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Diabetes causes damage to the nerves — this is called diabetic neuropathy.
For most people, diabetic neuropathy means tingling, burning, numbness, and pain in the extremities, especially the feet. This condition, called peripheral neuropathy, may affect as many as half of people with diabetes, though estimates of its prevalence range widely.
But it’s not just the feet, legs, and hands. The nervous system touches every part of the body, and neuropathy can affect the digestive system, the heart, the eyes, the bladder, the sweat glands, and sexual organs. Neuropathy can eventually lead to very severe outcomes, such as amputation.
There are several risk factors, but diabetic neuropathy is primarily caused by high blood sugar. The risk increases with age and the duration of diabetes.
Causes of Neuropathy
Diabetic neuropathy is ultimately caused by “longstanding hyperglycemia,” according to a 2011 review. Excess sugar in the bloodstream leads to inflammation and oxidative stress, causing dysfunction and damage to the nerves.
Additional risk factors can accelerate the progression and development of neuropathy, including:
- Hypertension (high blood sugar)
- High cholesterol
- Smoking
- Insulin resistance
Glucose control “effectively halts the progression of diabetic neuropathy” in people with type 1 diabetes, though the effects are more modest in those with type 2, according to a 2013 article.
Types of Neuropathy
Peripheral Neuropathy
The most common type affecting people with diabetes, peripheral neuropathy can be felt as pain, tingling, burning, prickling, numbness, and complete loss of feeling in the extremities. Feet will usually be the first place symptoms arise and symptoms will tend to be worse at night. These symptoms can range from barely noticeable discomfort to excruciating and debilitating pain. Peripheral neuropathy is both under-assessed and undertreated.
When areas become numb on the feet or extremities, you may not notice blisters or small injuries, which then can easily become infected. If an infection isn’t noticed due to loss of feeling, it can spread; in extreme cases, infections can result in amputation. This is why for people with neuropathy in their feet, it is very important to perform regular foot checks for injuries and blisters and to never neglect any signs of infection. Taking care of infections in time will help lower the risk of amputation.
The discomfort and pain from peripheral neuropathy can be very difficult to address. Patients that do find some relief often use a combination of prescription medication, over-the-counter treatments, and non-medicinal techniques such as massage or foot elevation. Good blood sugar management is the only therapy that addresses the root cause.
We have an entire article on solving the puzzle of painful peripheral neuropathy: How To Treat Pain from Diabetic Neuropathy.
Autonomic Neuropathy
Autonomic neuropathy affects the nerves that control the internal organs. As explained by the National Institutes of Health, autonomic neuropathy can cause dysfunction in many unrelated bodily processes:
- Unpredictable heart rate and blood pressure
In a healthy person, the body has an exquisite ability to adjust heart rate and blood pressure based on many different variables, such as physical position and activity levels. Autonomic neuropathy can dull this ability to make quick and precise changes, which can cause your blood pressure or pulse to behave inappropriately. This can have many uncomfortable effects, for example, leaving you light-headed, or with a racing heartbeat while at rest.
- Gastrointestinal distress
If the nerves serving your digestive system don’t work properly, your organs, including the esophagus, stomach, intestines and bowels, do not respond well to the cues that help us consume, digest, and dispose of our food. This can lead to many nasty side effects, including nausea, constipation, diarrhea, and vomiting.
Gastroparesis is a complication of the stomach that deserves special mention. In this condition, the stomach empties too slowly, which can lead to regular feelings of nausea, vomiting, bloating, and loss of appetite. Gastroparesis can also make it very difficult to manage blood sugars, because it becomes far more difficult to predict when consumed carbohydrates will actually reach the bloodstream.
The pupils of the eyes can be affected by nerve damage, too. This may cause them to inadequately respond to light changes. This may cause a person to struggle to see in the dark and may make night driving more challenging.
Damage to the nerves that control sweat glands can cause them to function improperly. A person may sweat very much at inappropriate times, such as at night or while eating. Other sweat glands may never work at all.
Both men and women with diabetes can experience sexual dysfunction due to autonomic neuropathies. This may take the form of erectile dysfunction in men, and vaginal dryness in women. And adults of any type can experience a loss of sex drive due to dysfunctional nerve signaling.
If the bladder’s nerves are not functioning problem, it will have a reduced ability to respond properly to the cues that usually control urination. As a result, you may not perceive the need to urinate until the bladder is already overfull. If the muscles needed for urination control or affected, you may leak urine.
Focal Neuropathy
Focal neuropathies are less common than peripheral and autonomic neuropathies. These conditions affect only one nerve, often affecting the fingers or toes. Your digits may feel weak, painful, or numb.
A very common focal neuropathy in diabetes is carpal tunnel syndrome, in which a nerve in the wrist is pinched, leading to hand and finger pain.
Diabetic Amyotrophy (Hip Pain and Weakness)
Diabetic amyotrophy — also known as proximal neuropathy and diabetic lumbosacral radiculoplexus neuropathy (DLRPN) — is a rare complication of diabetes that impacts the nerves in the hips and surrounding areas, such as the thighs and buttocks. It can result in weakness, muscle loss, and debilitating pain, making it difficult or impossible to walk.
The condition is typically active for two years or less, but the road to recovery can be very long. Many people will never completely recover their mobility.
How to Lower Risk for Diabetic Neuropathy
The US Centers for Disease Control and Prevention advises people with diabetes to prioritize blood sugar control and to otherwise pursue a metabolically health lifestyle:
The best way to reduce the risk of nerve damage is to control blood glucose levels as well as possible. High blood sugar is the central root cause of diabetic neuropathy, and removing it can have a dramatic positive effect.
How is Neuropathy Treated?
The most important element of any treatment of diabetic neuropathy is glycemic and metabolic control. Good diabetes management is the only way to remove the root cause of diabetic nerve damage.
Otherwise, treatment of the symptoms of neuropathy will vary based on the type of nerve damage involved.
- Peripheral neuropathy can be managed both with medicine (including gabapentin, pain killers, and tricyclic antidepressants) and with non-medicinal measures (including massage, elevation, and healthy sleep habits).
- It may be possible to address gastrointestinal distress, including gastroparesis, with a specialized diet.
- Urinary issues may be alleviated with medicines or different drinking habits.
- Sexual dysfunction can potentially alleviated with medications such as Viagra.
- Some issues, including carpal tunnel syndrome and amyotrophy, may require physical therapy for a full recovery.
Can Nerve Damage be Reversed?
The Cleveland Clinic says: “maybe.”
There are many anecdotal stories in the diabetes community attesting that blood sugar improvements actually “reversed” neuropathy. However, to our knowledge, there is little scientific evidence of the phenomenon. It is apparent that good glucose control can, at the very least, halt the progression of peripheral neuropathy, but most diabetes authorities claim that diabetic neuropathy cannot be reversed.
The bottom line? Whether or not it’s possible to reverse diabetic neuropathy, good glucose and metabolic control is the best possible way to ensure that your symptoms do not get worse.
If you are having issues with any of the parts of the body discussed in this article, please share your concerns with a doctor. Make sure to see a healthcare provider each year to talk about your symptoms. Earlier treatment usually leads to improved outcomes.