DIABETIC NEUROPATHY OVERVIEW
Neuropathy is the medical term for nerve damage. Neuropathy is a common complication of type 1 and type 2 diabetes; up to 26 percent of people with type 2 diabetes have evidence of nerve damage at the time that diabetes is diagnosed . A generalized type of neuropathy, known as polyneuropathy, is the most common type of diabetic neuropathy. Other types of neuropathy can also affect people with diabetes, but will not be discussed here.
Signs and symptoms of diabetic neuropathy include loss of sensation and/or burning pain in the feet. Early detection of diabetes and tight control of blood sugar levels may reduce the risk of developing diabetic neuropathy.
Treatments for diabetic neuropathy are available, and include several elements: control of blood glucose levels, prevention of injury, and control of painful symptoms.
DIABETIC NEUROPATHY RISK FACTORS
In people with type 1 or type 2 diabetes, the biggest risk factor for developing diabetic neuropathy is having high blood sugar levels over time.
Other factors can further increase the risk of developing diabetic neuropathy, including:
●Coronary artery disease
●Increased triglyceride levels
●Being overweight (a body mass index >24) (calculator 1 and calculator 2)
●High blood pressure
DIABETIC NEUROPATHY SYMPTOMS
The most common symptoms of diabetic neuropathy include pain, burning, tingling, or numbness in the toes or feet, and extreme sensitivity to light touch. The pain may be worst at rest and improve with activity, such as walking. Some people initially have intensely painful feet while others have few or no symptoms.
Diabetic neuropathy usually affects both sides of the body. Symptoms are usually noticed first in the toes. If the disease progresses, symptoms may gradually move up the legs; if the mid-calves are affected, symptoms may develop in the hands. Over time, the ability to sense pain may be lost, which greatly increases the risk of injury. (See "Clinical manifestations and diagnosis of diabetic polyneuropathy".)
Potential complications — As you lose the ability to sense pain or hot and cold, your risk of injuring your feet increases. Injuries that would normally cause pain (eg, stepping on a splinter, wearing shoes that create a blister, developing an ingrown toenail) do not necessarily cause pain if you have neuropathy. Unless you inspect your feet on a daily basis, a small injury has the potential to develop into a large ulcer. One of the most serious complications of foot ulcers is the need for amputation of a toe, or in extreme cases, the foot itself.
DIABETIC NEUROPATHY TESTS
Diabetic neuropathy is diagnosed based upon a medical history and physical examination of the feet. During an examination, there may be signs of nerve injury, including:
●Loss of the ability to sense vibration and movement in the toes or feet (eg, when the toe is moved up or down)
●Loss of the ability to sense pain, light touch and temperature in the toes or feet
●Loss or reduction of the Achilles tendon reflex
More extensive testing, including nerve conduction studies, nerve biopsy, or imaging tests (eg, x-ray or CT scan), is not usually needed to diagnose diabetic neuropathy.
DIABETIC NEUROPATHY TREATMENT
There are three main components of diabetic neuropathy treatment:
●Tight control of blood sugar levels
●Care for the feet to prevent complications
●Control of pain caused by neuropathy
Although there is no cure for diabetic neuropathy, use of these treatments can improve painful symptoms and prevent complications. (See "Treatment of diabetic neuropathy".)
Control blood sugar levels — One of the most important treatments for diabetic neuropathy is to control blood sugar levels. Symptoms of pain and burning may improve when blood glucose sugar improves. (See "Patient information: Self-blood glucose monitoring in diabetes mellitus (Beyond the Basics)".)
If blood sugar levels are not adequately controlled with the current treatment regimen, a different regimen may be recommended.
●For people with type 1 diabetes, this may mean taking more frequent insulin injections or using an insulin pump. (See "Patient information: Diabetes mellitus type 1: Insulin treatment (Beyond the Basics)".)
●For people with type 2 diabetes, this may mean taking an additional oral medication or starting insulin injections. (See "Patient information: Diabetes mellitus type 2: Treatment (Beyond the Basics)".)
