Dr. Conway McLean, Journal columnist

Nerves are interesting structures with a unique function and very special physiology. Their ability to transmit information nearly instantaneously is unmatched in the biological world and it’s essential for mammalian life. This capacity for nerve impulse transmission is what allows us to walk and talk, to think and see, to hold a cup of coffee, and so much more.

How these thin-walled, delicate structures are able to do so is fascinating, and incorporates such sundry topics as physics, chemistry, and, of course, biology. But going into any detail is beyond the scope of this treatise. Suffice it to say, nerves function like no other tissue type. And they don’t do well with any physical stress or pressure, whether it’s a pulling phenomenon or a pinching process.

Everyone has heard of a nerve getting pinched somewhere in the body and the resulting pain. Carpal tunnel syndrome is a very common example of this phenomenon, whereby a nerve in the wrist becomes trapped, altering the normal chemical changes that are needed for signal transmission. Any time a nerve is injured, there is going to be numbness or some reduction in sensation in the area of skin supplied by the nerve that was damaged.

There is a very different result when these essential structures are running to a muscle. When a motor nerve, one that works a muscle, is the subject of some insult, the muscle it goes to will be less effective. Or, if a sufficient number of nerve fibers were damaged, paralysis will result. If it’s the nerve on the outer side of the lower leg just below the knee, weakness of the muscles in front of the leg will result and a drop foot deformity will be produced. The foot will tend to drag during gait often leading to a fall.

Another nerve disease most of us have heard of is neuropathy, a very general term which means simply “nerve problem.” This label can be applied to numerous conditions. Many are afflicted with idiopathic neuropathy, meaning we just don’t know why they have it. But the term is most often associated with the nerve changes of diabetes. This all-too-common disease of rising blood sugar levels leads to a dying-back phenomenon of the nerves farthest from your core. This equates to a loss of function of the tiny skin nerves of the toes. Sadly, this is usually a progressive process meaning it spreads insidiously, gradually, upwards. With time, nerve changes in the hands may be seen as this dying-back phenomenon spreads inward.

The nerve changes seen in diabetes is a polyneuropathy, meaning many nerves are affected. In contrast, neuritis is inflammation of a specific nerve which can be caused by various things, from an infection to an injury, some autoimmune disorders, even a vitamin deficiency can lead to an acute inflammation of some particular nerve tract. The term itself “neuritis” tells you this problem is one of an inflammatory process since ‘-itis’ literally means “inflamed.”

Unfortunately, neurology is not one of our more advanced fields of medicine. There are many who have some kind of nerve problem but we are unable to determine why, much less what to do for it. Such is the case with diabetic neuropathy, which is an incredibly common problem but still not understood. There are millions of Americans with neuropathy but we don’t know why, although many theories abound.

At least we have an intervention, a therapy, which can make a difference. Precise nutritional substances, what can be thought of as specialized nerve vitamins, can slow and sometimes reverse the degenerative changes seen with diabetes, an approach being recommended by the American Diabetes Association. This method of therapy is beneficial, although what the individual feels varies greatly. Many sufferers of diabetic neuropathy have no idea, i.e. there are no obvious symptoms that these structures aren’t working. The result: there will be no pain with a skin injury and to a diabetic, that is a dangerous situation.

Because neuritis is a localized condition, the therapeutic approaches are very different. Treating the infectious organism is appropriate when a microbe is the cause but since many cases of neuritis involve inflammation, steroids are a frequent method of treatment since they work on the biochemistry of this process. These powerful anti-inflammatory meds are used in many situations, either orally, intravenous, or injected into the area of the inflammation.

Most nerve pathologies produce certain distinctive types of pain. Burning, tingling, or shooting sensations can be the result of both neuritis and a polyneuropathy. Numbness will be noted of the area of skin supplied by the injured nerve. This can lead to difficulties with balance and stability; consequently more falls occur in the presence of neuropathy.

The research on neuropathy is on-going but many questions remain. And many individuals with diabetes suffer an amputation of a foot or leg because of their neuropathy…..they don’t feel the pain of a skin injury. Even brain function, summarized as cognition, can be affected by neuropathy. Many have been told they have neuropathy without sufficient evaluation. Being educated on the presence of this pathology is important. If you have similar signs or symptoms, have it checked out. What you don’t know can hurt you.

EDITORS NOTE: Dr. Conway McLean is a podiatric physician now practicing foot and ankle medicine in the Upper Peninsula, having assumed the practice of Dr. Ken Tabor. McLean has lectured internationally on surgery and wound care, and is board certified in both, with a sub-specialty in foot orthotic therapy. Dr. McLean welcomes questions, comments and suggestions at drcmclean@penmed.com.