Believe it or not, carpal tunnel syndrome is yet another “complication” associated with diabetes. Beyond simple forearm discomfort, it can be quite debilitating. Here's an overview for people with diabetes on what carpal tunnel is exactly, and what you can do about it.


What is Carpal Tunnel?

As you probably know, carpal tunnel syndrome (or CTS) is a progressively painful hand and arm condition caused by a pinched nerve in your wrist. Specifically, it affects the median nerve, which runs through the "carpal tunnel" from your hand into your forearm. The median nerve provides feeling to the palm side of your fingers and is the muscle power that powers your thumb. When the median nerve is pinched from swelling of nerves or tendons in the carpal tunnel, numbness, tingling and pain can affect the hand and fingers. It can also lead to other symptoms, like poor circulation and loss of grip strength.

The root cause of the condition is unknown, but with diabetes, researchers believe that high blood glucose levels cause the tendons of the carpal tunnel become glycosylated, which means the tendons become inflamed and excess sugars form a "biological superglue" that makes the tendons less able to slide freely -- similar to what happens in frozen shoulder.


Carpal Tunnel and Diabetes

In the general population, CTS hits between 2-3% of people, but it seems to cluster around people who are already dealing with other health challenges. The most common conditions linked to carpal tunnel syndrome are:

Diabetes. (That’s us.)

Thyroid. (That’s most of us, as diabetes and thyroid conditions are bosom buddies.)

High blood pressure. (Uh… again, common among us.)

Autoimmune disorders. (Well, that would be us type 1s.)

Is it any wonder that people with diabetes are fifteen times more likely than people without diabetes to get carpal tunnel? Research has shown that approximately 20 percent of people with diabetes will get CTS.

In fact, a few years ago research evidence was being circulated that CTS might actually predict type 2 diabetes: A study in Diabetes Care found that people who had been diagnosed with CTS were 36% more likely to be diagnosed with T2 diabetes later in life, regardless of other diabetes risk factors. However, newer research suggests it’s not a cause-and-effect relationship.

In 2014 Steven H. Hendriks and his team decided to look at the issue afresh and attempt to weed out confounders—other conditions that confuse data sets in clinical research. What they found was that while type 2 was more frequently diagnosed in CTS sufferers, it couldn’t be singled out as an independent risk factor after they adjusted for body mass index, gender, and age. In other words, the type 2 population shares the demographic of the CTS population. And, tellingly, they found no association between CTS and the duration of diabetes, the level of glycemic control, or the degree of microvascular complications—all of which you’d expect if diabetes and CTS had a direct relationship. So it just may be that being heavy, old, and female increases the risk of both diabetes and CTS.

Regarding type 1 diabetes, one seminal study – albeit 10 years old -- showed a "lifetime risk of symptomatic carpal tunnel syndrome in people with T1D." Oy!

In a rare case of diabetes being good news for a change, while we have more CTS than other folks, we don’t tend to get its most severe form. That dubious honor goes to people with metabolic syndrome (which can exist either with diabetes or independently of it).

Oh, but add to the bad news the fact that folks who spend a lot of time typing on computers have an occupational risk factor (and of course you know we type 1's are an internet savvy set!)

We found it interesting that in addition to the “keyboarding occupations,” other high-risk occupations for CTS include assembly line work with repetitive wrist motions, construction work with vibrating power tools, and being a concert pianist.


Is Carpal Tunnel Hereditary?

Lots of folks of wonder whether they got CTS or are at higher risk for it if the condition runs in their family. Sorry to say, the answer is yes.

Medical experts say there is definitely a genetic component to CTS, which is especially at play when it hits young people. Other genetic factors that may contribute to developing CTS include abnormalities in certain genes that regulate myelin, a fatty substance that insulates nerve fibers.

So basically, just like with diabetes, if you have a family history of the disorder, you’re more likely to get it.


Carpal Tunnel Anatomy

Sure, "carpal tunnel" sounds like a mountain pass in the Alps. But in fact, it’s a narrow passageway in your wrist between your forearm and hand. And just like some terrestrial tunnels are shared by both roads and rails, the carpal tunnel in your body is shared by both tendons and nerves. In some people, “traffic congestion” in the carpal tunnel can lead to fender-benders that affect the primary nerve to the hand, causing CTS.

Symptoms range from numbness or tingling on the thumb-side of the hand in some people, to horrible, crippling pain in others. The pain can be felt in the hands, wrist, or forearm. It usually strikes the dominant hand first, but in about half of people who suffer CTS, it is bilateral, causing pain on both sides of the body.

And if you think it's just a case of sore wrists, think again. The pain can be surprisingly intense! Our own AmyT, editor of the ‘Mine, has suffered with CTS, and wrote back in 2008: "I never imagined how painful or debilitating it can be. At its worst, I could literally not make toast for my kids in the morning, let alone help them button their sweaters. I could barely hold my blow drier up straight, and was wiped out from being up all night with the pain."


Carpal Tunnel Syndrome Pain

CTS is actually part of the neuropathy family, and is sometimes called an “entrapment neuropathy.” To better understand how a nerve can become entrapped, you need to be able to visualize how the carpal tunnel is built.

If you were to cut your hand off—not that we’re recommending it—and flop it on the table palm up, you’d find that the carpal tunnel is more like a covered aqueduct than a proper tunnel. It’s a “U” shaped trough of small bones. At the base of the trough are the flexor tendons that power your fingers. Along the top of the bundle of tendons runs the median nerve, the pipeline for sensation for the thumb, index finger, “bird” finger, and part of the ring finger. Over the top of the channel runs a band-like strap of ligament called the transverse carpal ligament, which could be described as a small trench with a lot of plumbing running through it.

