Diabetic neuropathy is nerve damage caused by the chronically high levels of glucose (sugar) in the blood associated with diabetes. There are several different types of neuropathy, with peripheral neuropathy and autonomic neuropathy being the most common.
Depending on the type, symptoms can include pain or numbness in the hands, feet, or legs; problems with blood pressure; bladder and digestive disorders; and other issues. It's estimated that up to 50% of adults with diabetes eventually develop peripheral neuropathy, which can lead to serious complications including the need for digit or limb amputation.
Types of Diabetic Neuropathy
There are several types of neuropathy that may develop in relation to diabetes. Some people experience just one of these types, while others may have more than one.
- Peripheral neuropathy is the most common type of neuropathy. It affects the extremities, such as toes, feet, fingers, and hands, but may also involve the legs and arms.
- Autonomic neuropathy affects the nerves that control body systems and are responsible for everyday body functioning, such as blood pressure, sweating, and digestion.
- Proximal neuropathy is a rare form of nerve damage affecting the hip, thigh, or buttocks. It usually affects only one side of the body.
- Focal neuropathy affects a single nerve, such as in the wrist or the back, and may also affect the nerve that controls the eye muscles. It is less common than peripheral or autonomic neuropathy.
Other less common forms of neuropathy include:
- Femoral neuropathy
- Charcot's joint or neuropathic arthropathy
- Compression mononeuropathy
- Cranial neuropathy
- Thoracic or lumbar radiculopathy
- Unilateral foot drop
- Cardiovascular autonomic neuropathy
Diabetic Neuropathy Symptoms
The symptoms of diabetic neuropathy depend on the type of neuropathy a person has and which specific nerves are damaged.
Symptoms can range from mild to disabling. And while they most often worsen gradually, it's possible for severe symptoms to appear suddenly.
Peripheral neuropathy usually affects both sides of the body. Symptoms can include:
- Burning pain in hands and feet
- Numbness and tingling
- Loss of sensation of pain or temperature
- Sensitivity to touch
- Difficulty walking due to coordination issues
- Muscle weakness
- Sores on the feet due to an inability to notice an injury
Autonomic neuropathy symptoms can vary widely, depending on which organs are involved. People may experience:
- Rapid heart rate
- Dizziness or lightheadedness when changing positions
- Bloating and nausea
- Diarrhea or constipation
- Bladder issues
- Vaginal dryness
- Erectile dysfunction
- Excessive or decreased sweating
- Inability to sense low blood sugar signs
- Double vision
Proximal neuropathy can cause pain in a hip, buttock, or thigh, and weakness and loss of muscle in the corresponding leg. The weakness may make it difficult to stand up.
Focal neuropathy, by definition, affects one nerve. If a nerve in the arm or hand is damaged, it can lead to pain, numbness, or weakness of that hand. If a nerve in the face is affected, Bell's palsy might result. Damage to an eye nerve might lead to double vision.
Consistently elevated blood sugar levels can cause diabetic neuropathy.
Over time, uncontrolled glucose levels interfere with nerve signaling and functioning. This may lead to weakening blood capillary walls, which could starve nerves of oxygen and nutrients.
Uncontrolled glucose levels interfere with nerve signaling and functioning.
Additionally, high blood cholesterol levels, high blood pressure, and low levels of vitamin B12 can also lead to neuropathy.
The diabetes medication metformin has a side effect that reduces B12 levels in the body. If you take metformin, talk to your healthcare provider about potentially supplementing with vitamin B12 to counteract this effect.
The risk of neuropathy increases with advanced age, being overweight, and duration of diabetes, with the highest rates among those who have had diabetes for more than 25 years.
The risk also significantly increases with smoking and alcohol abuse, which can narrow and weaken the arteries and reduce blood flow to your extremities.
Neuropathy may sometimes also be caused by kidney disease, a mechanical injury such as carpal tunnel syndrome, genetic factors, certain toxins, or widespread inflammation, which could trigger an autoimmune response that attacks the nerves.
