High blood sugar can lead to nerve damage in feet and other areas of the body. Know the signs and how to take steps to prevent this diabetes complication.
Diabetic neuropathy is a type of nerve damage that can occur if you have diabetes. High blood sugar (glucose) can injure nerves throughout your body. Diabetic neuropathy most often damages nerves in your legs and feet.
Depending on the affected nerves, diabetic neuropathy symptoms can range from pain and numbness in your legs and feet to problems with your digestive system, urinary tract, blood vessels and heart. Some people have mild symptoms. But for others, diabetic neuropathy can be quite painful and disabling.
Diabetic neuropathy is a serious diabetes complication that may affect as many as 50% of people with diabetes. But you can often prevent diabetic neuropathy or slow its progress with consistent blood sugar management and a healthy lifestyle.
There are four main types of diabetic neuropathy. You can have one type or more than one type of neuropathy.
Your symptoms will depend on the type you have and which nerves are affected. Usually, symptoms develop gradually. You may not notice anything is wrong until considerable nerve damage has occurred.
This type of neuropathy may also be called distal symmetric peripheral neuropathy. It's the most common type of diabetic neuropathy. It affects the feet and legs first, followed by the hands and arms. Signs and symptoms of peripheral neuropathy are often worse at night, and may include:
- Numbness or reduced ability to feel pain or temperature changes
- Tingling or burning sensation
- Sharp pains or cramps
- Increased sensitivity to touch — for some people, even a bedsheet's weight can be painful
- Serious foot problems, such as ulcers, infections, and bone and joint pain
The autonomic nervous system controls your heart, bladder, stomach, intestines, sex organs and eyes. Diabetes can affect nerves in any of these areas, possibly causing:
- A lack of awareness that blood sugar levels are low (hypoglycemia unawareness)
- Bladder or bowel problems
- Slow stomach emptying (gastroparesis), causing nausea, vomiting and loss of appetite
- Changes in the way your eyes adjust from light to dark
- Decreased sexual response
Proximal neuropathy (diabetic polyradiculopathy)
This type of neuropathy — also called diabetic amyotrophy — often affects nerves in the thighs, hips, buttocks or legs. It can also affect the abdominal and chest area. Symptoms are usually on one side of the body, but may spread to the other side. You may have:
- Severe pain in a hip and thigh or buttock
- Eventual weak and shrinking thigh muscles
- Difficulty rising from a sitting position
- Severe stomach pain
Mononeuropathy (focal neuropathy)
There are two types of mononeuropathy — cranial and peripheral. Mononeuropathy refers to damage to a specific nerve. Mononeuropathy may also lead to:
- Difficulty focusing or double vision
- Aching behind one eye
- Paralysis on one side of your face (Bell's palsy)
- Numbness or tingling in your hand or fingers, except your pinkie (little finger)
- Weakness in your hand that may cause you to drop things
When to see a doctor
Call your doctor for an appointment if you have:
- A cut or sore on your foot that is infected or won't heal
- Burning, tingling, weakness or pain in your hands or feet that interferes with daily activities or sleep
- Changes in digestion, urination or sexual function
- Dizziness and fainting
The American Diabetes Association recommends that screening for diabetic neuropathy begin immediately after someone is diagnosed with type 2 diabetes, and five years after diagnosis for someone with type 1 diabetes. After that, screening is recommended annually.
The exact cause of each type of neuropathy is unknown. Researchers think that over time, uncontrolled high blood sugar damages nerves and interferes with their ability to send signals, leading to diabetic neuropathy. High blood sugar also weakens the walls of the small blood vessels (capillaries) that supply the nerves with oxygen and nutrients.
Anyone who has diabetes can develop neuropathy. But these risk factors make you more likely to get nerve damage:
- Poor blood sugar control. Uncontrolled blood sugar puts you at risk of every diabetes complication, including nerve damage.
- Diabetes history. Your risk of diabetic neuropathy increases the longer you have diabetes, especially if your blood sugar isn't well controlled.
- Kidney disease. Diabetes can damage the kidneys. Kidney damage sends toxins into the blood, which can lead to nerve damage.
- Being overweight. Having a body mass index (BMI) of 25 or more may increase your risk of diabetic neuropathy.
- Smoking. Smoking narrows and hardens your arteries, reducing blood flow to your legs and feet. This makes it more difficult for wounds to heal and damages the peripheral nerves.
