Researchers aren’t exactly sure what causes diabetic neuropathy, although they have some clues. The biggest clue is that diabetic neuropathy is influenced by blood glucose levels and control.
In 1993, a major study was published in The New England Journal of Medicine that showed that controlling blood glucose levels can help prevent diabetes complications, such as neuropathy. That study very conclusively showed intensive insulin therapy to control blood glucose levels led to lower rates of diabetes complications; this was a long-term study done over the span of nearly seven years1.However, researchers don’t entirely understand how elevated blood glucose levels affect the nerves; they just know that there seems to be a connection between poor glucose control and the development of diabetic neuropathy.
It’s possible that elevated blood glucose levels damage the tiny blood vessels that lead to the nerves. If the blood vessels are damaged, they don’t bring oxygen and nutrients to the nerves as they should, which eventually can cause nerve damage.There are some other factors that may lead to the development of diabetic neuropathy:
- Age: Diabetic neuropathy takes time to develop, so it’s much more common in older people who have had diabetes for 25 years or more.
- Lifestyle choices: It seems that alcohol and smoking make the symptoms of neuropathy worse.
- Nerve injury: Whether your nerves have been damaged through inflammation or through a mechanical injury (such as nerve compression associated with carpal tunnel syndrome), it’s possible the previously-damaged nerves are more susceptible to developing diabetic neuropathy.
However the nerves get damaged, the end result is the same: they aren’t able to convey messages as well as they should to the brain, and they lose their ability to help you feel and move.To diagnose diabetic neuropathy (also called diabetic nerve pain), your doctor will run through several exams and tests. These will all be used to help the doctor understand what nerves have been damaged and how extensive that damage is.
History
Your doctor will review your symptoms with you; this is the first step in trying to figure what kind of nerve damage you may have.The different types of diabetic neuropathy affect different nerves, so you should be very specific when describing your pain or other symptoms.
Physical and Neurological Exams
During a physical exam, the doctor looks at your general physical condition. He or she will examine how well you can move. The doctor will also be looking for tender, sore, or painful areas. The physical exam allows the doctor to assess how your body is doing right now, so he or she will also check blood pressure, heart rate, and other basic health details.
As part of the physical exam, your doctor should thoroughly examine your feet, particularly if you have symptoms that line up with peripheral diabetic neuropathy. (In fact, people with diabetes should have regular foot exams to monitor foot health.)
Since diabetic neuropathy involves the nerves, the neurological exam is a crucial part of the diagnosis. This is where he/she may test your “sensations”—how well you’re able to feel certain stimuli—which is especially important in diagnosing peripheral diabetic neuropathy.Different nerves are in charge of transmitting different sensory messages, such as temperature, touch, and vibration. Damaged nerves can’t transmit messages as well as they should, so these tests can be very helpful in narrowing down which nerves are affected.
Some possible sensation tests are:
- Temperature: The doctor will hold a very hot or very cold object near your skin to test how well you can feel temperature.
- Touch: He or she may actually prick you with a pin to see how well your touch nerve fibers are working. These are the fibers that not only tell you when you’ve come into contact with something, but they also tell you when you’ve been hurt (e.g., developed a sore or blister, or stepped on a shard of glass).
- There is another way to test the touch nerves. The doctor may use a bendable nylon filament to test how much pressure you can feel. There are different-sized filaments that require different amounts of pressure to bend. By pushing a filament against the skin—on the foot, say—the doctor can measure how much force you can feel.
- If you can feel a thin filament, then you can feel anything that touches your skin. If you can’t feel when a thicker filament is pushed against your skin, you probably have some degree of nerve damage.
- Vibration: Using a tuning fork, the doctor will test how well you can feel vibrations. The vibration nerves are important for balance.
Diagnostic Tests
The doctor may need to do some simple diagnostic tests to check how well the nerves are conveying messages. Nerve conduction velocity (NCV) is how fast nerve impulses travel, and it’s possible to measure that. Sometimes, noticing a slower NCV is the first sign of diabetic neuropathy because if nerves are damaged, they don’t convey messages as quickly.
Many conditions other than diabetes can cause neuropathy. Because other causes may need to be treated differently than diabetic neuropathy, it is important to do nerve testing in order to know for sure what type(s) of nerve pain you have.
An NCV test is done using electrodes that are patched onto the skin. These are placed along a nerve pathway—one at the top of the leg and one further down, for example. A tiny electrical current stimulates the nerve at one electrode, and then the second electrode captures the signal as it passes down the nerve. The test measures how long it took the signal to travel down the nerve.
An electromyography (EMG) test is often done in conjunction with an NCV test. It shows how well muscles are receiving signals from the nerves. Damaged nerves won’t send clear or consistent messages.
The EMG test uses very thin needles placed into the muscle(s) the doctor wants to test. Those needles are electrodes that measure activity. You’ll have to contract your muscles, and then that activity will be measured. If the muscle isn’t receiving good signals from the nerves, then that should show up on the EMG.
