electric shock on top of foot

by Angie
(UK)

superficial nerve entrapment on foot

For a few nights ive been kept awake with what I can only describe as an electric shock on the top of my left foot (where my laces would tie on my trainers)... I go to sleep fine but am woken around 2 with this awful stabbing pain, just like an electric shock... I am so so tired and irritable, thinking about going to my gp but im sure she will not understand whats going on. The only way to relieve this is to get out of bed and stand up, weight bearing seems to take the pain away. The area on my foot is actually sore to touch, it seems a surface pain, nothing deep in my foot... I think I might have had this occasionally before but never keeping me awake like it is now....During the day it all seems fine although today ive had a couple of "tweeks" but all is well when I stand up.. happy to try anything to help this go away...... oh im early 60's, retired but fairly active, female and ive been on oral chemo for nearly 2 years now. Cant think of anything that has recently changed, im just so so tired.

RESPONSE

Hi Angie,

I actually replied to your post, but in this section of my site I can go into more detail. If you choose to see a doctor about this and I think you should simply because of how painful your foot is, then you need to see someone who specializes in the foot. You are correct in your assumption that you GP may be clueless as to what is going on and just write it off as arthritis.

You should really read my section on midtarsal fault as I think that is where you will find answers.

The electric shock that you describe that originates from where you tie your trainers is more than likely an irritation of one of the superficial nerves that travel down the top of your foot, thus giving you sensation on the top of your foot and toes. Looking at the diagram I included, the black arrow points to the superficial nerve (yellow), while the black circle is where I think your pain is originating from.

In many instances, there will be bone spurs on the top of your foot, again, right where you lace your shoes, so if your shoes are laced too tight, or if your feet swell while you are walking, this essentially "squeezes" the nerve against the rough bone spurs and the nerve gets irritated. You then end up with electrical shocks that travel down your foot.

Without shoes or socks on, take one finger and tap it in the area where you lace your shoes and see if you reproduce the pain; if so, it is probably a trapped nerve.

Perhaps the bigger issue is why are you having this problem and what can be done to alleviate it. As I said earlier it could be from bone spurring or it could be just from tying your shoes too tight.

Now, if it is from bone spur formation rubbing on the nerve, more than likely the problem is because you have a flat foot. Not necessarily when off your feet, but when you stand up, your arch collapses. This collapsing, over time, causes a jamming effect of the two bones that make up the apex of your arch. This repeated collapsing causes excess bone growth and thus the growth of bone spurs.

The treatment for this is the use of an orthotic to keep the feet from over collapsing, in doing so, the bone spurs are not going to disappear but worsening should not occur.

I would be remiss if I did not mention the fact that if you happen to have a very high arched foot, that too can cause a nerve entrapment since the high arch leaves very little "wiggle room" for you to lace your shoes with any degree of tightness.

As I said in your post that I answered, if you are in as much pain as you state and it turns out you have a nerve entrapment, which is the nerve embedded in scar tissue, then a cortisone injection may be very helpful.

Additionally, some people present with the same type of symptoms and in addition to the nerve irritation may also have a ganglion cyst and to a lesser extent an inflamed bursal sac (bursitis). These two conditions should also respond to a cortisone injection.

In real severe cases of this type of pain that do not respond to conservative therapy, surgery may be indicated. Depending on the actual diagnosis certain procedures may be performed to try and dissect the nerve out of the scar tissue and free it up. If there is excessive bone spurring, that too may be removed. If there happens to be a ganglion, that may be removed as well.

So I hope you can see that you need an accurate diagnosis in order to deal with this problem and the only way you are going to get that is to see someone who specializes in the foot.

Marc Mitnick DPM
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