Disclaimer: IANAD, I've merely had some seven years of experience with insulin-dependent diabetes mellitus and its various treatment regimes.
Basic knowledge of insulin-dependent diabetes mellitus is assumed, as well as knowledge of what an insulin pump is.
Normally, insulin-dependent diabetes mellitus (IDDM) is treated with several injections every day, commonly one injection of long-acting insulin (which remains active in the body for up to 24 hours) and three injections of short-acting insulin before meals.
An insulin pump, however, only utilizes one type of insulin, which is usually a rapid-acting human insulin analog. The pump continuously issues a small dose (the basal dose), which provides for the user's basic insulin needs - additional insulin (bolus doses) is only needed if the user eats carbohydrates.
- Obviously, most diabetics will benefit from using an insulin pump as it reduces the amount of injections from several per day to two or three a week (replacing the infusion catheter).
- Since some diabetics fail to treat themselves properly simply because they are not comfortable taking 3-4 shots daily, an insulin pump might be the only way for them to stay healthy. (This is why these expensive machines are often issued to IDDM patients free of charge in more advanced countries.)
If the pump continues to function properly, there is no risk of ketoacidosis (this potentially dangerous - even fatal - condition can soon develop if there is no insulin in the bloodstream). However, since the action of the insulin analog is very short in duration, any disturbances in the basal dose have to be taken care of quickly. Some reasons why the basal infusion could stop or fail include:
- The pump's reservoir running out of insulin. This is only a problem if it occurs while the user is sleeping or if no insulin is available. Solution: always check you have enough insulin in your pump to last through the night and always carry extra insulin and a spare reservoir.
- The infusion catheter being accidentally detached. In my experience, the glue Minimed uses on their catheters isn't strong enough. Be sure to shave the area where you attach your catheter, if it is hairy.
- The infusion catheter being cut. I used to live with a cat that was crazy about the smell of insulin, always biting the catheter, which was problematic when sleeping. Always carrying a spare infusion set (catheter and applicator needle) is a good idea.
- Running out of batteries. Fortunately, at least my Minimed 507C will continue to function for several days after a low battery warning. One can also manually apply large doses (10-20 international units) but this is only a temporary solution and should not be attempted without sufficient carbohydrates around as it can be dangerous.
- Malfunction. Minimed offers a lifetime warranty - but then again, if your pump really fails, e.g. pumps too much insulin, said lifetime might be running short.
Ketoacidosis is not, in my experience, a significant concern for the insulin pump user, since it is unpleasant and can easily be remedied. Severe hypoglycemia, or low blood sugar, can easily be fatal, however. Fortunately, it is also easy to detect.
While it would, at first glance, seem that the insulin pump poses a grave threat of hypoglycemia, since it continuously pumps insulin into the user, this is not the case. The basal dose is very small, not enough to cause a lapse into hypoglycemia. At the very least, the blood sugar drops very slowly and the time from when first symptoms of hypoglycemia appear to imminent unconsciousness is hours, if not much more. Also, conventional insulin therapy might be significantly more risky, since it often involves taking injections a long time prior to eating; if a meal is delayed, hypoglycemia might be imminent.
- The pump does not have this problem, since insulin can be taken just before eating.
The aforementioned feature is particularly useful with very small children. If a child has been given an injection and then refuses to eat, he or she must somehow be made to eat - force-fed if need be. A very small child may not understand why he or she simply has to eat.
- With an insulin pump, insulin can be issued in small doses, according to how much the child feels like eating.
- Insulin pump therapy is also much simpler for the user. One never has to remember how much insulin one took, and, besides, the pump maintains detailed statistics of bolus doses which can be reviewed and, with proper equipment, analyzed on a computer by a physician. (Combined with a blood sugar meter that has similar functions, this feature is a very powerful therapeutic tool.)
- A significant negative aspect of the insulin pump is, for many people, the fact that you have to carry it around at all times. However, this can also be seen as a good thing, since ..
- You will feel like a cyborg walking around with your external life support system. Eat your heart out, Kevin Warwick.
By analogy: taking insulin shots is like using a dialup internet connection, and an insulin pump is like having ADSL.
Sources include extensive personal experience with the Minimed 507C external insulin pump, the manual of said device and discussions with my doctor.