The Earliest Complication?

I've kept my blood sugar as close to normal as possible for the last eight years, with A1cs almost always in the 5% range. As a result, my eyes and kidneys test out great and I have no neuropathy in my feet except for the nerve damage caused by my ruptured disc (which is distinguished from diabetic neuropathy in that it is only on one side, not symmetrical).

But I have developed one, to me, serious complication which my researches have found few doctors, except for the diabetes expert, Dr. Richard K. Bernstein, recognize as being a diabetic complication.

That complication is tendon damage.

Tendon damage can manifest many different ways. The most frequently detected is carpal tunnel syndrome. This recent study found that people who had been diagnosed with carpal tunnel syndrome were 36% more likely to later be diagnosed with diabetes, regardless of other diabetes risk factors.

One reason for this may be that just slightly higher than normal blood sugars cause tendons to grow abnormally thick. A study that linked tendon thickening to high blood sugars was published in Diabetes Care

Thickness of the Supraspinatus and Biceps Tendons in Diabetic Patients
Mujde Akturk, MD, Selma Karaahmetoglu, MD, Mahmut Kacar, MD and Osman Muftuoglu, MD.

Another diabetes-related form of tendon damage results in frozen shoulder. Frozen shoulder is known to be common among people with diabetes, though it occurs in people who have not been diagnosed with diabetes, too. My guess is that careful examination of post-prandial blood sugars in "non-diabetic" people with frozen shoulders not originating from sports injuries or other known traumatic events might show that the "non-diabetic" people with frozen shoulders have significantly elevated postprandial blood sugars.

Dr. Bernstein describes "piriformis syndrome" as another diabetic-related tendon problem in his article Some Long-Term Sequelae of Poorly Controlled Diabetes that are Frequently Undiagnosed, Misdiagnosed or Mistreated

I myself have yet another constellation of tendon problems that manifests in my feet. It is called "tarsal tunnel syndrome" and is the foot equivalent of carpal tunnel, resulting in painful shooting pains, first when walking up stairs, and later when it worsens, just plain walking.

Why are tendon problems often the Sentinel Complication--the first warning that something is seriously amiss? Because tendons in their normal state don't have much of a blood supply, so anything that compromises the blood supply to muscles, even slightly, will deprive the tendons of the nutrients they need to keep healthy. This mild failure of circulation starts happening even at the "mildly impaired" blood sugar levels most doctors dismiss as "pre-diabetic" and, all too often, ignore. Hence a failing tendon can be the first sign of microvascular problems.

MRIs show that it is possible to have tears in your tendons without any pain or other symptoms. You can read more about one kind of tear related to frozen shoulder HERE.

But if you are unlucky, as I have been, the tears will be in places that impinge on nerves and the pain can limit your mobility (a medical euphemism that translates into "making everything you do hurt like hell so that you mostly want to stay home, curled up in a fetal ball.")

Dr. Bernstein makes the point that just lowering blood sugars will not reverse these tendon problems which take a while to heal, and may respond to time and trigger point therapy, though he suggests normalizing blood sugars may stop new ones from starting.

My own experience has been that my tendon problems have gotten significantly worse after I have made major efforts to lower my blood sugars. My first frozen shoulder occurred after I dropped my A1c to 5.2% from the mid 6% range after diagnosis. Since starting insulin and bringing my fasting blood sugar down to truly normal (for the first time in my life) I've had tendon problems in my foot, my knee, and most painfully, my shoulder ,which is acting like it has a seriously torn rotator cuff.

Why this should be is a mystery, but since other complications initially get worse--or more painful--with improvement of blood sugars, like neuropathy and retinopathy, it is possible that there is some reasonable explanation.

If you've had problems with tendons, I'd love to hear from you about how they resolved and whether better blood sugar control made them better or worse.