Care for the feet — People with neuropathy do not always feel pain when there is a wound or injury on the foot. As a result, daily foot care is necessary to monitor for changes in the skin (such as cracks or wounds), which can increase the risk of infection. The American Diabetes Association recommends that people with diabetes have a comprehensive foot examination once per year, and a visual examination of the feet at each visit (usually every three to four months). Foot examinations are described in detail in a separate topic review. (See "Patient information: Foot care in diabetes mellitus (Beyond the Basics)".)
Avoid activities that can injure the feet — Some activities increase the risk of foot injury and are not recommended, including walking barefoot, using a heating pad or hot water bottle on the feet, and stepping into the bathtub before testing the temperature with the hand.
Use care when trimming the nails — Trim the toe nails along the shape of the toe (rounded, not straight across) and file the nails to remove any sharp edges (figure 1). Never cut (or allow a manicurist to cut) the cuticles. Do not pop blisters, try to free ingrown toenails, or otherwise break the skin on the feet. See a healthcare provider or podiatrist for even minor procedures.
Wash and check the feet daily — Use lukewarm water and mild soap to clean the feet. Gently pat feet dry and apply a moisturizing cream or lotion.
Check the entire surface of both feet for skin breaks, blisters, swelling, or redness, including between and underneath the toes where damage may be hidden. Use a mirror or ask a family member or caregiver to help if it is difficult to see the entire foot (figure 2).
Choose socks and shoes carefully — Select cotton socks that fit loosely, and change the socks every day. Wear shoes that are fit correctly and are not tight, and break new shoes in slowly to prevent blisters (figure 3). Ask about customized shoes if your feet are misshapen or have ulcers; specialized shoes can reduce the chances of developing foot ulcers in the future. Shoe inserts may also help cushion the step and decrease pressure on the soles of the feet.
Ask for foot exams — Screening for foot complications should be a routine part of most medical visits, but is sometimes overlooked. At each visit, the shoes and socks should be removed and the clinician should visually examine the feet. Do not hesitate to ask the healthcare provider for a complete foot check at least once a year, and more frequently if there are problems. (See "Evaluation of the diabetic foot".)
Control pain — Neuropathic pain can be difficult to control and can seriously affect your quality of life. Neuropathic pain is often worse at night, seriously disrupting sleep.
Fortunately, only a small percentage of people with diabetic neuropathy experience pain. Pain resolves without treatment in some people over a period of weeks to months, especially if the episode of pain developed after a sudden change in health (eg, an episode of diabetic ketoacidosis, a significant weight loss, or a significant change in blood glucose control).
There are several medications that are useful for the treatment of diabetic neuropathy and have been approved by the FDA, including duloxetine and pregabalin. Other medications are also useful, including tricyclic medications (eg, amitriptyline), gabapentin, tramadol, and alpha-lipoic acid.
Tricyclic antidepressants — There are several tricyclic antidepressants available for the treatment of chronic pain, including amitriptyline, nortriptyline, and desipramine. Clinical trials have shown than tricyclic antidepressant drugs are effective for patients with painful diabetic neuropathy. The dose of tricyclic antidepressants used to treat diabetic neuropathy is typically much lower than that used to treat depression.
These medications are usually taken at bedtime, starting with a low dose and gradually increasing over a period of several weeks. People with heart disease should not take amitriptyline or nortriptyline. Tricyclic medications can be taken with gabapentin and pregabalin, but should not be taken with duloxetine. Side effects can include dry mouth, sleepiness, dizziness, and constipation.
Duloxetine — Duloxetine is an antidepressant that is often effective in relieving pain caused by diabetic neuropathy. In short-term clinical trials, duloxetine was more effective than placebo. However, the long-term effectiveness and safety of duloxetine for diabetic neuropathy is uncertain . There are no trials comparing duloxetine with other drugs for the treatment of diabetic polyneuropathy.
