Diabetes Forecast

The “Brittle Diabetes” Debate

Are big swings in blood glucose a condition or the result of improper treatment?

By Erika Gebel Berg, PhD , , , ,


If the pancreas can make a little bit of insulin, it serves as a buffer” against dramatic blood glucose changes.
—Gary Scheiner, MS, CDE

No one likes to be thought of as easily broken, yet “brittle” is sometimes used to describe a type of diabetes that’s characterized by large and sudden swings in blood glucose levels. Attempts to define brittle diabetes, or even verify its existence, have perhaps fallen short. Some experts still believe in brittle diabetes as a distinct condition, while others conclude it’s no more than a myth.

Then and Now

The concept of brittle diabetes was first introduced in the 1940s to categorize people with type 1 diabetes who didn’t seem to respond well to insulin treatment. In the mid-20th century, before personal blood glucose meters became available, blood glucose measurements were hard to come by, so the defining features of brittle diabetes were unexpected episodes of low blood glucose (hypoglycemia) as well as recurrent diabetic ketoacidosis (DKA), a severe complication of very high blood glucose.

 Today, people have a much more detailed picture of how blood glucose changes over the course of a day, thanks to blood glucose meters and continuous glucose monitors. Because blood glucose fluctuations now are easier to track, people may be amazed at just how frequently levels vary. Nowadays, brittle diabetes “refers to glucose variability and the extent to which a person experiences an unexplained variation in blood sugar,” says Gary Scheiner, MS, CDE, owner and clinical director of Integrated Diabetes Services.

Scheiner does not like the term brittle diabetes. He thinks doctors may have coined it when they “threw their hands up” in frustration over cases of diabetes that seemed impossible to treat. He prefers to simply refer to the phenomenon as variability. Everyone with diabetes experiences some fluctuation in blood glucose levels, which raises the question: Does brittle diabetes exist, or is variation just a part of having type 1 diabetes?

Rare Bird

One thing is clear: As the tools for controlling blood glucose have improved, the number of people with so-called brittle diabetes has fallen. Freddy Eliaschewitz, MD, of the Albert Einstein Hospital in São Paulo, Brazil, looked for cases of brittle diabetes in a recent study. Of 500 people with type 1 diabetes who were screened, only 10 met Eliaschewitz’s definition of brittle diabetes—glucose fluctuation so severe that a person cannot have a normal life. “It’s rare and becoming increasingly rare,” says Eliaschewitz, with improvements in treatment, such as insulin pumps.

Even those few who meet the criteria for brittle diabetes may just lack proper treatment, Eliaschewitz says: “Someone with many oscillations may just not be using the right insulin and the right mode of delivery.” If so, brittle diabetes may be overdiagnosed. While perfect control may not be possible, he says, most people with type 1 can, with finely tuned treatment, reduce wild fluctuations in blood glucose.

Mind and Body

Researchers have come up with various explanations, both mental and physical, to explain why some people have more variation in blood glucose than others. “The major causes are psychological,” says Eliaschewitz. For example, he points to people who struggle with anorexia and intentionally skip insulin doses in an attempt to block the absorption of calories. People who don’t take medication as prescribed, perhaps because of psychological issues, may be more likely to experience unexpected fluctuations.

On the physical side, gastroparesis, a diabetic complication associated with nerve damage, affects the speed and consistency of digestion. People with this condition may have problems synchronizing insulin dosing with the glucose absorption from the food they eat, resulting in blood glucose fluctuations. Imbalances in hormones, such as glucagon, can also influence blood glucose variability, says Eliaschewitz.

The ability to make insulin may be what separates brittle from regular diabetes, according to Scheiner. People with type 1 diabetes are unable to produce enough insulin to control blood glucose levels, but recent research suggests that most of them can still make some insulin. And those insulin producers tend to have fewer glucose fluctuations than those who don’t make any insulin. “If the pancreas can make a little bit of insulin, it serves as a buffer” against dramatic blood glucose changes, says Scheiner.

Flattening Out

Smoothing out the dips and surges of blood glucose depends on identifying the cause of the fluctuations. If psychological issues are behind brittleness, treatment with medication or counseling may help iron out things. With gastroparesis, eating small meals and limiting or avoiding certain foods, along with using medications and gastric pacing devices, can improve the consistency of digestion. Undiagnosed or uncontrolled celiac disease (an intolerance to gluten) can result in varied absorption of carbohydrate and unexplained blood sugar swings.

In severe cases of brittle diabetes, some doctors are looking into treatment with islet-cell transplants. This involves transplanting clusters of insulin-making islet cells from a deceased donor into a person with brittle diabetes. Transplants have definite drawbacks, says Eliaschewitz, such as the need to take antirejection medications, but they may be a good option for people who can’t lead normal lives because of blood glucose swings. While islet transplants can greatly improve some people’s quality of life, the results can be temporary. Islet transplants are still an experimental diabetes treatment in the United States, and researchers continue to develop the approach. Whole pancreas transplants are sometimes used to treat brittle diabetes, but surgical risks, possible failure of the organ, and the need for antirejection drugs are considerations. People who have received or need kidney transplants may be good candidates for pancreas transplants. They already take or will need antirejection medications.

Whether you call it brittle diabetes or just variability, there are options for people who have a hard time getting blood glucose to level out. After identifying what’s causing the fluctuations, doctor and patient can come up with an individualized treatment plan to smooth out the ups and downs as much as possible.



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