Braille Monitor                                             April 2016

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An Introduction to Diabetes and Insulin Pumps

by Mike Freeman

From the Editor: One pledge we have made is to use the pages of the Braille Monitor to keep people up-to-date on one of the most significant health issues affecting the blind—diabetes. Mike Freeman is the president of the Diabetes Action Network, and he does a stellar job of scanning the literature and bringing information to the division and this magazine. Sometimes what he offers are articles synthesizing what he has learned. At other times he recommends that something he has read be reprinted. This time he has done both because of the complexity of the subject being discussed and his attempt to explain alternative ways to treat diabetes, the role of technology, and the barriers to blind people wishing to use it. Here is what he says:

Mike FreemanDiabetes mellitus (the full medical term for the disease we usually call diabetes) is a metabolic disease characterized by an insufficiency in the production of the hormone insulin or the inability of the cells of the body to efficiently use this hormone. Insulin is normally produced by the pancreas, a small gland located behind the stomach. When we eat, our digestive system breaks down the food into its components—protein, fat, carbohydrate, and trace minerals. The water-soluble carbohydrate is in turn broken down into its components, principally the simple sugar known as glucose. The cells of the body then take in this glucose to meet their energy needs. The protein and fat are also broken down and sometimes also are converted into glucose for energy. The glucose that isn't needed for current energy is stored in the liver as what is known as glycogen; the liver may be ordered later to release this glycogen if the body detects that the level of glucose in the blood is getting too low. The water-insoluble carbohydrate is called fiber, and the body gets rid of it as waste.

All of the cells of the body need insulin in order to process glucose with the exception of brain cells that can use glucose directly. Thus, if there is no insulin being produced by the pancreas (Type 1 Diabetes) or there is less insulin being produced than is needed or the cells of the body don't respond to insulin very well (both conditions are called Type 2 Diabetes), the cells can't get enough energy, and the level of glucose in the blood rises to dangerous levels. Over time, high levels of glucose in the blood often lead to damage to other systems in the body, resulting in such complications of diabetes such as heart disease, arterial disease, diabetic retinopathy (damage to the nerves in the eyes), and diabetic peripheral neuropathy (damage to nerves of the hands, feet, and possibly nerves controlling other functions such as digestion). Thus, diabetic complications are serious and are to be avoided if possible. The way to do this is to control the level of glucose in the blood, keeping it as close to the normal level for people who do not have diabetes as possible while avoiding the side effect of blood glucose getting too low.

For people with Type 1 diabetes, this means supplying insulin artificially to replace that no longer being produced by the pancreas. This may also be the treatment of choice for people with Type 2 diabetes. Some people with Type 2 diabetes are able to control the disease through diet and exercise alone (exercise makes muscle cells take up blood glucose for energy). In addition, there are a number of drugs available that do things like getting the pancreas to produce more insulin, lessening the amount of carbohydrate being absorbed into the body, lengthening the amount of time it takes carbohydrates to be absorbed so that the level of blood glucose in the blood rises more slowly than might be expected, and, finally, making the cells use insulin more efficiently (we call this last phenomenon "lowering of insulin resistance"). All these medications can be administered by mouth except for insulin; the digestive system would destroy the insulin, so it must be injected under the skin. People with diabetes can inject themselves directly by shots or by using insulin pumps. In either case, these people with diabetes must balance the amount of carbohydrate they eat with the amount of insulin they inject to process this carbohydrate.

From the foregoing it should be clear that diabetes is not one of those diseases about which the doctor says: "Take these pills and come back in two weeks to see if you're well again." Diabetes involves a fair amount of effort from the person with the disease; blood glucose levels need to be checked from once a day to as often as ten or twelve times a day, depending upon the person; meals must be planned so that the amount of nutrients they contain are known or the amount of these nutrients must be guessed at and medications must often be taken in order to deal with these nutrients. Between finger sticks, giving oneself shots, and learning all the terminology to begin to understand and manage the disease is a challenge to say the least.

There are two blood glucose meters fully accessible to the blind: the Prodigy Voice® and the Solus V2® (only the last ten readings from memory can be reviewed using the meter alone with speech, although all the readings are available on the visual display). Insulin stored in "insulin pens" is easily controlled since pens click for each half-unit or full unit of insulin one desires to inject (100 units equals one cubic centimeter or one milliliter). There is also a device known as the Prodigy Count-a-Dose, which allows insulin dose amounts to be selected accurately using insulin vials and syringes.

Now we come to insulin pumps, discussed in the article that follows. These are microprocessor-controlled machines which inject insulin under the skin using cannula and tubing or, in one instance, a small reservoir taped to the skin with a small tube sticking into the skin. The insulin dose administered by the pump is controlled by the program running in the machine's microprocessor or by the person wearing the pump. Insulin pumps are all the rage among diabetic endocrinologists today because they have the potential to give better control over the amount of insulin in the body, thus potentially allowing the pump-user to more closely approximate the way the pancreas would normally secrete insulin into the body during the day and night. Insulin pumps can also be beneficial for those squeamish about injecting themselves using needles (although needles are disposable, much smaller, sharper, and thus, less painful than in the past). The kicker is that the insulin pump requires the person to know more about diabetes and pay more attention to control than might be the case were a pump not used. Depending upon the person, injections might be preferable since the person is not attached constantly to a machine. It's very much a case of "different strokes for different folks."

The article below also discusses “continuous glucose monitoring systems" (CGMS's). These are blood glucose meters that, rather than assaying a sample of blood directly, report the amount of glucose in the blood inferred from a censor placed under the skin and transmitted to the meter wirelessly. The censor is replaced every few days. The meter usually records the glucose reading every five minutes, displaying these readings as a graph or by time and date and setting off an alarm if the readings it sees are below or above thresholds set by the meter user. Finger-sticks are not gone completely, though. The meter and censor's readings must be calibrated using the results of blood glucose readings taken using a conventional blood glucose meter at given intervals, perhaps once every day or two.

Ideally, the CGMS and pump should talk to each other, allowing the pump to infer how much insulin it should give or not give depending upon the CGMS reading it sees. This would, in effect, amount to an artificial pancreas. There are some such systems in clinical trials, but none have been tested and approved by the Food and Drug Administration (FDA) and therefore are not available for purchase. So people with diabetes who use pumps still must control blood glucose levels themselves.
Certain terms used in the article that follows may be unfamiliar:

If this article and the one that follows leaves the reader with questions, please contact Mike Freeman, president of the Diabetes Action Network, by writing to him at <[email protected]>.

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