Carpal Tunnel Syndrome Part 3. How do you diagnose Carpal Tunnel Syndrome?

“This ain’t no party, this ain’t no disco, this ain’t no fooling around”

from “Life in Wartime” by The Talking Heads

So your hand is going numb and waking you up every night.  It goes numb while you’re working on your hair, driving a car, or reading a book.  You’re pretty sure you’ve got carpal tunnel syndrome.  As a hand surgeon, what do I look for to help make the diagnosis and guide you to make a treatment decision?

Most patients initially talk about these kind of symptoms with their primary care physician.  The primary care physician can usually treat straight forward cases of carpal tunnel syndrome, but if the symptoms are confusing or severe, then they may decide to refer you a specialist.  This is where I come in.

When I see a patient that may have carpal tunnel syndrome I have several goals.  First, I try to find out if the problem really is carpal tunnel syndrome.  There are several types of hand problems that people can have along with carpal tunnel syndrome, and it’s my job to try and figure what is causing the problem that brought you in to see me.   I can usually figure this out by listening to the symptoms you have and performing a pretty simple physical exam. There are three tests that are commonly done to evaluate carpal tunnel syndrome.  The first is to tap along the course of the nerve.  If this causes a shock to go though your fingers the test is positive.  This is known as “Tinel’s” test.  A second test is to push on the nerve at the level of the wrist and see if this reproduces numbness and tingling in the hand.  This test goes by several names but most people call it by the highly original name of  the “median nerve compression test.”  A third test involves bending your wrist down and waiting 15-30 seconds to see if this causes numbness and tingling in your hand.  This is called “Phalen’s” test, named after Dr. George Phalen who was one of the  main physicians responsible for figuring out what carpal tunnel syndrome was. None of these three tests will diagnose carpal tunnel syndrome for certain, but when you combine them with the history then you can get a pretty good idea if the patient has carpal tunnel syndrome or not.

The most common problems that people have along with carpal tunnel syndrome are arthritis and a condition called “trigger fingers”.  Trigger fingers occur when the tendons in your hand get thick and they stick when they pass through a sheath in your hand.  Arthritis occurs in several areas, but the joint where your thumb attaches to your hand is the most common painful area.  I can usually get a pretty good idea which problem is causing the problems that you came to have evaluated.

Next I try and figure out how bad the carpal tunnel syndrome is. I can often figure that out from your symptoms and the exam, but this may require extra testing.  The most common test we use is called a nerve conduction study.  This is a test where a neurologist or other qualified physician tests the nerves in your hand to try and tell if the nerves are damaged and if they are damaged, how severely the nerve is damaged.  This usually requires a referral to another physician to get the test done and then a return visit to go over the test, so it’s really nice when the patients primary care physician has these tests done before I see the patient.   The nerve test can provide a lot of information.  They can give you an idea how severe the carpal tunnel syndrome is and also whether or not there are any other areas of nerve damage.  A number of patients will have compression of their ulnar nerve (the funny bone) in addition to carpal tunnel syndrome and this can change or influence your treatment decision.  However not all patients need nerve conduction studies.  Sometimes the process is so advanced and the nerve damage is so severe that the diagnosis and treatment options are obvious.

Nerve conduction studies aren’t perfect since probably 10% or so of people with carpal tunnel syndrome have normal nerve conduction studies.  The test still remains our best objective data test to evaluate carpal tunnel syndrome.

Once all the data is in, then comes the hard part, which is to decide what to do about the problem.  And that will be the focus of my next post.






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