Diabetic neuropathy can cause a number of serious complications, including:
- Hypoglycemia unawareness. Blood sugar levels below 70 milligrams per deciliter (mg/dL) normally cause shakiness, sweating and a fast heartbeat. But if you have autonomic neuropathy, you may not notice these warning signs.
- Loss of a toe, foot or leg. Nerve damage can make you lose feeling in your feet, so even minor cuts can turn into sores or ulcers without your realizing it. In severe cases, an infection can spread to the bone or lead to tissue death. Removal (amputation) of a toe, foot or even the lower leg may be necessary.
- Urinary tract infections and urinary incontinence. If the nerves that control your bladder are damaged, you may be unable to fully empty your bladder. Bacteria can build up in the bladder and kidneys, causing urinary tract infections. Nerve damage can also affect your ability to feel when you need to urinate or to control the muscles that release urine, leading to leakage (incontinence).
- Sharp drops in blood pressure. Damage to the nerves that control blood flow can affect your body's ability to adjust blood pressure. This can cause a sharp drop in pressure when you stand after sitting, which may lead to dizziness and fainting.
- Digestive problems. If nerve damage strikes your digestive tract, you can have constipation or diarrhea, or both. Diabetes-related nerve damage can lead to gastroparesis, a condition in which the stomach empties too slowly or not at all, which causes bloating and indigestion.
- Sexual dysfunction. Autonomic neuropathy often damages the nerves that affect the sex organs. Men may experience erectile dysfunction. Women may have difficulty with lubrication and arousal.
- Increased or decreased sweating. Nerve damage can disrupt how your sweat glands work and make it difficult for your body to control its temperature properly.
You can prevent or delay diabetic neuropathy and its complications by closely managing your blood sugar and taking good care of your feet.
Blood sugar management
The American Diabetes Association recommends that people with diabetes have an A1C test at least twice a year. This test estimates your average blood sugar level for the past two to three months.
A1C goals may need to be individualized, but for many adults, the American Diabetes Association recommends an A1C of less than 7%. If your blood sugar levels are higher than your goal, you may need changes in your daily management, such as adding or adjusting your medications or changing your diet.
Foot problems, including sores that don't heal, ulcers and even amputation, are common complications of diabetic neuropathy. But you can prevent many of these problems by having a thorough foot exam at least once a year, having your doctor check your feet at each office visit and taking good care of your feet at home.
Follow your doctor's recommendations for good foot care. To protect the health of your feet:
- Check your feet every day. Look for blisters, cuts, bruises, cracked and peeling skin, redness, and swelling. Use a mirror or ask a friend or family member to help examine parts of your feet that are hard to see.
- Keep your feet clean and dry. Wash your feet every day with lukewarm water and mild soap. Avoid soaking your feet. Dry your feet and between your toes carefully.
- Moisturize your feet. This helps prevent cracking. But don't get lotion between your toes, because it might encourage fungal growth.
- Trim your toenails carefully. Cut your toenails straight across. File the edges carefully to avoid sharp edges.
- Wear clean, dry socks. Look for socks made of cotton or moisture-wicking fibers that don't have tight bands or thick seams.
- Wear cushioned shoes that fit well. Always wear shoes or slippers to protect your feet. Make sure your shoes fit properly and allow your toes to move. A foot doctor can teach you how to buy properly fitted shoes and to prevent problems such as corns and calluses. If you qualify for Medicare, your plan may cover the cost of at least one pair of shoes each year.
A doctor can usually diagnose diabetic neuropathy by performing a physical exam and carefully reviewing your symptoms and medical history.
Your doctor will check your:
- Overall muscle strength and tone
- Tendon reflexes
- Sensitivity to touch and vibration
Along with the physical exam, your doctor may perform or order specific tests to help diagnose diabetic neuropathy, such as:
- Filament test. Your doctor will brush a soft nylon fiber (monofilament) over areas of your skin to test your sensitivity to touch.
- Sensory testing. This noninvasive test is used to tell how your nerves respond to vibration and changes in temperature.
- Nerve conduction testing. This test measures how quickly the nerves in your arms and legs conduct electrical signals. It's often used to diagnose carpal tunnel syndrome.
- Muscle response testing. Called electromyography, this test is often done with nerve conduction studies. It measures electrical discharges produced in your muscles.
- Autonomic testing. Special tests may be done to determine how your blood pressure changes while you are in different positions, and whether you sweat normally.