Duloxetine is usually taken by mouth once per day on a full stomach, although in some cases it is taken twice per day. It should not be taken by people who take other antidepressant medications (see 'Tricyclic antidepressants' above). Side effects can include nausea, sleepiness, dizziness, decreased appetite, and constipation.
Gabapentin — Gabapentin is an anti-seizure medication. It is usually taken by mouth three times per day. Side effects can include dizziness and confusion. Gabapentin can be taken with a tricyclic antidepressants or duloxetine. In some cases, gabapentin can be taken at night to prevent pain during sleep.
Pregabalin — Pregabalin is an anti-seizure medication, similar to gabapentin. Pregabalin is taken by mouth, starting at bedtime at a low dose, and then gradually increasing to three times per day over a period of several weeks.
Side effects can include dizziness, sleepiness, confusion, swelling in the feet and ankles, and weight gain. It may be possible to become addicted to pregabalin, and changes in dosing should be monitored carefully. Pregabalin can be taken with duloxetine or TCAs, but not with gabapentin.
Anesthetic drugs — Lidocaine is an anesthetic drug that may be recommended if other treatments have not improved pain. It is applied to the painful area in a patch, which slowly releases the medication over time. Up to four patches may be applied for up to 18 hours per day.
Alpha-lipoic acid — Alpha-lipoic acid (ALA) is an antioxidant medication. Several short-term trials showed that it was helpful in relieving pain caused by diabetic neuropathy. Thus, ALA may be recommended to people with diabetic neuropathy who do not improve with or who cannot tolerate other treatments. However, longer-term studies are still needed to confirm its safety and effectiveness. In the United States, ALA is available without a prescription as a dietary supplement. It is usually taken by mouth once per day.
Narcotics (opioids) — Tramadol is a pain medication that can be taken for breakthrough pain; in severe cases, it can be taken every six hours (four times per day). It can cause sedation, dizziness and confusion. It can be taken with pregabalin, duloxetine, gabapentin, and TCAs.
It is important to note that the long-term use of narcotic medications for non-cancer pain is associated with a number of problems, including the potential for abuse, addiction, and fatal overdose, particularly for patients treated with higher dose regimens. Because of these issues, some clinicians have stopped using narcotics altogether for the treatment of painful diabetic neuropathy.
WHERE TO GET MORE INFORMATION
Your healthcare provider is the best source of information for questions and concerns related to your medical problem.
This article will be updated as needed on our web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.
Patient level information — UpToDate offers two types of patient education materials.
The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.
Patient information: Type 2 diabetes (The Basics)
Patient information: Nerve damage caused by diabetes (The Basics)
Patient information: The ABCs of diabetes (The Basics)
Patient information: Neuropathic pain (The Basics)
Patient information: Diabetes and infections (The Basics)
Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.
Patient information: Foot care in diabetes mellitus (Beyond the Basics)
Patient information: Self-blood glucose monitoring in diabetes mellitus (Beyond the Basics)
Patient information: Diabetes mellitus type 1: Insulin treatment (Beyond the Basics)
Patient information: Diabetes mellitus type 2: Treatment (Beyond the Basics)
Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.
Clinical manifestations and diagnosis of diabetic polyneuropathy
Diabetic autonomic neuropathy
Diabetic autonomic neuropathy of the gastrointestinal tract
Epidemiology and classification of diabetic neuropathy
Evaluation of the diabetic foot
Pathogenesis and prevention of diabetic polyneuropathy
Treatment of diabetic neuropathy
The following organizations also provide reliable health information.
●National Library of Medicine (www.nlm.nih.gov/medlineplus/ency/article/000693.htm, available in Spanish)
●National Institute of Diabetes and Digestive and Kidney Diseases (http://diabetes.niddk.nih.gov/dm/pubs/neuropathies/)
●American Diabetes Association (www.diabetes.org) (800)-DIABETES (800-342-2383)
●The Neuropathy Association (www.neuropathy.org)