DEAR DOCTOR K: I have peripheral neuropathy. I know that people with diabetes often get neuropathy, but I’m not diabetic. What else can cause this condition? And what can I do about it?
DEAR READER: Neuropathy is a medical term that means nerve damage. The type of nerve damage that people with diabetes get involves specific nerve fibers in all nerves, particularly the nerves that travel to the legs and feet. (There are other conditions in which a single nerve leading to the legs and feet is pinched, causing pain. An example is what is often called a “slipped disk” or “herniated disk” in the lower part of the spine).
The symptoms of peripheral neuropathy include numbness and tingling. Some cases cause burning, shooting or stabbing pain. When the doctor does a physical examination and touches your feet and lower legs with something as light as a feather (like some cotton), you may not feel it. However, you will feel it if the cotton touches your skin in the thigh or elsewhere in the body. You may also lose sensation to a pinprick in the lower legs and feet, but not the rest of you.
Diabetes is the most common cause of peripheral neuropathy. But neuropathy can result from other causes as well. These include:
— Excessive alcohol intake.
— Hypothyroidism. In this condition, the thyroid gland does not produce enough thyroid hormone.
— Amyloidosis, a disease in which an abnormal protein accumulates in the body.
— Vitamin deficiencies, particularly vitamin B1, B12 and folate deficiency.
— Infection with human immunodeficiency virus (HIV).
— Critical illness, particularly if you develop a severe inflammatory response to infection.
— Guillain-Barre syndrome. This uncommon autoimmune disorder damages the peripheral nerves.
— Chemotherapy cancer treatment.
Diagnosing peripheral neuropathy is best done by electromyography (EMG) and nerve conduction studies (NCS). Such testing often is not necessary, as your symptoms, your medical history and your doctor’s physical examination make the likelihood of diagnosing peripheral neuropathy high enough that such testing is unnecessary.
Treatment of peripheral neuropathy begins with treating the underlying cause of the condition. For example, let’s say your neuropathy is related to heavy drinking. You should severely restrict, or better yet abstain, from alcohol. If your neuropathy is caused by hypothyroidism, treatment with replacement doses of thyroid hormone should help.
The other goal of treatment is to relieve symptoms. In particular, treatment targets pain caused by peripheral neuropathy. Several medications can help. Gabapentin, an anticonvulsant medication, is usually effective. Tricyclic antidepressants can also effectively relieve pain.
Finally, while neuropathy itself causes pain, it (strangely enough) reduces sensitivity to pain caused by outside injuries. This makes you particularly vulnerable to foot damage. If you develop a cut or sore on your foot, without pain to alert you, you may not even notice the injury. Untreated, a simple wound may become severely infected. To prevent this, carefully check your feet every day and treat any foot injury immediately.
Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.