Diabetic neuropathy has no known cure. The goals of treatment are to:
- Slow progression of the disease
- Relieve pain
- Manage complications and restore function
Slowing progression of the disease
Consistently keeping your blood sugar within your target range is the key to preventing or delaying nerve damage. Good blood sugar management may even improve some of your current symptoms. Your doctor will figure out the best target range for you based on factors including your age, how long you've had diabetes and your overall health.
Blood sugar levels may need to be individualized. But, in general, the American Diabetes Association recommends the following target blood sugar levels for most people with diabetes:
- Between 80 and 130 mg/dL, which is 4.4 and 7.2 millimoles per liter (mmol/L) before meals
- Less than 180 mg/dL (10.0 mmol/L) two hours after meals
Mayo Clinic encourages slightly lower blood sugar levels for most younger people with diabetes, and slightly higher levels for older people who may be more at risk of low blood sugar complications. Mayo Clinic generally recommends the following target blood sugar levels before meals:
- Between 80 and 120 mg/dL (4.4 and 6.7 mmol/L) for people age 59 and younger who have no other medical conditions
- Between 100 and 140 mg/dL (5.6 and 7.8 mmol/L) for people age 60 and older, or for those who have other medical conditions, including heart, lung or kidney disease
Other important ways to help slow or prevent neuropathy from getting worse include keeping your blood pressure under control, maintaining a healthy weight and getting regular physical activity.
Many prescription medications are available for diabetes-related nerve pain, but they don't work for everyone. When considering any medication, talk to your doctor about the benefits and possible side effects to find what might work best for you.
Pain-relieving prescription treatments may include:
- Anti-seizure drugs. Some medications used to treat seizure disorders (epilepsy) are also used to ease nerve pain. The American Diabetes Association recommends starting with pregabalin (Lyrica). Gabapentin (Gralise, Neurontin) also is an option. Side effects may include drowsiness, dizziness and swelling.
Antidepressants. Some antidepressants ease nerve pain, even if you aren't depressed. Tricyclic antidepressants may help with mild to moderate nerve pain. Drugs in this class include amitriptyline, desipramine (Norpramin) and imipramine (Tofranil). Side effects can be bothersome and include dry mouth and drowsiness.
Serotonin and norepinephrine reuptake inhibitors (SNRIs) are another type of antidepressant that may help with nerve pain and have fewer side effects. The American Diabetes Association recommends duloxetine (Cymbalta) as a first treatment. Another that may be used is venlafaxine (Effexor XR). Possible side effects include nausea, sleepiness, dizziness, decreased appetite and constipation.
Sometimes, an antidepressant may be combined with an anti-seizure drug. These drugs can also be used with pain-relieving medication, such as an over-the-counter medication including acetaminophen (Tylenol, others) or ibuprofen (Advil, Motrin IB, others) or a skin patch with lidocaine (a numbing substance).
Managing complications and restoring function
To manage complications, you may need care from different specialists, such as a doctor that treats urinary tract problems (urologist) and a heart doctor (cardiologist), who can help prevent or treat complications.
The treatment you'll need depends on the neuropathy-related complication you have:
- Urinary tract problems. Some drugs affect bladder function, so your doctor may recommend stopping or changing medications. A strict urination schedule or urinating every few hours (timed urination) while applying gentle pressure to the bladder area (below your bellybutton) can help some bladder problems. Other methods, including self-catheterization, may be needed to remove urine from a nerve-damaged bladder.
- Digestive problems. To relieve mild signs and symptoms of gastroparesis — indigestion, belching, nausea or vomiting — doctors suggest eating smaller, more-frequent meals. Diet changes and medications may help relieve gastroparesis, diarrhea, constipation and nausea.
- Low blood pressure on standing (orthostatic hypotension). Treatment starts with simple lifestyle changes, such as avoiding alcohol, drinking plenty of water, and changing positions such as sitting or standing slowly. Sleeping with the head of the bed raised 6 to 10 inches helps prevent swings in blood pressure. Your doctor may also recommend compression support for your abdomen (abdominal binder). Several medications, either alone or together, may be used to treat orthostatic hypotension.
- Sexual dysfunction. Medications taken by mouth or injection may improve sexual function in some men, but they aren't safe and effective for everyone. Mechanical vacuum devices may increase blood flow to the penis. Women may find relief with vaginal lubricants.
