Carpal Tunnel Syndrome and Diabetes

Carpal tunnel syndrome is a relatively common neurological problem in which the median nerve is compressed in the wrist.

The classical symptoms are:

• Tingling, numbness or burning in the fingers or hand, especially thumb, index, middle or ring fingers, but not your little finger. It is most typically present on waking, but can occur after using the hands. Some people "shake out" their hands to relieve their symptoms.
• Pain radiating or extending from the wrist up the arm to the shoulder or down into you’re the palm or fingers, especially after forceful or repetitive use.
• A sense of weakness in the hands and sometimes a tendency to drop things
• Numbness, especially in the tips of the thumb, index, middle and ring fingers.
• Eventually the small muscles that control the thumb, index and middle fingers can weaken and atrophy.

In many people there is not obvious cause, although it is more common in women approaching menopause, and these days it can be one of the problems associated with using a computer mouse of keyboard for long periods. Every student of health care learns that there is a great long list of causes including:

• Pregnancy
• Rheumatoid arthritis
• Trauma
• Hypothyroidism
• Diabetes
• Amyloidosis
• Acromegaly
• Myeloma
• Tumors

Although I was taught about carpal tunnel syndrome not just as a cause but also as a predictor of diabetes more than 30 years ago, it has been forgotten by some non-specialists.

There is some new research from King’s College in London that has suggested that carpal tunnel syndrome may be a harbinger of diabetes.

As many as 20% of people with diabetes have a compression neuropathy such as carpal tunnel syndrome, and in people with limited joint mobility – a complication of diabetes - the incidence may be as high as 75%. The new research indicates that carpal tunnel syndrome may precede the diagnosis of diabetes by up to 10 years. The work was based on an analysis of 2,655 people who were diagnosed with type 2 diabetes in 2003-2004. The researchers excluded people with other known risk factors for carpal tunnel syndrome. The relative risk for subsequently developing diabetes was 1.63.

This research shows once again that diabetes can sometimes make its presence felt years before it has been formally diagnosed. A study published in 2003 found that 56% of people with peripheral neuropathy of unknown cause actually had abnormal glucose tolerance tests.

Earlier this year, researchers form the Netherlands did a retrospective review of 516 people with carpal tunnel syndrome, and found only two people with diabetes. They therefore recommended that routine screening for diabetes was not worthwhile in otherwise typical carpal tunnel syndrome.

I disagree with them.

I think that it would be wise to screen people with carpal tunnel syndrome for any disturbances of glucose metabolism, including insulin resistance, and if they are at a particularly high risk of developing diabetes, it would be worth going ahead and doing a glucose tolerance test. We don’t often do them these days, but this would be one of those times.

Comments

[Richard Petty]

I had a nice letter following this post:
Hi - FYI, I was diagnosed with fibro 3 years ago, and my symptoms (among them carpal tunnel / myofascial pain in my forearms and hands), were greatly relieved by following a low-GI diet. Since then, I've always though of fibro as "McDiabetes." Following the low-GI diet helped when nothing else would, however, it only brought me back to about 65%. It was when I started taking pancrease enzymes with every meal that I felt almost like my old self. There is a family history of "type 1.5" diabetes (LADA), so I'm a little concerned that the fibro diagnosis was incorrect. I was wondering if you could direct me to articles on how to distinguish peripheral neuropathy pain from fibromyalgia pain. I'm not a medical professional."

This really does confirm what I said in the post and re-affirms the importance of metabolic control: if the metabolic derangements can be controlled, many of the complications should be relieved.

In addition, some people find that many types of painful symptoms may be worsened by certain foods.

Fibromyalgia and neuopathy are usually extremely easy to differentiate on clinical grounds. I can't say which you have without a full history and examination, but I can make some general observations.

The distribution and character of the pain in the two conditions is quite different. Neuropathy almost invariably starts at the ends of the longest nerves in the body, so usually in the feet and hands, in what is known as a "glove and stocking" distribution. It may slowly inch its way closer to the center of the body. There is usually numbness first and then the tingling and burning starts. Neuopathy is only very rarely associated with tenderness in MUSCLES, which is the hallmark of fibromyalgia.

If that does not give you the information that you need, please let me know and I shall write some more about differentiating the two.

Kind regards,

RP

[Caitlin]

Thanks! Helps a lot. - C