A diagnosis of diabetic neuropathy can usually be made based on a physical exam, an assessment of your symptoms and your medical history, and specific tests to rule out other conditions when needed.
All people with diabetes should have their feet examined at least once a year to check for signs of peripheral neuropathy. Your healthcare provider will check the blood flow in your feet, the health of the skin, and your sensitivity to touch, temperature, and vibration.
An exam for peripheral neuropathy might also include testing your balance, reflexes, and your walking gait. A nerve conduction study or electromyelography might be done to test how well the nerves are working.
For autonomic neuropathy, specific tests would depend on the symptoms you're experiencing. Your provider may check how your heart rate and blood pressure changes with movement. Tests can assess bladder and digestive functions, or sweating.
It might also be necessary to rule out other possible causes of neuropathy symptoms. This could include imaging tests such as X-rays or ultrasound, blood tests to check thyroid function and B12 levels, an eye exam, or more specific tests.
The best way to treat diabetic neuropathy is to manage pain and work to prevent progression of the condition.
Because the root cause of diabetic neuropathy is diabetes, it's important to keep your blood sugar in your target range.
Consult with your healthcare provider to implement a therapeutic lifestyle plan incorporating medication and supplements, nutrition, and exercise, and keeping up with proper foot care.
Regularly test your blood glucose levels with a glucometer to establish a baseline level of your condition and to inform your daily decisions.
If your glycemic control is stable, you should get a hemoglobin A1C lab test or another evaluation at least twice a year to provide a glimpse of your average blood sugar control over the past few months, according to the American Diabetes Association (ADA).
If you do not have adequate control of your blood glucose levels, you should have an A1C test at least four times a year. The same is true if you've recently changed your treatment strategy.
What Is the A1C Test?
Not everyone with neuropathy will experience nerve pain. For those who do, over-the-counter pain relievers like Tylenol (acetaminophen) or nonsteroidal anti-inflammatory drugs (NSAIDs) like Motrin or Aleve (ibuprofen) may be helpful.
Healthcare providers are also now recommending very low-dose tricyclic antidepressants (TCAs) such as amitryptiline for chronic pain, or anti-epilepsy drugs (AEDs) such as Neurontin (gabapentin) or Lyrica (pregabalin), which work by decreasing the frequency of nerve pain signals sent to the brain. Other treatments include topical therapies such as Qutenza (capsaicin).
In some cases, neuropathy pain may not be responsive to pain medication. This can lead to muscle weakening or more serious disability. Reach out to your healthcare team if you cannot ease your discomfort and ask about an adjustment to your care plan.
In diabetic neuropathy, the feet are at higher risk because they are not easy to see. A foreign object such as a tack can get stuck in the bottom of the foot or irritation can develop into an open wound or ulcer and go unnoticed because of lost sensation.
People with diabetes need to take special care of their feet, and regularly inspect them for problems. Poor circulation is a common problem and could lead to slower healing, ulcers, infections or tissue death (gangrene), which may require amputation.
Over half of all amputations each year are due to diabetes and diabetes-related complications. Most are lower-extremity amputations, such asfoot amputation. Diligent foot care, however, can prevent these operations from becoming necessary.
Take care to:
- Inspect, wash, and thoroughly dry your feet daily.
- Always wear well-fitting shoes and clean, dry socks; avoid walking barefoot.
- Trim toenails straight across and file the corners with an emery board, or have them trimmed by a podiatrist.
- Don't use foot products, tools, or chemicals, such as scrapers, scissors, files, or wart removal treatments, as these may cause injury.
- Do not smoke. Smoking restricts blood flow to the feet.
- Let your healthcare provider know if you have a foot injury that is not healing normally within a couple of days, or if you discover an injury of unknown origin and duration.
A Word From Verywell
If you have type 1 or type 2 diabetes, it's important to be on the lookout for signs of diabetic neuropathy. Losing feeling or noticing tingling in any part of the body is a telltale signal that something may be wrong.
Actively working to keep your glucose levels under control is the best way to manage and prevent neuropathy from progressing.