High levels of glucose can attack any nerve in the body, impairing its function. The exact way that the nerve gets damaged is unclear, but several possibilities may be important. Once glucose gets into the nerve in high concentrations (because the blood level of glucose is high), it can bind to important proteins and enzymes affecting their function. Also, high concentrations of glucose in the nerve may draw water into the cell, swelling it and affecting concentrations of other key chemicals. Blood and oxygen supply to the nerve may be improtant. Whatever the cause, the end result is that the nerve gets damaged. How this affects the individual depends on what nerves are affected.
The most common neuropathy (i.e. something wrong with a nerve) is "peripheral neuropathy", meaning a problem at the periphery of the body, such as the ends of the feet and hands. Common symptoms are numbness, a "pins-and-needles" feeling (as if the feet have fallen "asleep"), burning, and a feeling like an electric shock. However, a person will usually not feel any symptoms at all.
Peripheral neuropathy is dangerous. Individuals with it can injure their foot and not know it. This leads to foot infections, a dreaded complication of diabetics as it often leads to amputation. People who realize they have something wrong with their sensation can use this knowledge, and guard themselves by protecting their feet from injury. Individuals should examine their feet daily for any unnoticed injury, and keep the feet clean and moisturized. This will reduce the risk of significant problems. People who arent aware of any problem must be informed by their doctor so they can be on guard. Nevertheless, it never hurts to assume that sensation of the feet is not normal, and take especially good care of the feet.
Another problem with a peripheral neuropathy is pain, which can be severe. It is usually worse in the evening or night, and can be particularly bothersome because it interferes with sleep. It drives some people to take narcotics for relief, to which they inevitably become addicted. Never try narcotics for this pain; many options for pain relief are available, but all are medications that must be prescribed by your doctor. They work by altering the chemistry within the nerve, particularly that which causes pain. These drugs include some of the older anti-depressants (in small doses), anti-seizure medications, and drugs that are sometimes used for rhythm disturbances of the heart. Creams containing capsaicin also help certain individuals. Any of these treatments take weeks to have an initial effect.
There are other problems with these neuropathies. As they get severe, one cannot sense the floor against the foot, making even walking difficult. People usually interpret this as having lost their balance. When sensation of the fingers is poor, everyday tasks become difficult or impossible. Things we normally take for granted fastening a button, pulling up a zipper, tying a tie depend upon our being able to feel with our fingers. Even holding objects may be difficult.
Weakness and unsteadiness of the arms or legs can be a problem. When severe, the muscles of the hands waste away and the ability to use the fingers is impaired. Without nerves to supply it, muscle is lost from the foot, leading to certain deformities, calluses and ulcers, and sometimes even amputation.
Any nerve can be affected adversely by high blood sugars. Any kind of nerve compression, such as carpal tunnel, sciatica, and others, is more common in people with diabetes, probably because a nerve that has too much glucose is more susceptible to injury by compression.
There are instances where nerves to the large muscles of the legs can be predominantly affected. This can cause pain and severe tenderness.
Diabetes can also affect nerves that we are normally unaware of, including those which keep our internal organs functioning correctly. This causes a large variety of problems, such as:
"Diabetic Gastroparesis" occurs when diabetes affects the nerves that supply the stomach. This causes the muscles in the stomach to stop working, resulting in a very flaccid stomach that doesnt move food very well. Food sits in the stomach for many hours, undigested. Sooner or later, the individual gets nauseated and vomits.
Gastroparesis also makes it harder to control blood sugars because you never know when the food you eat is going to be absorbed resulting in blood sugars that are either too high or too low, and rarely in between. Medications may help, if the disease is mild enough.
If the nerves to the large intestine are affected, individuals will usually experience diarrhea. This is especially bothersome because it typically occurs during the night, and can be associated with incontinence. Indeed, the individual can have a bowel movement in bed and not realize until it is too late. This is because the rectum has lost sensation; without being able to sense when there is stool present, the individual does not know to go to the toilet. Again, medications may help this symptom.
When the nerves to the bladder are affected, the bladder loses some of its muscle tone, and acts more like a flaccid bag, unable to contract or push. This results in incomplete emptying of the bladder, predisposing the individual to infections and other problems. Urination may consist merely of spill-over from the bladder, rather than proper contraction of the bladder muscle. This too can be helped somewhat by medication, although the most severe cases require intermittent catheterization of the bladder (putting a soft tube in the bladder to help it drain).
Nerves to the heart affect heart rate, and disease of these nerves generally affects the ability of the heart to control its heart rate. People with this kind of neuropathy generally have heart rates that are faster than normal.
When diabetes afflicts the heart nerves, the sensation of what is going on in the heart is blunted. This is dangerous for someone with some degree of coronary artery disease (hardening of the arteries to the heart). Lacking oxygen, the heart feels pained, a condition called angina. But a diabetic may not feel anything, or realize anything is wrong. His actions at the time will not be changed, and this could precipitate a heart attack, or worse.
Nerves to the blood vessels and heart affect the maintenance of adequate blood pressure when we change positions, such as getting up from a lying position to a standing position. If these nerves are affected, the individual may become dizzy anytime he stands up, and may even black out.
Diabetes is a common cause of impotence, though it is typically overlooked. This, too, is a manifestation of the nerves being affected, in this case, the nerves to the penis. There are a number of options to help this symptom please ask your doctor or educator for more information. Diabetes can interfere with a womans sexual performance and pleasure as well, by impairing lubrication and other problems. Research is quite lacking in this area.
Doctors probably overlook this diagnosis in most cases, because they dont ask