Painful Diabetic Neuropathy
By Lori Montgomery, MD, CCFP
Diabetic neuropathies (say: die-uh-BET-ik noo-ROP-e-thees) are a group of disorders that can cause pain, along with numbness, weakness, or odd sensations. Up to 70% (7 out of 10) of people who have diabetes (both Type 1 and Type 2) have some form of neuropathy. This can involve the hands, feet, arms, and legs. It can sometimes also affect the digestive tract, heart, or sex organs.
Signs and symptoms
Some patients who have diabetic neuropathy have no symptoms at all. Others may have:
- numbness and tingling in the hands and feet
- pain in the hands and feet, especially burning, electric shock-like pain
- extreme sensitivity of the skin, similar to a bad sunburn
- weakness in the muscles of the hands or feet
- erectile dysfunction (problems having or keeping an erection) in men, or vaginal dryness in women
- difficulty urinating (peeing)
- constipation or diarrhea
- feeling dizzy or lightheaded when standing quickly
Because there are so many possible symptoms of diabetic neuropathy in different people, researchers think there are likely a number of ways that diabetes causes nerve damage. But in general, high levels of blood sugar are toxic to nerves and impair their ability to heal and recover from injury. There is also damage to blood vessels in diabetes. This means that nerves can not get the oxygen they need to survive. If you smoke cigarettes or drink beyond the usual amounts of alcohol, this can also be damaging to small nerves in the hands and feet, and can make diabetic peripheral neuropathy worse.
Some people with diabetes do not develop neuropathy. This may mean that part of the cause is genetic as well. This may make some people more prone to nerve injury than others.
There are a number of tests that can help to diagnose diabetic neuropathy and guide treatment.
The simplest test is a small filament, which your doctor can use in the office to test your sensation. The device applies a consistent amount of pressure so your doctor can compare how sensitive your skin is to that of a person without neuropathy. Often this is the only test that needs to be done.
Quantitative sensory testing (QST)
Quantitative sensory testing (QST) can be used to make note of changes in your condition over time. This test checks your sensitivity to light touch, pinprick, pressure, vibration, and temperature. It is very rarely needed, but is helpful in research studies to look at disease progression.
Nerve conduction studies (NCS) or electromyography (EMG)
Nerve conduction studies (NCS) or electromyography (EMG) check how well an electrical signal is being passed through a nerve or how well the muscles respond to the nerve signal. Most often, these tests are not needed but may help to rule out other causes of nerve damage, if needed.
How much your blood pressure and heart rate change over time can suggest problems with your autonomic nerves. These nerves control those non-voluntary functions.
Control of blood sugar
The most important way to prevent and treat diabetic neuropathy is good control of blood sugar. This can prevent further damage. When sugars are controlled for the first time, some patients find that the pain is worse for a little while, then improves.
There are a number of medicines that are used to control nerve pain. Some patients may benefit from:
- tricyclic antidepressants (such as amitriptyline or nortriptyline)
- gabapentin or pregabalin
- tramadol or other opioid-like medicines (such as morphine)
- serotonin-norepinephrine reuptake inhibitors (such as venlafaxine or duloxetine)
- gels or creams that include a local anaesthetic such as lidocaine
Acupuncture and TENS
Some patients find things like acupuncture or transcutaneous electrical nerve stimulation (TENS) helpful as well.
Studies have shown that non-drug therapies can help to reduce pain levels and enhance pain coping. These include:
- activity pacing
- cognitive behavioural therapy
These self-management strategies can help you to improve your function so you can do more and enjoy life more.
Figueroa-Romero C, Sadidi M, Feldman EL. Mechanisms of disease: The oxidative stress theory of diabetic neuropathy. Reviews in Endocrine and Metabolic Disordorders. Dec 2008;9(4):301-14.
Martin CL, Albers J, Herman WH, et al. Neuropathy among the diabetes control and complications trial cohort 8 years after trial completion. Diabetes Care. Feb 2006;29(2):340-4.
National Institute of Diabetes and Digestive and Kidney Diseases. National Institutes of Health information. NIH Publication No. 08–3185, February 2008. Rashiq S, Schopflocher D, Taenzer P, Jonsson E, (eds). Chronic Pain: A Health Policy Perspective, Wiley Blackwell, October 2008.