CTS happens when the tendons at the base of that trench get inflamed. As they swell, they press upwards on the nerve, and the nerve gets pinched—entrapped—between the swelling tendons at the bottom of the shaft and the ligament strap at the top.

Squished nerves transmit pain signals!


Carpal Tunnel Syndrome Causes

At one time it was believed that repetitive motion of the wrists actually caused CTS, but now most experts agree that isn’t the case. Rather, there’s now consensus that CTS is caused by the size of the carpal tunnel exclusively, and is exacerbated by repetitive motion (in much the same way that being obese doesn’t cause diabetes if you are not predisposed, but can trigger it if you are).

Just as tunnels through mountains vary in length and bore, so too, apparently, do carpal tunnels in people, creating a “congenital predisposition.” Sorry Gang, size really does matter. At least for CTS. Basically, people cursed with smaller tunnels are more likely to get CTS, largely due to the fact that the margin for error is so small: It doesn’t take much swelling to pinch off a smaller tunnel. This also might explain why women are three times more likely to get CTS than men. They have smaller wrists, and hence smaller carpal tunnels.

Maybe this means that if you have a small tunnel, work on the assembly line during the day, and play in an amateur piano league at night, you’re really in for it. Meanwhile, as to the connection between diabetes and CTS, who knows? Maybe the genes that cause diabetes also cause small carpal tunnels?


Carpal Tunnel Syndrome Diagnosis

Keep in mind that symptoms for carpal tunnel start gradually, so it's important to see your doctor early if you’re often feeling "pins and needles" or a burning or a loss of sensation in your hands. Do you wake up at night with your hands or thumbs feeling numb, like they've "gone to sleep"?

When you do get examined, your doctor will run some tests, most importantly to make sure that you aren't suffering from peripheral neuropathy. The two conditions can feel similar, but are not the same thing, and require different treatments.

Two clinical tests used to diagnose carpal tunnel syndrome are the Tinel and Phalen maneuvers, which sound really scary but are actually just flexing exercises to check if you experience a tingling sensation in your hands or wrists. In the Tinel test, the doctors taps the inside of your wrist over the median nerve. If you feel tingling, numbness, or a mild "shock" sensation in your hand when tapped on the wrist, you may have carpal tunnel.

The Phalen test has you resting your elbows on a table, and then letting your wrists dangle so your hands are pointing down with your palms pressed together in the prayer position. (This dorky video sums it up nicely.) A positive result is when your fingers tingle or feel numb within a minute.


Carpal Tunnel Syndrome Treatment

Treatments for CTS range from rest, wrist splints, medications, and physical therapy, to surgery.

For most folks, avoiding activities that aggravate the wrist (which, sadly, includes working on the computer), using a wrist splint and taking ibuprofen can help with the pain and keep the pressure off the median nerve until things heal. Sometimes ice packs, physical therapy exercises or corticosteroid injections may also be administered.

If your condition doesn't improve within a few weeks, your doctor may recommended that you see an orthopedic surgeon or a neurologist to talk about surgery.  In fact, CTS surgery is one of the most common surgeries performed in the United States.

What’s involved? Remember that carpal ligament we talked about at the start? The “roof” of the carpal tunnel? In the traditional CTS open release surgery, the ligament is cut to relieve pressure. Basically, the tunnel is routed out to create a larger bore. Any other tissue (such as a tumor) that may be putting pressure on the median nerve can also be removed during surgery.


Carpal Tunnel Syndrome Surgery?

There are actually two methods of carpal tunnel surgery, called open and endoscopic. But be aware: neither is fool-proof. According to experts, both are 95% effective, but nevertheless, each has advantages and disadvantages, mostly related to ongoing discomfort after the surgery.

The less invasive endoscopic version requires a much smaller incision, which reduces pain, recovery time and scarring. But according to this helpful video from the Hand and Wrist Institute, in about 2% of cases, physicians can’t see the tissue properly to do the endoscopic surgery safely, so have to resort to the “open” version.  

Naturally, diabetes also complicates things; many medical sources still state the disclaimer: "Surgery may only provide partial relief when another medical condition, such as rheumatoid arthritis, obesity, or diabetes, is contributing to carpal tunnel syndrome."

Scott King, a type 1 and former editor of Diabetes Health magazine, was also a longtime sufferer with carpal tunnel. He finally made the move to have general arthroscopic wrist surgery a couple of years ago, and after the procedure, he shared with us: "I have only one little hole in both wrists, almost healed now but scars are still sensitive and I can TYPE again with no pain! The worst part after the surgery was that my hands hurt horribly for the first 2 days… but a week later I was flying out on a business trip, and everything was great! I do wish I had the surgery earlier as I still have tingling in my left hand, from permanent damage to the nerve."

Clearly, choosing whether or not to undergo surgery can be a big decision. Check out this guide from WebMD to help you make a decision.


Carpal Tunnel Syndrome Exercises

So what else can you do to prevent CTS? In addition to keeping blood sugars in range (best way to prevent ALL complications!), a good way to offset CTS risk is keeping your wrists straight as much as possible and avoid flexing them unnecessarily (which often happens when we sit in front of our ubiquitous computers for too long).

To help with this, the ‘Mine’s AmyT even had an ergonomics specialist visit her office to check the set-up of her chair height and keyboard. Sounds pretentious, but it actually really helped, she says.

Experts agree that ergonomic positioning can help prevent pinching the nerves in your risk, super-helpful for both prevention and treatment of CTS.

Also, there are some some simple wrist stretch exercises you can do at your desk any time to help prevent carpal tunnel syndrome and keep your hands and arms healthy and loose.  

So, any PWDs out there suffering with carpal tunnel syndrome? We really feel for you!