Ulnar neuropathy

By Abhijit Menon-Sen <ams@toroid.org>

2009-12-28

For the past several months, I have suffered from a damaged ulnar nerve in my left arm. I'm recovering slowly as the nerve regenerates, but it's been long enough that I am no longer impaired by the injury.

My best guess about how the nerve was damaged in the first place is that it happened when I twisted my elbow because my mother's well-meaning but dim-witted Golden Retriever puppy jumped on me while I was doing pushups back in June. I woke up one morning (a few days afterwards) with a mild tingling in my little finger. The tingling intensified rapidly, and the finger became numb the next day. The pattern of numbness in the little finger, outer half of the ring finger, and outside of my palm made it obvious that the ulnar nerve was affected. When the numbness turned into stiffness a day later, I sought medical advice.

I don't get along very well with doctors, so "medical advice" meant speaking to my physiotherapist friend Gautam, who happened to be in town at the time; but even he advised me to see a doctor. I went to a general physician, who had me take a blood sugar test to eliminate diabetes as a possible cause (which it did), and asked me to see a neurologist soon. I reluctantly went to see one at the nearest hospital a day or two later.

Nerve conduction study

After much poking and prodding, he said more or less what Gautam had already told me: I had "cubital tunnel syndrome", where the ulnar nerve was compressed at the elbow. There was nothing for me to do but wait and rest my arm to avoid making things worse. He also asked me to undergo a study to measure the nerve conduction velocity in the affected nerve.

The test involved zapping various points along my arm with a current and measuring how long it took for the signal to travel down my arm by means of conductive pads stuck to my fingers and elsewhere on my hand. My arm would twitch involuntarily each time a current was applied. As the probe was applied to different spots on my arm, I could feel different fingers contracting each time, and I realised the median nerve was being used as a control to compare the ulnar nerve's responses against. The procedure had to be repeated a few times, because the pads kept slipping off. It wasn't pleasant, but wasn't exactly painful either. (The worst part was that the computer I was hooked up to was running Windows.)

The neurologist barely glanced at the resulting chart (prescribing tests that the in-hospital labs provide seems to be SOP for doctors consulting at this hospital), but the test did confirm that the impingement was at the elbow and not the wrist (which would have been potentially much more serious), and relatively minor (no ulnar claw for me, thanks!).

Recovery

The tingling never returned with the same intensity, and over the next several days, the fingers gradually became less stiff, and a measure of sensitivity returned to them in the following weeks. I couldn't use my left hand to type at all for several days. Even when my fingers became less stiff, folding my elbow to put my hand on the keyboard would make my arm sore and cause shooting pains after a very short while. I followed the neurologist's advice and took Adenosylcobalamin (vitamin B12) supplements for a month. I don't know what effect they had, if any at all.

A few weeks later, things reached the point where I could type for up to half an hour at a stretch before I needed rest, but it felt awkward and slow. I did exercises to keep my finger muscles in shape (and grasping things with a finger that can't quite feel them is a weird experience), and they seemed to help. Bumping the outside of my hand on the table was still quite painful, but the numbness was noticeably reduced. After some initial improvements, however, my hand seemed to reach a steady state, and I could no longer notice a daily increase in sensitivity.

(I'm told that regenerating nerves grow at 1mm/day, but I don't know if the ulnar nerve needs to grow from its connection to the spine all the way to my fingers, or just from my elbow downwards. Either way, that's a couple of years before I can hope to see any real change.)

Six months later, the affected area still feels a little wooden, but I have regained the mobility I had lost. There is no consistent pain, and despite the occasional twinge, typing is no longer a problem.