Getting on your nerves: research suggests that numbness in your feet may signal a precursor to diabetes, but you can halt neuropathy in its tracks
Your feet tingle or go numb when you sit or lie down. And, what started as a tingling in your toes has now moved up to your ankles, as well. You grow anxious. It’s time to get some answers.
The symptoms may be a sign of sensory peripheral polyneuropathy (PN). Sensory PN has a myriad of potential causes, the most common in the U.S. being diabetes. While diabetic PN is most prevalent in people who have had diabetes for at least several years, researchers are finding out that neuropathy may occur in people with elevated bloodsugar (glucose) levels that are not high enough to be called diabetes.
For example, a study published in the August issue of the Archives of Neurology suggests that impaired glucose tolerance (IGT) may be associated with a chronic idiopathic axonal polyneuropathy, such as sensory PN. People with IGT have above-normal blood-sugar levels but not high enough to be diabetic, and the study authors noted that neuropathy associated with IGT may be the earliest detectable sign of abnormal glucose metabolism, a precursor to diabetes.
“What is now being understood is that you don’t have to be frankly diabetic to have polyneuropathy,” said Kerry Levin, M.D., head of Cleveland Clinic’s Neuromuscular Disorders Center. “It certainly is a warning call, especially for the overweight patient, that he or she is headed quite clearly toward a frank diabetic state if you don’t take steps to improve your health.”
WHAT’S CAUSING THE SENSATION?
Sensory PN often begins in the toes and progresses gradually to the feet and ankles. In addition to numbness and tingling, symptoms may include severe pain and a burning sensation. In advanced cases, sensory PN can migrate to the knees and fingers. Often, the symptoms progress in both legs simultaneously, and may be less noticeable when you’re on your feet and more prominent when you rest.
Some causes of sensory PN, including diabetes, are preventable. Diet, weight loss and exercise can lower your risk of diabetes, and if you’re diabetic, tight control of blood sugar can minimize the disease’s effects on nerves. Other conditions–kidney disease, liver disease, spinal conditions, rheumatoid arthritis and systemic lupus–may cause PN and require more extensive treatment.
SEEK AN EVALUATION
Because of the myriad of potential causes of sensory PN, promptly seeking a medical evaluation is critical to identifying the underlying cause of the neuropathy and halting its progression. “Any time symptoms are persistent and not natural, that’s the time to see your doctor about the symptoms and what they might mean in regard to your overall health,” Dr. Levin said.
If a neurological exam and medical history support a diagnosis of sensory PN, the neurologist will perform an electromyography (EMG), a test that identifies nerve damage. If damaged nerve fibers are too small to be detected by a standard EMG, the neurologist may recommend more specialized tests.
While no drug has been proven to reverse the effects of diabetic PN, the anti-seizure drugs gabapentin (Neurontin) and pregabalin (Lyrica), and antidepressant medications such as amitriptyline (Elavil) and duloxetine (Cymbalta) may effectively treat pain from PN.
CAUSE FOR CONCERN
Loss of sensation in your feet can impair your balance and walking ability and raise your risk of falls. It also can make it difficult to keep your feet on the pedals of your vehicle, raising your risk of accidents.
Most importantly, diabetics who lose sensation in their feet cannot recognize when they’ve suffered a foot injury, and cuts can go unnoticed and become infected. Poor blood circulation caused by diabetes also limits the body’s ability to heal foot wounds and fight infections. If you have diabetes, check your feet and toes daily for any injuries, and notify your doctor if you hurt your foot.
WHAT YOU CAN DO
* Avoid excessive alcohol consumption, which may contribute to peripheral neuropathy (PN) and malnutrition, which leads to vitamin deficiencies that play a role in PN.
* If you smoke, quit. Smoking can worsen PN symptoms.
* Call your doctor if numbness, tingling, pain or burning in your feet and legs persists and worsens.
* Change your lifestyle to prevent diabetes, a leading cause of neuropathy. Losing 5 to 10 percent of your weight through a low-fat, low-calorie diet and getting 30 minutes of moderate-intensity exercise a day has been shown to lower diabetes risk.
* If you have diabetes, closely monitor your blood-sugar levels, check your feet daily for injuries and notify your doctor promptly if you hurt your foot.
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