Peripheral neuropathy is a common condition, affecting some 6% of adults 45 or older.
What is it, what causes it and what can you do about it?
Our nervous system consists of the central nervous system (CNS) – the brain and spinal cord – and the nerves that carry sensation to and commands back from the CNS. These nerves are the peripheral nervous system.
The peripheral nerves can be thought of as the body’s wiring system. There are sensory nerves that bring sensations of touch, temperature and pain to the CNS, motor nerves that carry commands from the CNS to our muscles and autonomic nerves that regulate bodily functions not usually under conscious control such as heart rate, breathing and gastrointestinal function.
Many things can damage nerves, some of which happen no matter what we do while others are under our control.
If sensory nerves are damaged, we may be unable to feel hot or cold or where our feet are, or we may feel numbness or tingling, or we may feel pain for no reason.
If motor nerves are involved, you will notice muscle weakness.
Autonomic neuropathy can have many effects, including drop in blood pressure when you stand up.
Because the nerves to the feet are the longest peripheral nerves, they are most susceptible to damage and usually the first to suffer. Hence, we usually notice abnormal sensation in the feet rather than higher up.
The fingers may be next.
What causes peripheral neuropathy? The commonest known cause is diabetes; the longer and more poorly controlled is the diabetes, the more likely to result in neuropathy. Another common cause is excess alcohol. Vitamin deficiency, particularly of B12 and other B vitamins, is a very treatable cause. (Oddly enough, excess B6 can also cause neuropathy!) Chemotherapy often results in neuropathy.
There are numerous diseases, too many to list, that have peripheral neuropathy as one of their symptoms.
Finally, there is that great wastebasket of “we do not know.” One of the commoner causes of peripheral neuropathy is simply aging, with no specific disease found after thorough testing.
What can you do? If you notice any of the symptoms listed above, bring it to your doctor’s attention. Verifying the presence of neuropathy is usually easily done by physical exam. If it appears likely, you should probably see a neurologist for a more thorough exam and testing.
To minimize the likelihood of developing neuropathy, eat a healthy diet with lots of fruits and veggies to get your B vitamins and minimize your alcohol intake. If you have diabetes, work with your doctors and nurses to keep it under good control.
Do not dismiss it (or let your doctor dismiss it) as simply aging. Only after treatable causes are excluded is this an acceptable conclusion.
Edward Hoffer MD is Associate Professor of Medicine, part-time, at Harvard.
What Does The Doctor Say?
By Dr. Edward Hoffer