February 19th, 2011
The toes burn and tingle and sharp pains shoot into the legs. The bed sheets feel uncomfortable on your feet and you toss and turn, hoping to drift away into a pleasant slumber. But, the “fire-like” sensation in your toes keeps you awake. You switch positions, wiggle the toes, prop a pillow under the legs, but nothing seems to help. You can only lie in bed and watch the hours on the clock pass by.
Burning, numbness, tingling, hot and cold sensations, shooting and electrical pain are common sensations felt in the feet in individuals with painful diabetic peripheral neuropathy (PDN). Neuropathy is an abnormality of the nervous system. Diabetic neuropathy is nerve damage caused by diabetes and is described as a loss of sensation that starts in the tips of the toes and gradually works its way up the legs. Diabetic neuropathy is sometimes referred to as a stocking glove neuropathy because it progresses as if one was pulling on a stocking. Diabetic neuropathy can affect both the hands and the feet.
There are three types of nerves affected in diabetic peripheral neuropathy, sensory, motor and autonomic. Sensory nerves allow people to feel sensation, like pain, hot or cold or touch. Motor nerves control the muscles and allow movement. Autonomic nerves control bodily functions without our awareness or control. In the feet, an autonomic nervous response would be sweating. Neuropathy can affect all of these nerve group types, but sensory nerves are typically the first and most often affected.
Almost twenty-one million Americans have diabetes. About sixty to seventy percent of diabetics have some type of nerve damage and about thirty percent of diabetics over forty years of age have diabetic peripheral neuropathy (CDC, 2005). Five percent of diabetics will experience painful diabetic neuropathy and the incidence increases with age. Over forty five percent of individuals who have had diabetes for over twenty five years will experience some symptoms of PDN.
The exact cause of diabetic neuropathy is not clearly understood. Many theories exist, but the general school of thought is that high blood sugar causes chemical changes in the nerves and damages blood vessels carrying oxygen and nutrients to the nerves, impairing nerve function. A not so new theory, which is gaining in popularity is the idea that diabetics are susceptible to nerve compression. The susceptibility is thought to be due to the increased volume of the nerve from the abnormal glucose metabolism within the nerve. In layman’s terms this is as if the nerve is swelling and the surrounding tissues and ligaments are pressing on the nerves, resulting in a loss of function.
Currently, there are no treatments to reverse diabetic neuropathy and there are no treatments that will eliminate the numbness. There are, however, many treatments to decrease the symptoms associated with PDN.
There was hope of reversing or significantly improving neuropathy with medications like aldose reductase inhibitors, myoinositol, protein kinase C inhibitors, C-peptide, vasodilators and nerve growth factors. Unfortunately, the research did not show consistent or effective results.
The mainstay of medical treatment for diabetic peripheral neuropathy is to manage the symptoms with medications. For those individuals with painful diabetic neuropathy, prescription medications may be needed to manage the pain. Classic medications used for treatment include amitriptyline, desipramine and nortriptyline. These have been used to help decrease pain and to help with sleep. Fluoxetine, paroxetine, sertralene and citalopram tend to be better tolerated, but are also tend to be less effective at relieving pain.
In September of 2004 the FDA approved duloxetine, known as Cymbalta. This was the first drug approved for specifically treating PDN. Gabapentin, also known as Neurontin, has been a successful treatment for painful diabetic neuropathy. Originally approved as an anti-seizure drug, it became a popular treatment in painful diabetic neuropathy. There was a controversy surrounding this medication when the manufacturer started marketing this medication to treat PDN, which is an off-label use. Many physicians still use this drug as a treatment. A newer medication has emerged called pregabalin, also known as Lyrica. Pregabalin was FDA approved to treat pain caused by nerve damage and many feel pregabalin is superior in effectiveness and has fewer side effects than neurontin. Tegretol and Dilantin, common seizure medications, can be used in more severe cases.
Anodyne infrared therapy uses light energy to increase the circulation to the small vessels in the feet. Diodes are fit into flexible pads which can be applied directly to the skin on multiple areas of the foot. The theory is that light energy helps to increase blood flow which restores function to injured nerves. Initially released in 1994, Anodyne was met with mixed reviews, but has gained in popularity in more recent years. Some studies have shown great results with reduction in pain and relief of overall symptoms of neuropathy. Anodyne has also been used for treatment of diabetic ulcers, with some encouraging results.
Nerve decompression has been increasing in popularity in recent years as a treatment for diabetic peripheral neuropathy. This surgical treatment was initially not met with much enthusiasm. Earlier studies showed poor surgical results and many surgeons were hesitant to perform elective surgery on diabetics. A new surgical approach has been introduced and surgical success rates have improved dramatically. The theory that diabetics are more susceptible to nerve compression, may warrant decompression of those nerves to give relief of the symptoms associated with diabetic neuropathy.
There are numerous natural alternative treatment options for diabetic neuropathy. Many diabetics have had success with their use, but studies have not given consistent results showing their effectiveness. For painful diabetic neuropathy, red pepper powder can help decrease the pain experienced at night. Capsaicin is the active ingredient in chile peppers. When applied to the feet it acts as a counter-irritant and can help decrease neuropathic pain. Capsaicin can be purchased at your local drug store. Alpha lipoic acid is an effective anti-oxidant that has been shown in some studies to relieve pain associated with neuropathy. Gamma linolenic acid is an essential fatty acid, typically sold in the form of evening primrose oil. Most of the studies have shown modest results, but the possibilities are still encouraging. Side effects of long term use at higher doses may include inflammation, thrombosis (blood clots), or decreased immune system functioning. It is important to note that even if a product is labeled “natural” it does not necessarily mean that it is safe. Always talk with your physician before beginning any new supplements.
As with all diabetic complications, prevention is the best treatment. Keeping the blood sugar levels within a normal range is the most important tool in treating and preventing peripheral neuropathy. Even with tight control, most diabetics will develop some level of neuropathy. Considering the severity of the complications associated with neuropathy (ulcers, infections and amputations), the associated pain in PDN, tight blood sugar control is of the utmost importance. Along with a healthy diet, exercising for 30 minutes each day will also help to increase circulation and stimulate the growth of new vessels, which may help slow the progression of neuropathy.
Treating painful diabetic peripheral neuropathy is very difficult and many of the above mentioned therapies should be tried and combined. Don’t expect any “cures” and make sure you give each therapy a chance to work. It is recommended to talk with your physician or podiatrist to discuss these treatment options.
Christine Dobrowolski, DPM is a podiatrist and owner of Northcoast footcare, Inc an online resource for foot care products and foot health information.
To learn more about diabetic foot care and peripheral neuropathy, visit NorthcoastFootcare.com/PDN
Tags: diet, FDA
Entry Filed under: DIABETES