Cold hands, slowed conduction velocities and prolonged latencies

"Cold hands, warm heart." That's what we say to patients we examine who complain about our cold hands. It's essentially a meaningless phrase. Yesterday I found out my cold hands meant prolonged latencies and slowed conduction velocity of the median nerve at the wrist suggesting carpal tunnel syndrome.

I've been on the neuromucular rotation for 3.5 weeks now and I'm slowly learning how to do nerve conduction studies. These are the tests neurologists use frequently to help confirm diagnoses such as carpal tunnel syndrome, guillain barre, ALS, or various nerve entrapment syndromes from peripheral nerve compression.

After doing some studying and observation, the first patient I did a nerve conduction study on was a very nice woman who had possible tarsal tunnel syndrome. This condition involves entrapment of the tibial nerve were it runs in the ankle causing pain and weakness primarily in the first three toes and ankle. She had some trauma of her ankle many years prior and ankle surgery 3 years prior, but continued to be plagued by ankle and foot pain and weakness.

I did her nerve conduction studies with intermittent supervision from one of the techs. It was a cold winter morning in Chapel Hill so while her feet were warming up we made small talk about her life in Wilmington on the eastern coast.  She admitted she had some apprehension about the study as her physician told her the shocks from the nerve conduction study would hurt, and the needle from the EMG would be even worse. I tried to put her at ease. I did not tell her that she was the first patient I would ever do this study on, but I think she figured this out soon. I was slow in arranging the electrodes, fumbled with the wires, and mislabelled her sites in the computer. The tech very patiently corrected these errors and I completed the studies with his help. A study which should have lasted 30 minutes dragged on for about 90, but I was lucky that my patient was very easy going, had good anatomical landmarks, and enjoyed my small talk. Also the schedule was light as most people cancelled their appointments since the forecast was predicting snow.  She tolerated the shocks (or stimuli as we like to call them) very well with minimal pain. The results of the study were essentially normal in spite of her history and exam so strongly suggestive of tarsal tunnel syndrome. Her referring surgeon would now have some difficulties deciding whether to surgically release her nerve in the setting of normal nerve conduction studies. The needle EMG was an ordeal for her, but that was done by someone else as I don't have enough experience to be turning my patients into pin cushions yet...

And then in the afternoon I tried to find a med student or co-resident to be a practice patient for me to improve my skills. No one was available so I had to do the nerve conduction study on myself. This is a difficult process. You really need two hands for this study, one to apply the stimulus to the nerve, and another to press the button on the machine to give the stimulus. When I practiced on myself, my dominant right hand was occupied with the electrodes and stimulator used to do the study. I decided not to warm my ice cold hands up because I was having difficulty keeping my hand under the warmer since I only had one free hand to work the computer. The results of my right arm study were abnormal with prolonged latencies of the median nerve at the wrist and palm which is suggestive of carpal tunnel syndrome.

I showed the results to my attending since this is a requirement to move on in the rotation. If I had been more familiar with the normal values I would have thrown out the study and repeated it with warm hands. I explained that my hands were cold, but he was not sympathetic. "You have carpal tunnel syndrome Arun. These values are abnormal. Don't worry we can take you to the OR, I've done a few of these procedures before!"

I know he was just joking, but for a brief moment I was upset. I had a mental image of myself in a hospital gown with my attending standing bedside with a scalpel in his hand. I thought about how I have been fortunate to avoid significant health problems thus far through residency.  The next day I repeated the study. This time, I kept my hands under the warmer for 20 minutes. The results were normal.  So to me, cold hands means prolonged latencies, slowed conduction velocities, and occasionally false diagnoses in the EMG/NCS lab.