Neuropathy, what the heck is it?

I had a reunion with a colleague the other day that brought to mind this topic. He and I first met when I sat on a prelitigation panel for potential lawsuit. This is sort of like jury duty for doctors. He was the doctor in question. The patient accused him of doing a surgery and leaving an instrument inside their foot. The surgery was a small soft tissue procedure 14 years before the alleged complication was discovered, making the possibility of malpractice extremely unlikely. Long story short, the patient had what appeared to be a needle in their foot, probably a sewing needle. This had developed an infection and required multiple surgeries to clean out the wound to address the infection.

What does this have to do with neuropathy? Everything. The first question I asked the prosecution was if the patient had neuropathy. They responded that this patient did have it. The next question was if the wound was on the bottom of the foot. Again, it was. Immediately I realized what was going on. This patient had likely stepped on a sewing needle two weeks or so before their foot showed infection. Because of neuropathy, the patient hadn't even realized that they had stepped on something. This type of thing happens all the time with neuropathic patients.

How does this happen? What is neuropathy? Maybe you were just told by your family doctor that you have it, maybe you heard an ad on TV about diabetic nerve pain. I hope to be able to explain this condition in a way that you can wrap your head around the concept and give some solutions for it.

What is peripheral neuropathy?

Neuropathy is disease of the nerves leading to malfunction of whatever those nerves control. This can happen with your ability to feel sensations, control your muscles, and even regulate your skin moisture levels or body temperature. Nerves are like the network cables of the body. They send information from the brain telling individual muscles to contract. They also receive information from the body about things that you feel, how hot it is outside, how dry your skin is, and many other things. If you sense something, it's because of the nerves in your body. 

Peripheral neuropathy is damage to the nerves, causing the nerves to either send incorrect information or fail to send it along the nerves. I grew up with landline telephones, so I hope my analogy helps even the millennials reading this grasp the concept. 

The Telephone Analogy

If phone lines are slightly damaged, it's likely that static electricity on the line will make a conversation difficult to understand. It sends a white noise along the line, making other sounds hard to hear. Eventually, if the lines get damaged enough, no signal gets through and the phone goes silent. This is how nerves work. They use chemical and electrical impulses to communicate with the brain what's going on. If they get damaged, you can see how problematic that can be. 

Peripheral neuropathy usually starts with a painful burning or tingling sensation in the feet, even when no source of heat is present. That's because the "white noise" on the line sends a message that your brain interprets as heat or pain. The more damage happens to the nerves, they eventually become unable to send signals and your brain interprets this lack of communication as numbness. If you've ever had your feet fall asleep on the toilet, you've experienced this in a temporary way. 

How Does It Happen?

Lots of things can cause this nerve damage. In America, the most common cause is diabetes, but there are lots of conditions that cause this. To name a few--age, genetics, prolonged deficiency in B-vitamins, alcoholism, syphilis, leprosy, exposure to heavy metals (isotopes, not music), and even some medications--all of these have been known to cause neuropathy.

Why Does It Happen In The Feet First?

Nerve damage happens as a random probability-based process. Anywhere along the nerve (which can be up to 3 feet in length) can be affected randomly by the disease process. The more injuries happen to the nerve, the more the nerve malfunctions. Like buying a lottery ticket, the one with the most tickets is most likely to win, the longest nerves are most likely to get affected first. Toes have the longest nerves, so most likely to be affected first, followed by fingers because they're the next longest.

Healthy Appearing Nerve

Zoomed In

Damaged Nerve

Zoomed Out
Appreciate how it builds up cumulatively along the length of the nerve

 I Have Neuropathy, Now What?

Typically, neuropathy doesn't reverse, but there are things to improve some of your symptoms and slow its progress. Other treatment options involve managing symptoms. Managing blood sugar levels is the most important step if you have diabetes. There are over the counter options as well as prescription options. I'll briefly attempt to fill you in on some of the most common options available.

Things I Can Do On My Own

Blood Sugar Control

This pretty much only applies to diabetic neuropathy. Blood sugar control in diabetics is vital. Nerves are special cells that use sugar as their primary fuel source. Because of this, they don't have the same sugar level controls as other cells, like in your liver or muscles. If your sugar is high throughout the body, it's EXTRA high inside the nerves, causing lots of damage and wrecking things inside the nerve cell. If the thing that damaged the nerves is high sugar levels, lowering it will slow down the rate that the sugar destroys the cell. Makes sense, right? Typically I've seen patients whose A1c--a lab value that uses a complex equation to estimate your average blood sugar over the last 3 months--is above 7.0%, neuropathy symptoms get worse. If it's below that, the symptoms calm down most of the time. Not always, but usually.

Nerve Health Supplements

There are supplements that you can take to give the nerve nutrients it needs to repair itself. Most supplement manufacturers would tell you that you need "activated" vitamins, meaning they're in the form your body needs to immediately incorporate into the repair process. These are expensive, but I've heard from the handful of people who have taken them that their symptoms have improved. Most of the supplements cost around $70-$100 a bottle, which lasts about a month usually. The most common brands I know of are Metanx and Foltanx.

You can also take regular vitamins, instead of the activated ones. I'm sure there are a number of supplement reps out there who would give a well-crafted response to this, but the vitamins can help. The ones I typically recommend are Vit C, Vit D, and Vit B1, B3, B6, and B12. These are to be used as directed on the labels.

