Carpal tunnel syndrome (CTS) is technically a “pinched nerve” in the wrist (carpal tunnel) that results in numbness, tingling, and later, weakness in the distribution of the median nerve (thumb, index, 3rd, and half of the 4th finger). In addition to the median nerve, there are 9 tendons and their sheaths, a network of blood vessels, the joint capsules that pass between the the bony “roof” and ligamentous “floor” of the carpal tunnel. Any condition that distorts the shape of the tunnel (inflammatory conditions like rheumatoid arthritis, ganglion cysts, bony spurs, or conditions that result in swelling like overuse, pregnancy, taking birth control pills, hypothyroid, obesity, and/or conditions that create neuropathy like a pinched nerve in the neck, shoulder, or elbow, diabetes and post-chemotherapy) can result in median nerve irritation. The carpal tunnel naturally changes its shape when we flex and extend the wrist, so occupations that require wrist bending (especially if it’s prolonged and a fast pace is required) such as carpentry (especially the use of vibrating tools), serving tables, assembly line work, typists, and even sleeping at night with the wrist bent can result in CTS.
The diagnosis can be tricky because of all the possible causes (of which, some are described above) and to make matters even more challenging, there can be two, three, or more of the causes all contributing to the problem at the same time! In the clinic, there are certain positions to test how long (in seconds) it takes for the numbness, tingling, and/or pain to occur when you place the wrist in extreme flexion or extension. Your doctor will compress the carpal tunnel (and nerve pathways at the elbow, shoulder, and neck), as well as tap over the carpal tunnel with a reflex hammer creating a “funny bone” sensation usually into the 2nd or 3rd finger. Blood tests for rheumatoid (and other inflammatory) arthritis, diabetes and thyroid dysfunction are very helpful when trying to differentiate between several possible causes. An electrical conduction test called electromyogram (EMG) and nerve conduction velocity (NCV) can also be very helpful in determining the severity of CTS.
So the question
is, can you “self-diagnose” CTS? The answer is: sometimes. However, with
that said, if the symptoms are “classic” (numbness/tingling in the
thumb, fingers 2-4, which shaking and flicking your fingers relieves at
least partially; it’s waking you up at night especially, if a night
splint helps reduce the frequency of waking and intensity of numbness),
then you “probably” have CTS. Here are some common questions included in
a CTS questionnaire that doctors of chiropractic often use to assist
with the diagnosis: SYMPTOM SEVERITY (score each on a 0-4 scale): 1)
Pain severity at night? 2) Nighttime frequency of waking with pain? 3)
Amount of daytime hand/wrist pain? 4) Frequency of daytime hand/wrist
pain? 5) Duration (in minutes) of daytime pain/numbness? 6) Severity of
numbness? 7) Severity of weakness? 8) Tingling intensity? 9) Nighttime
severity of numbness or tingling? 10) Nighttime frequency of numbness or
tingling? 11) Difficulty grasping / using small objects like keys or
pens? FUNCTION SEVERITY (0-4 scale): 1) Writing. 2) Buttoning clothes.
3) Holding a book while reading. 4. Gripping of a telephone handle. 5)
Opening jars. 6. Household chores. 7. Carrying grocery bags. 8. Bathing
and dressing. The maximum score for SYMPTOM SEVERITY is 11x4 = 44 and
for FUNCTION 8x4 = 32. To determine the percentage, divide your score by
76 (the maximum possible) and multiply it by 100. In general, scores
>50% may be indicative of CTS. However, as previously stated, a
definitive diagnosis must include a detailed history, examination, and
sometimes special tests. Therefore, it is important to see a doctor of
chiropractic if you suspect you have CTS.