These measures can help you feel better overall and reduce your risk of diabetic neuropathy:
- Keep your blood pressure under control. If you have high blood pressure and diabetes, you have an even greater risk of complications. Try to keep your blood pressure in the range your doctor recommends, and be sure to have it checked at every office visit.
- Make healthy food choices. Eat a balanced diet that includes a variety of healthy foods — especially vegetables, fruits and whole grains. Limit portion sizes to help achieve or maintain a healthy weight.
Be active every day. Exercise helps lower blood sugar, improves blood flow and keeps your heart healthy. The American Diabetes Association recommends 150 minutes of moderate-intensity exercise a week for most adults with diabetes. It's also a good idea to take a break from sitting every 30 minutes to get a few quick bursts of activity.
Talk with your doctor or physical therapist before you start exercising. If you have decreased feeling in your legs, some types of exercise, such as walking, may be safer than others. If you have a foot injury or sore, stick with exercise that doesn't require putting weight on your injured foot.
- Stop smoking. Using tobacco in any form makes you more likely to develop poor circulation in your feet. If you use tobacco, talk to your doctor about finding ways to quit.
There are also many alternative therapies that may help with pain relief on their own or in combination with medications. But check with your doctor before using any alternative therapy or dietary supplement to make sure to avoid any potential interactions. For diabetic neuropathy, you may want to try:
- Capsaicin. Capsaicin cream, applied to the skin, can reduce pain sensations in some people. Side effects may include a burning feeling and skin irritation.
- Alpha-lipoic acid. This powerful antioxidant is found in some foods and may help relieve nerve pain symptoms in some people.
- Acetyl-L-carnitine. This nutrient is naturally made in the body and available as a supplement. It may ease nerve pain in some people.
- Transcutaneous electrical nerve stimulation (TENS). Your doctor may prescribe this therapy, which may help prevent pain signals from reaching your brain. TENS delivers tiny electrical impulses to specific nerve pathways through small electrodes placed on your skin. Although safe and painless, TENS doesn't work for everyone or for all types of pain.
- Acupuncture. Acupuncture may help relieve the pain of neuropathy, and generally doesn't have any side effects. Keep in mind that you may not get immediate relief with acupuncture and will likely require more than one session.
Living with diabetic neuropathy can be difficult and frustrating. If you find yourself feeling depressed, it may help to talk to a counselor or therapist.
Support groups also can offer encouragement and advice about living with diabetic neuropathy. Ask your doctor if there are any in your area, or for a referral to a therapist. The American Diabetes Association offers online support through its website.
If you don't already see an endocrinologist, you'll likely be referred to one if you start showing signs of diabetes complications. An endocrinologist is a doctor who specializes in treating metabolic disorders, such as diabetes. You may also be referred to a neurologist, which is a doctor who specializes in treating nervous system problems.
To prepare for your appointment, you may want to:
- Be aware of any pre-appointment restrictions. When you make the appointment, ask if there's anything you need to do in advance, such as restrict your diet.
- Write down any symptoms you're having, including any that may seem unrelated to the reason for the appointment.
- Write down key personal information, including any major stresses or recent life changes.
- Make a list of all medications, vitamins and supplements you're taking.
- Write down your recent blood sugar levels, if you check them at home.
- Ask a family member or friend to come with you. It can be difficult to remember everything your doctor tells you during an appointment. Someone who accompanies you may remember something that you missed or forgot.
You may also want to write down questions to ask your doctor. For diabetic neuropathy, some basic questions include:
- Is diabetic neuropathy the most likely cause of my symptoms?
- Do I need tests to confirm the cause of my symptoms? How do I prepare for these tests?
- Is this condition temporary or long lasting?
- If I manage my blood sugar, will these symptoms improve or go away?
- Are there treatments available, and which do you recommend?
- What types of side effects can I expect from treatment?
- I have other health conditions. How can I best manage them together?
- Are there brochures or other printed material I can take with me? What websites do you recommend?
- Do I need to see other doctors, a certified diabetes educator or a dietitian?
What to expect from your doctor
Your doctor is likely to ask you a number of questions, such as:
- How effective is your diabetes management?
- When did you start having symptoms?
- Do you always have symptoms or do they come and go?
- How severe are your symptoms?
- Does anything seem to improve your symptoms?
- What, if anything, appears to make your symptoms worse?
- What's challenging about managing your diabetes?
- What might help you manage your diabetes better?
October 28th, 2021