There are some homeopathic remedies that you can find in health food stores. I hesitate to mention these, though. They typically are not completely benign to take. Homeopathic remedies often interact with other medications you might be taking, as I've mentioned before. Make sure to ask your pharmacist or primary doctor about possible interactions if you decide to use any of these homeopathic nerve remedies, because they aren't supplements like the above-mentioned options. I also don't know much about things like essential oils (they're not thoroughly taught in most medical schools), so be careful with what you decide to try.

Nerve Creams

There are lots of options in this area that work fine, generally. Trolamine Salicylate (both brand name and generic) is found in several formulations that are helpful, as long as used properly. Topical lidocaine can be helpful and is often found in formulations that include trolamine salicylate. Capsaicin is another ingredient that is isolated from peppers (it's what makes them hot) takes the discomfort from neuropathy away by stimulating the nerves so much initially that they turn off and stop sending the white noise along the nerve, so only big sensations get through to the brain.

Experimental Treatments

There are a few treatments out there that have shown promising results but haven't been through the rigorous (and sometimes ridiculous) testing requirements of the FDA. The one I'll touch on involves a treatment regimen of electrical stimulation (neurostim unit) and injection of local anesthestics like your dentist uses to numb your mouth. This regimen has some very strong believers, including patients I've met who swear they couldn't walk before treatment, but after a few weeks of treatment don't need a cane anymore. This is deemed experimental by your insurance, so if you want to try it, it's not gonna be cheap and you can forget asking insurance to cover it because they won't, so expect to pay cash each time it's used.

Prescriptions

The following are options you can only find with a prescription from a physician.

Neuromodulators

This class of drug--going back to the white noise on the phone line example--turns down the volume from the brain's interpretation of the nerve signals. It affects nerve-related Calcium channels (very technical, but nobody knows the exact way it works in the brain). It makes it so that the white noise disappears and only signals large enough to get through are sensed. These aren't without their drawbacks, because they deal with the brain, not just the small nerves in an affected area. They can make you sleepy (most common symptom) and make it easier to develop seizures in susceptible individuals. Newer medications are more targeted, but still have these risks. You also can't stop taking them quickly because that greatly increases the chances of adverse reactions.

Gabapentin is the most common of these medications. It is a regulated medication and is most commonly associated with drowsiness, so this needs to be managed carefully and doseage slowly increased until it has reached the effective dose.

Lyrica (pregabalin) is the other very common one in this class. It's newer and has a slightly slimmer side-effect profile, but needs to be carefully managed by your doctor.

Antidepressants

Some of these--not all--can be used to manage neuropathy. The one I've used most commonly is amitriptyline. This is a long-tested antidepressant, which has a long list of possible side-effects but in the right patient can be used for neuropathy management. Again, as with all of these options, no evidence of reversal or healing of the nerves, but improvement of symptoms has been noted.

What Should I Watch Out For Because of My Neuropathy?

This is the thing you have the most control over. Neuropathy leads to lots of complications: unknown injuries, pressure-related wounds, burns, loss of balance, dry skin, etc. Very long list. The most important thing to do is inspect your feet daily, more if possible. Looking at your feet will ensure that, unlike the example at the start of this article, you find wounds or injuries you wouldn't otherwise find. I have had to perform dozens of amputations on patients who could've avoided it by taking care of their feet or coming in immediately after a wound or injury developed. Please, please, please if you have neuropathy, look every day at the bottoms of your feet and in between your toes.

Also, use moisturizing creams, because the nerves that control your sweat glands stop working, leading to dry, weakened skin that is less flexible and easily cracks and splits. Moisturizing creams help with this.

Wear appropriate shoes. Sorry, but those stylish, super cute flats are out. Those old army boots you love hunting in? Also out. You need softer, wider, deeper shoes that prevent your toe from rubbing. Without neuropathy, you would feel a blister developing and choose to take the shoes off. With neuropathy, you don't feel a thing, so you wear a hole in your skin without realizing it. That leads to infection and surgery. Trust me, better to change shoes ahead of time than need prosthetic fillers because you're missing half your foot.

The last thing I recommend is regularly seeing a podiatrist. This is so that issues that creep up on you, like toenails getting long and cutting the skin of the neighboring toe, can be addressed soon. Generally insurance covers these visits and it sure beats you cutting your toe without realizing it because you couldn't feel the clipper cutting you and not just your nails. It's not always your choices that caused you to develop neuropathy, but once you have it you should accept it and control what you can.

Never assume something on your foot or ankle "is nothing" or "will get better." There are lots of conditions, such as Charcot Foot Disease that can easily be mistaken for other conditions like an ankle sprain or gout that have devastating consequences if misdiagnosed, so get help when needed. It's not the doctor's fault or yours that you have neuropathy, but sweeping things under the rug when you could get help definitely is something you can control. Please take care of yourself, you'll thank me for it.

Summary

There are lots of causes of neuropathy, but the end-game is the same: manage your symptoms and catch things early, so the molehill doesn't become a mountain. There are some things you can do to help, but you need to make sure your doctors are equal partners in managing this condition. We got into our profession to help people, so let us do so! Good luck with the rest of your life from this moment on.

As is typical with my articles, I've made these diagrams myself and I have no conflicts of interest.