One of my earliest memories is of my great grandmother. I was playing with some toy trucks on the floor beside her and she was in a wheelchair. I didn’t know it at the time, but she couldn’t see me and was probably in a fair amount of pain. Years later I found out that diabetes had taken her sight and also her ability to walk. Diabetes was once a less common disease, but is now considered by some to be “America’s largest healthcare epidemic.” Unfortunately, it only looks to get worse as 57 million Americans are currently thought to have “pre-diabetes”.
While my great grandmother died many years ago, I now see and treat patients with neuropathic pain on a daily basis. Since November is American Diabetes Month, and diabetes happens to be the most common cause of neuropathy in the US, this article will focus primarily on diabetic neuropathy; what is it? what causes it? how is it diagnosed? Part two of this article will focus on natural ways to manage the pain associated with neuropathy.
“Neuropathy” is the term used to describe disease or damage of the nerves in the body. The peripheral nervous system is made up of the nerves that branch off of the spinal cord and go to all of the parts of the body, like the branches and twigs on a tree. It is the information superhighway of our body. It promotes our survival by detecting changes in the outside world and coordinating and controlling our body’s response to those changes. The term used to describe disorders of these nerves is Peripheral Neuropathy (PN).
A person with peripheral neuropathy may feel many different symptoms depending on what type of nerve damage they have. Our nerves contain large and small fibers (axons) surrounded by insulation called myelin. Some types of neuropathy affect one type of fiber more than the other, and others affect the myelin more than the axons. Large fiber neuropathies often result in weakness, decreased sensation, poor balance and decreased reflexes. These types of neuropathy are sometimes discovered on exam before a patient is even aware there is a problem. Small fiber nerves relay information about pain and temperature and also control many of the organs in our body. Patients with small fiber neuropathies tend to complain of burning hot pain, coldness, biting pain and pins and needles. Small fiber nerves also control our glands and organs, so damage to them may result in organ problems such as skin discoloration, changes in sweat activity, impotence, swelling, indigestion/ulcers, irregular heartbeat and light headedness or fainting.
People with peripheral neuropathy often complain of:
- Burning feet at night
- Numbness, tingling or shooting pains
- Hot or cold feelings in the hands or feet
- Restless legs”
- Having to “shake out” their hands at night
- Dropping objects
- Hands and feet that feel swollen
- Poor sense of balance
- Cuts and scrapes taking longer to heal
- Pain when someone touches them
Odds are that if a diabetic lives long enough, they will eventually develop neuropathy. 25 years after being diagnosed, 50% of diabetics have neuropathy. Certain risk factors accelerate the timeframe in which nerve damage occurs. The risk of a diabetic developing nerve damage increases with patient age, the length of time they have had diabetes, smoking, high blood pressure, and high cholesterol. Certain medications, especially statins (ex: Lipitor, Crestor, Zocor, Vytorin) are known to cause neuropathy as a potential side effect. When a diabetic takes statins, the risk of developing nerve damage increases substantially.
Diabetes damages nerves via several different mechanisms, which are still not completely understood by science. Increased blood sugar levels result in nerve swelling. Swelling compresses the tiny blood vessels that wrap around the nerve. The resulting microscopic loss of blood flow to the nerve results in pain and nerve damage due to decreased oxygen delivery. In addition, many diabetics have a defective enzyme that prevents essential fatty acids (good fats) from being converted by the body into chemicals that protect red blood cells. This makes the blood cells more brittle and they have a more difficult time squeezing through the tiny blood vessels which are already compressed. As a result, the nerves receive less blood flow and less oxygen. In addition to these mechanisms, diabetics are also prone to nerve damage from free radicals.
Frequently, it is the longest nerves in the body that show the first signs of damage as they die back from the toes towards the spine. Symptoms occur in the same pattern as if wearing a pair of socks. By the time the symptoms reach the upper calf, they begin to have problems with their fingers and hands. At this point they may resemble a “stocking and glove” pattern. Early on, it is very common for people to lose their sense of where their feet are in space, causing them to have a poor sense of balance and fall more easily. Quite often, weakness, loss of reflexes and decreased sensation go unnoticed by the patient because the brain compensates for these losses.
These subtle early signs of PN can only be detected with a proper clinical exam by a trained professional. If un-detected, or allowed to progress, many of these patients will gradually begin to experience the tingling, burning, biting, pin pricking, restless, stabbing and electrical pains associated with peripheral neuropathy. These symptoms can become very disabling and tend to be worse at night. Once they begin, they gradually get worse. Many patients will eventually become unable to walk and some may require limb amputation (removal).
The combination of poor sensation and poor circulation is what proves to be especially dangerous to a diabetic patient. Oftentimes, they can not feel small cuts and scrapes that occur to their feet. Their poor circulation means that these injuries take much longer to heal and they are less able to fight off potential infection. A small scratch can develop into a skin ulcer, which can then become infected. If allowed to progress, gangrene can develop and the toe or foot may need to be removed. Roughly 75,000 lower limb amputations are performed on diabetics each year.
A thorough history and clinical exam are the best way to screen for neuropathy. Large fiber nerves can be tested by checking reflexes, the ability to feel a vibrating tuning fork or a thin strand of fishing line (monofilament) on the skin. Small fiber nerves are evaluated by seeing how well a patient can feel a gentle pinprick or something hot or cold. Changes in heart rate and sweat activity can also be evaluated. In some cases, special testing such as nerve conduction tests or skin biopsy are required to help determine what type of neuropathy exists, and how severe it is. Once nerve disease is identified, blood work is sometimes performed to determine the cause and follow-up care. Occasionally, the first sign that a person may have diabetes is neuropathy. In this case, blood work is performed to confirm or rule out diabetes. As mentioned earlier, there are other causes of neuropathy besides diabetes, but diabetes is the most common cause of nerve damage in the US. The trick is to identify neuropathy as early as possible. The earlier on the process is, the more difficult it can be to diagnose, but it can be much easier to manage and treat. If it isn’t caught early on and becomes worse, the diagnosis becomes much easier, but the management of the neuropathy becomes more difficult.