Neuropathy—a disorder of the peripheral nerves—may not get as much press as obesity or cancer, or even fibromyalgia. However, it is a condition that affects approximately 20 million Americans.

Peripheral neuropathy has always been present, but has not received much attention. Its extent and importance have not yet been adequately recognized. It is apt to be misdiagnosed, or thought to be merely a side effect of another disease like diabetes, cancer, or kidney failure. The development of new therapies has, unfortunately, been slow and underfunded.

NEUROPATHY BASICS

There are many causes of neuropathy. Approximately 30% of neuropathies are "idiopathic," or of an unknown cause. In another 30% of cases, the cause is diabetes. Other neuropathy causes include autoimmune disorders, tumors, heredity, nutritional imbalances, infections, or toxins.

Some types of peripheral neuropathy can be cured, but most cannot. However, many can be helped. Therapy is directed at treating the underlying disease and at improving the symptoms with the right medications. An experienced neurologist can help patients feel more comfortable and can greatly improve their quality of life. But it is extremely important to get to an experienced neurologist as soon as you notice the symptoms before the disease has a chance to cause too much permanent damage.

Peripheral neuropathy symptoms and signs can vary in how they begin. Some neuropathies come on suddenly; others occur gradually over many years. Three types of peripheral nerves are affected, and symptoms depend on these nerves and their location:

1. sensory nerves: affect sensation;
2. autonomic nerves: affect internal organ functions; and,
3. motor nerves: affect muscles.

Many types of neuropathy affect all three types of nerves to various degrees, but some affect only one or two.

Here are some neuropathy symptoms and warning signs that your patients may experience:

Weakness in the Arms or Legs

Legs: Usually caused by damage to the motor nerves, leg symptoms often include difficulty walking or running; a feeling of "heaviness" in your legs; finding it takes a lot of effort just to climb the stairs; and stumbling or tiring easily. Muscle cramps may be common. Arms: In the arms, you may find it difficult to carry groceries, open jars, turn doorknobs, or take care of your personal grooming. A common frustration is dropping things.

Numbness, Tingling, and Pain

Sensory nerves, when damaged, can cause various symptoms. Early on, there may be spontaneous sensations, called paresthesias, which include numbness; tingling; pinching; sharp, deep stabs; electric shocks; or buzzing. These sensations are usually worse at night, and sometimes become painful and severe. Patients also may experience unpleasant abnormal sensations when they touch something; these sensations are called dysesthesias because they are caused by stimuli. Or, they may find themselves feeling nothing at all—in this case experiencing anesthesia, a lessening or absence of sensation.

Impaired Sense of Position

When patients lose the ability to "sense" or feel their feet, they may find themselves being uncoordinated because when they walk they are not sure about where their feet are placed. Patients may find themselves walking differently without really knowing how or why they are doing so. Chances are they have either widened their style of walking (in an unconscious effort to keep their balance) or they may be dragging their feet.

DIABETIC EFFECTS

When talking about diabetes, people usually focus on the direct effects of a person's blood sugar level. In addition, some common conditions that people do associate with diabetes are sensory neuropathy, retinopathy, nephropathy, and amputations. One of the conditions that we might not associate with diabetes is the changes in connective tissue that lead to a loss of range of motion. This occurs when collagen binds to glucose, resulting in glycosylated collagen fibers that act differently from regular collagen fibers. This causes a stiffness that is primarily manifested in the feet, atrophic changes in the skin, as well as loss of range of motion of the ankle and in the tarsal bones of the foot. This is something that PTs can intervene in if we recognize or assess it correctly.

Sensory neuropathy is something we readily associate with diabetes. However, there is also a motor component to that neuropathy—it is subtle, and, certainly, sensory nerves are much more likely to be involved than motor nerves. However, there is a weakness that tends to manifest itself more in the distal muscles of the foot and ankle. It is significant enough that patients have changes in gait and balance, which PTs can easily treat with exercise. However, there is limited research to show the effectiveness of exercise. The last thing that people might not associate with diabetes is the memory or cognitive changes that happen. These are also very subtle, and they tend to have more to do with the speed of processing information and with complex problem-solving.

Autonomic neuropathy is neuropathy that affects the autonomic nervous system in the body. The autonomic nervous system is what regulates our heart, digestive tract, and all of the things that we don't think about—things that are automatic and do not require conscious effort on our part toward making them work. When we have a neuropathy of the autonomic nervous system, we do have adequate baseline functioning of those organs. However, we do not respond to any stimulus that might cause a change in function. For example, when someone exercises, takes a deep breath, or holds their breath, you would expect there to be an increase or decrease in the heart rate. What happens in people who have autonomic cardiac neuropathy is that their heart rate just does not change. If they are exercising, breathing deeply, or holding their breath, or if they stand up suddenly, their heart rate stays very constant.

This is actually a problem, because our bodies are designed to respond to these stimuli; if we change our breathing, our heart rate responds accordingly. And when we do not have that change, it puts a lot of stress on the cardiac system. In addition, people can have underlying ischemia of the cardiac muscle that really has never been diagnosed. People may be less likely to have symptoms of chest pain or angina because of neuropathy. Diagnosing cardiac neuropathy requires that they have to get hooked up to an electrocardiogram (ECG) machine and go through a series of breathing or exercise tests; it is not an easy diagnosis, and there is also very little information in the literature on what the standards are for diagnosis. If PTs are the ones saying, "Let's start an exercise program," we need to know that if the patient is diabetic, then there is a possibility that there is a neuropathy that affects the cardiac system. Therefore, we need to be more cautious than we would be with someone who does not have diabetes.

REHABILITATIVE OBJECTIVES

Physical therapy may be helpful in maintaining strength, mobility, and function regardless of the underlying cause of peripheral neuropathy. The objectives of physical therapy include:

• Maintaining a range of motion—passive range of motion exercises consist of progressive stretching.
• Strengthening muscles—this includes exercising against increasing resistance, use of weights, and isometric exercise.

PTs also can recommend braces and/or splints to enhance balance and posture. Splinting also can be used in the treatment of compression mononeuropathies, such as carpal tunnel syndrome.

Occupational therapy also is instrumental in helping patients cope with the functional, vocational, and social impact of peripheral neuropathy. Goals of occupational therapy include: improving sensory-motor skills; teaching self care activities; and teaching the patient safety issues (for example, paying more attention to the terrain when walking since falling or tripping may pose a risk for patients with peripheral neuropathy).

Tracy Suheman, PT, is a staff physical therapist at Performance Physical Therapy in Tustin, Calif. For more information, contact .