral nerves throughout the body malfunction at the same time. Polyneuropathy can have a wide variety of causes, including exposure to certain toxins, 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 the result of poorly controlled blood sugar levels. Though less common, diabetes can also cause mononeuropathy, often characterized by weakness of the eye or of the thigh muscles.
These are the most common symptoms of polyneuropathy:
- 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.
Joints are particularly vulnerable to stress in people with polyneuropathy because they are often insensitive to pain.
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. Symptoms tend to appear quickly and worsen rapidly, sometimes leading to paralysis. Early symptoms include weakness, tingling, and loss of sensation in the legs that eventually spread to the arms. Blood pressure problems, heart rhythm problems, and breathing difficulty may occur in critical cases. However, despite the severity of the disease, recovery rates are good when patients receive treatment early.