Other Possible Tests
Your doctor may run other tests not listed here—based on your specific symptoms and the type of diabetic nerve pain he or she thinks you have.
All tests will help the doctor pinpoint what kind of nerve damage you have, how it’s affecting your body, and how it can best be treated.
The best way to treat diabetic neuropathy (also called diabetic nerve pain) is to keep tight control on your blood glucose levels. This is, in fact, the only way to slow the progression of nerve damage. Out-of-control blood glucose levels cause diabetic neuropathy, so it makes sense that keeping your blood glucose in an acceptable range can help you avoid nerve damage or stop it from getting worse.
You are familiar with the drill of how to control your blood glucose: eat right, exercise, take your diabetes medication, and monitor your blood sugar (blood glucose) levels throughout the day.
Eat Right
Your doctor and/or diabetes educator will help you figure out a healthy diet that works for you-one that makes it easier to control your blood glucose and keep your hemoglobin A1c in the correct range. (To learn more about the hemoglobin A1c level—sometimes called the glycosylated hemoglobin or glycol hgb—please see below. With full awareness of the carbohydrates, fat, and protein in your diet, you'll be better able to avoid severe swings from hypoglycemia to hyperglycemia. You'll also be able to better maintain a healthy weight.
Exercise
Exercise can lower your blood glucose level, and it should make it easier to control it. In fact, exercise increases your insulin sensitivity: after you exercise, you don’t need as much insulin to help process carbohydrates.
Additionally, there are all the traditional benefits of exercise:
Diabetes Medication—Including Insulin
Insulin is a hormone that’s normally produced by the body, but for people with diabetes, it’s either not working as it should (the case in type 2 diabetes) or the body has stopped making it (type 1 diabetes).
People with diabetes may need to take insulin to keep their blood glucose levels in a healthy range—important for preventing diabetic neuropathy.
Insulin helps your body use glucose appropriately. You can read all about the role of insulin in this article that explains how insulin helps control the blood glucose level.
Insulin is absolutely vital for patients with type 1 diabetes; some people with type 2 diabetes can effectively control their blood glucose levels without it by taking medicine that either increases the body’s ability to make insulin or the effectiveness of insulin. Because diabetes is a progressive disease, it’s common for people with type 2 diabetes to need to add medicines over time to keep glucose levels in check.
Blood Glucose Monitoring
You have to watch your blood glucose levels throughout the day in order to know how much insulin you should be taking. At the very least, you should check your blood glucose level four times a day: before each meal and before bedtime.
Keeping tabs on your blood glucose helps you know if you need to readjust insulin or your meals in order to keep your level in a healthy range.
Another important part of blood glucose monitoring is the hemoglobin A1c test, which will give you an idea of your average blood glucose levels over the past three months. The daily monitoring helps you adjust on a moment-to-moment basis; the hemoglobin A1c test lets you know how well you’re doing overall.
For people with diabetic peripheral neuropathy—nerve damage caused by diabetes—taking good care of their feet is very important. The nerves most often affected by peripheral neuropathy are the ones leading to the feet, and this type of nerve damage can cause people to lose feeling in their feet.
This lack of sensation can cause extreme problems. For example, someone with diabetic peripheral neuropathy might develop a blister on the bottom of their foot. People without nerve damage would be able to feel that and take care of it properly.
However, if someone has lost sensation in the feet, they wouldn’t be able to feel the blister. It may eventually rub off and then become infected. Left untreated, that infection may spread to the bones, and then it may become necessary to amputate the foot in order to keep the infection from spreading.
It’s possible to avoid that scenario entirely—just by taking good care of your feet. For starters, make sure your doctor gives you a thorough foot examination at every appointment. In between appointments, you should check your own feet every day.
Here’s what you can do to take good care of your feet:
- Clean your feet every day.
- As you’re drying the feet (with a soft towel), check for redness, swelling, blisters, etc. Be sure to look between your toes. If you notice anything, report it to your doctor. If you have trouble bending over to see your feet, try using a mirror.
- Moisturize your feet with a good lotion. Be careful to not get any of the lotion in between your toes because it could actually cause an infection.
- Keep your toenails at a good length; this should help you avoid ingrown toenails.
- Wear shoes that fit well. It’s especially important that your toes are able to move and wiggle around, so look for shoes with a good-sized toe box.
- To avoid injuring your feet, always wear shoes or slippers. You don’t want to step on something—a small pebble, for instance—and injure your foot. You may not feel or notice that small injury, and it could grow into a bigger problem.
- Before you put on your shoes, make sure there isn’t anything in your shoe that could irritate your foot—a small pebble, for instance.
In taking good care of your feet, you’re being proactive in preventing severe complications from diabetic peripheral neuropathy.
