Question about diabetes mellitus

[NPK]

I know that diabetics often have glucose in their blood but it can't be absorbed into the tissues because of the lack of insulin or lack of insulin receptors..so why do diabetics carry around glucose with them for emergencies? If they haven't got insulin, eating glucose won't do anything...

I'm obviously missing something!

[Glider]

Diabetics carry glucose because hypoglycaemic episodes are much more common than hyperglycaemic episodes. The reason for this is that whilst people with diabetes rarely forget to take their insulin, they do sometimes forget to eat enough for the insulin they have taken, so they carry around a 'top up' to be safe.

[timo]

Also, a hypoglycaemy (lack of glucose) is much more dangerous (you can fall unconcious which alone is a life threatening state) than a hyperglycaemy (excess of gloucose; you get nervous, the veins are damaged in the long run).

[jdurg]

As a Type 1 (Insulin Dependent) Diabetic, I agree with what has already been posted above. In a normal human being, the liver and the pancreas work in conjunction to make sure that the level of sugar in the blood remains at a constant 85-120 mg/dL. (I'm not sure on the exact range for a 'normal' person, but that's the range I try and achieve). When you eat, it triggers the islet cells in your pancreas to generate insulin so that the body can absorb the sugar into the cells and metabolize it. The thing is, the islet cells don't exactly 'stop' when they are supposed to, so your liver also breaks down glycogen into glucose in order to cover any excess insulin that is produced by your pancreas.

 

Now in a diabetic, things are a bit different. For Type 2 diabetics, their pancreas produces insulin, but it's either not enough or their cells simply can't make use of it. This causes their blood sugar levels to rise. (Hyperglycemia). For Type 1 diabetics (myself), an autoimmune reaction causes their body to destroy all of the insulin producing cells in their pancreas, so they don't have any way to produce insulin on their own. Because of this, they have to take injections of insulin in order to to control their blood sugar levels.

 

Hypoglycemia (Low levels of blood sugar) is a short term danger while Hyperglycemia (High blood sugar) is an insidious long term danger. Blood with a lot of sugar in it is thicker than normal blood. As a result, your heart needs to pump a bit harder and delicate tissues in the kidneys and eyes begin to get damaged by this 'thicker' blood. Tiny blood vessels and nerves in your extremities can get damaged by this high level of sugar causing you to lose feeling and circulation in your feet in particular. Wounds will heal slower, and over time your vision will get worse and worse as blood vessels in your retina begin to rupture and your retina dies causing you to go blind.

 

The brain needs sugar in order to function, and if there is not enough sugar in your blood it's exactly like being intoxicated on alcohol. Your judgement is the first thing that goes, followed by your ability to do things like stand up, focus, walk, speak, type, etc. Pretty soon, if you don't get enough sugar in your blood, you will go unconcious and unless your liver is able to cover that extra insulin in your blood, brain tissue will begin to die.

 

Now back to the liver. As I stated earlier, the liver naturally breaks down glycogen into glucose in order to give your body a constant supply of sugar. This sugar allows you to function. If it weren't for this constant glycogen break down, you'd only have energy to function when you were infusing sugar into your system. This is part of the feedback mechanism which results in you craving sugar after you've eaten some. When you eat sugar, you get the rush as your pancreas starts producing insulin so that you can metabolize the glucose. Because of this high influx of glucose, your liver cuts back on the glucose production while your pancreas continues to make insulin. So shortly after taking in a bunch of sugar and metabolizing it, there's a little catch-up period where your liver isn't making enough sugar to cover the insulin in your system. As a result, you crave sugar and want to get more of it as you have a temporary period of a low blood sugar.

 

For a diabetic, the fact that their liver is constantly producing glucose but they don't have enough or can't make use of their insulin causes a problem. The background glucose production will build up and create a high blood sugar. Therefore, diabetics usually inject a long-acting insulin which will cover the background glucose production of the liver. The insulin doesn't cover the sugar increased caused by eating a meal, but it does handle that background sugar production to keep the blood sugar in check. The thing is, sometimes we do things like do a lot of excercise which causes our liver to slow down or stop glucose production for a while. Meanwhile, the background insulin in our system is lowering our blood sugar. As a result, there can be a case where there's too much insulin and not enough sugar in the blood. This is why we carry glucose tablets with us. It allows us to quickly get glucose into our system and make up for what the liver doesn't naturally produce. There may also be the case where we give ourselves too much short acting insulin and cause our blood sugar to drop too low. Again, we take the sugar to cover this.

 

For diabetics, drinking alcohol is a very dangerous thing to do and they must monitor their blood sugar like crazy if they drink. When you drink, the liver immediately starts converting the ethanol into something else as it metabolizes it. The primary function of the liver is to detoxify you. Glucose production comes second. So if your liver is taxed by metabolizing the alcohol, it won't be producing glucose, and it won't do so for quite some time. So while a diabetic drinks, their blood sugar may increase tremendously from all of the carbohydrates and sugars in a lot of drinks. As a result, the diabetic may give an insulin injection to counteract the hyperglycemia. The problem is, because the liver is so busy detoxifying the person, it won't be able to make enough sugar to cover the background insulin as well. So a few hours later, the background insulin is busy working, parts of the short term insulin are busy working, but the liver is too busy cleaning the person up. As a result the blood sugar drops precipitously and the drunken diabetic, who may be passed out or asleep at this point, could have a fatally low blood sugar. A diabetic who drinks MUST watch what they take in while drinking and make sure that their blood sugar is a little bit high when they go to bed for the night. There have been nights where I've been out drinking and when I come home my blood sugar is about 385 mg/dL. When I wake up the next morning, it has dropped to 81 mg/dL. If I had given myself a shot before going to bed, I could die in the middle of the night.