Nerves are designed to carry sensory signals up the spinal cord into our brains for interpretation and back down again. When a nerve is damaged, however, the process can go haywire. A neuropathy — a state of pain, numbness, or weakness — develops when one nerve or a lot of nerves are damaged due to any number of causes: genetic factors, viral infections like Lyme disease, herpes zoster (the virus that causes chickenpox and shingles), or HIV, diabetes, chemotherapeutic agents, or radiation treatments.
According to the Foundation for Peripheral Neuropathy, an estimated 20 million Americans live with some form of peripheral neuropathy. The most common form is diabetic peripheral neuropathy, which afflicts about 20 million Americans.
Neuropathy can cause loss of sensation or motor function as well as pain, notes Ajay Antony, MD, assistant professor of pain medicine and anesthesiology at the University of Florida in Gainesville. Classic symptoms are numbness, the sensation of burning, or a feeling similar to pins and needles, notes Jianguo Cheng, M.D., professor and program director at the Cleveland Clinic Foundation Department of Pain Management.
Pain, which is difficult to localize, is another symptom common to neuropathies, Antony says. “Neuropathy varies in severity,” Antony explains. “There’s an infinite range of how much a patient is affected.”
One of the most common neuropathies is diabetic neuropathy — a result of too much glucose in the bloodstream, which damages the nerves. Other neuropathies include postherpetic neuralgia, a pain condition resulting from the shingles virus, and ulnar neuropathy, which may result from compression of the ulnar nerve in the elbow. There are many more types.
Symptoms of neuropathies can vary greatly depending on the underlying cause, experts say. That’s why knowing the cause is important when one is thinking about treatment.
Find out how much you know about neuropathic pain by taking the following quiz.
1. Diabetic neuropathy tends to occur in people’s feet.
True or False
2. A bulging spinal disc can lead to a neuropathy in the lower extremities.
True or False
3. Neuropathies are easy to treat.
True or False
4. All neuropathies are quite painful.
True or False
5. Which of the following might help if you have a neuropathy?
A. Lowering your hemoglobin A1c if you have diabetic neuropathy.
B. Trying a systematic medication such as Lyrica or Cymbalta.
C. Topical creams like capsaicin or lidocaine.
D. Nerve blocks or spinal cord simulation.
E. All of the above.
(Scroll down for the answers.)
1. True. Diabetic neuropathy is a very slow onset problem in which over time a patient may develop progressive loss of sensation, usually in his or her feet, Antony says. It may progress to pain in the future, he notes, but that often takes decades. To reverse a diabetic neuropathy, the best thing to do is get your blood sugar under control because it’s the excess glucose that damages the nerve.
2. True. A bulging disk can compress the nerve roots in the spine and lead to a neuropathy, notes Antony. Arthritis could have the same effect.
3. False. Although there are many systemic medications out now to treat neuropathies — including pregabalin (Lyrica) and gabapentin (Neurontin) — the condition is still difficult to treat, Antony says. His focus is on spinal cord stimulation, an invasive treatment that is reserved for the most severe cases of neuropathic pain. For such patients, a device implanted near the spine modulates the pain signal coming from the peripheral nerves.
4. False. Take diabetic neuropathy as an example. Some people with the condition only experience a loss of feeling that is not much of a burden on their lives, says Antony. But for others, the condition is extreme. If you have a neuropathy, be aware of the term “allodynia,” which refers to pain caused by what would typically be a non-painful stimulus, like putting on a shoe or drying off with a towel.
5. E. If you are diabetic and have a neuropathy, lowering your hemoglobin A1C can help. Hemoglobin A1C is a marker of glucose control over several months. “It’s high glucose in the blood stream that directly damages the nerves through a process called non-enzymatic glycosylation,” Antony says.
Systemic medications like Lyrica, Cymbalta, and Neurontin may be effective for some, Antony says. Creams like capsaicin or lidocaine can also help.
Very often, combination therapies are needed, he says.
It’s also critical to take anti-viral medications within the first five days of infection with the shingles virus (herpes zoster) to prevent future development of postherpetic neuralgia, notes Cheng.
Nerve blocks and more invasive treatments like spinal cord stimulation can be used in more severe cases, Antony says.