The Nerve Damage of Diabetes
What Causes Diabetic Neuropathy? continued...
How high blood glucose leads to nerve damage
is a subject of intense research. The precise mechanism is not known.
Researchers have discovered that high glucose levels affect many metabolic
pathways in the nerves, leading to an accumulation of a sugar called sorbitol
and depletion of a substance called myoinositol. However, studies in humans
have not shown convincingly that these changes are the mechanism that causes
More recently, researchers have focused on
the effects of excessive glucose metabolism on the amount of nitric oxide in
nerves. Nitric oxide dilates blood vessels. In a person with diabetes, low
levels of nitric oxide may lead to constriction of blood vessels supplying the
nerve, contributing to nerve damage. Another promising area of research centers
on the effect of high glucose attaching to proteins, altering the structure and
function of the proteins and affecting vascular function.
Scientists are studying how these changes
occur, how they are connected, how they cause nerve damage, and how to prevent
and treat damage.
What Are the Symptoms of Diabetic Neuropathy?
The symptoms of diabetic neuropathy vary. Numbness and tingling in feet are
often the first sign. Some people notice no symptoms, while others are severely
disabled. Neuropathy may cause both pain and insensitivity to pain in the same
person. Often, symptoms are slight at first, and since most nerve damage occurs
over a period of years, mild cases may go unnoticed for a long time. In some
people, mainly those afflicted by focal neuropathy, the onset of pain may be
sudden and severe.
What Are the Major Types of Neuropathy?
The symptoms of neuropathy also depend on which nerves and what part of the
body is affected. Neuropathy may be diffuse, affecting many parts of the body,
or focal, affecting a single, specific nerve and part of the body.
The two categories of diffuse neuropathy are peripheral neuropathy affecting
the feet and hands and autonomic neuropathy affecting the internal organs.
The most common type of peripheral neuropathy
damages the nerves of the limbs, especially the feet. Nerves on both sides of
the body are affected. Common symptoms of this kind of neuropathy
- Numbness or insensitivity to pain or temperature
- Tingling, burning, or prickling
- Sharp pains or cramps
- Extreme sensitivity to touch, even light touch
- Loss of balance and coordination
- These symptoms are often worse at night
The damage to nerves often results in loss of
reflexes and muscle weakness. The foot often becomes wider and shorter, the
gait changes, and foot ulcers appear as pressure is put on parts of the foot
that are less protected. Because of the loss of sensation, injuries may go
unnoticed and often become infected. If ulcers or foot injuries are not treated
in time, the infection may involve the bone and require amputation. However,
problems caused by minor injuries can usually be controlled if they are caught
in time. Avoiding foot injury by wearing well-fitted shoes and examining the
feet daily can help prevent amputations.