I’m been trying to understand why type 2 diabetes can cause a diabetic coma, but every answer I get is straight up “type 2 diabetes can cause
2 diabetic coma”. What damage does high blood sugar causes inside the body that can inflict this specific symptom? Does it have anything
to do with related symptoms? (Like the way colera causes diarrhea, leading to dehydration.) Should I be able to infer this information if I knew enough about diabetes?
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Too much acid in the blood builds up that impairs the normal activities of the cells in your body from a lack of the sugar moving from your blood to inside your cells. There are also likely imbalances in the salts of your blood too. This is more common in Type 1 diabetics that don’t produce insulin because their immune system attacked those insulin producing cells in the pancreas.
So the medical condition I think you’re thinking of is DKA: https://en.wikipedia.org/wiki/Diabetic_ketoacidosis?wprov=sfti1#
And the eli5 answer is that because the diabetic person is not able to regulate their blood sugar via insulin, if they do something like eat and eat and eat and don’t take any insulin they end up with a strange problem that leads to numerous other problems.
So they eat, but don’t take any insulin. Blood sugar is high, but they can’t move that sugar into the cells to be used cause there’s no insulin to open that door. So they feel hungry, and eat some more. Still can’t get any energy, but can’t get rid of the sugar. They start peeing a lot as a way of trying to remove some of the excess sugar. Their body starts producing ketones as an alternative fuel source (like the keto diet). Now they’re incredibly thirsty too. Will be seen drinking gallons of sugary drinks, but they can’t use any of that sugar cause they have no insulin. Coma seems rare in this, but is possible.
Type 2 diabetics aren’t so likely to get DKA. They still have insulin, it’s just their body doesn’t respond that well to it anymore. Feel like coma for them is more likely to happen cause they took too much insulin and dropped their blood sugar too fast, resulting in a coma caused by low blood sugar.
Few parts here. First, Insulin is a “key” that allows sugar to enter the cell so the cell can use it. Diabetics don’t make enough insulin or their cells have too complex of a key for the insulin to unlock it and allow sugar in. So the body has sugar floating around, but due to the lack of insulin it can’t be used, so it just keeps building up in the blood.
Second, water follows sugar and salt. Because there’s so much sugar, your kidneys try to get rid of it and pee it out. Because water follows it, that means you pee out too much water which makes you increasingly and dangerously dehydrated.
Third, in some cases as the body thinks that becaus the cells aren’t getting enough sugar, that it’s because it needs sugar/fuel. We know that’s not the case, it has the sugar/fuel but it just can’t get in the cells. The body doesn’t know that. It starts breaking down fats to use as fuel. The byproduct of this is ketones, which are acidic. The body doesn’t like it’s pH level being thrown off but will do it in emergencies like now where it doesn’t have enough sugar (again, we know it does, the body doesn’t). This throws everything out of wack.
Depending on the type of diabetes and a bunch of factors leads to which problem occurs (diabetic ketoacidosis in the third). The big problem is dehydration. So when these patients show up, we worry mostly about keeping them hydrated and making sure they have enough water in their system.
Insulin resistance means sugar doesn’t go into cells. No sugar in brain cells and your brain doesn’t work anymore. If your brain doesn’t work, coma.
That blood sugar should be going into cells, and those cells are making stuff (insulin) to try to get it inside, but it’s not working. It’s high because it can’t get where it’s supposed to be.
That’s the ELI5 answer, there’s other stuff that builds on that.
The ELI5 answer for type 2 diabetics is extremely high blood sugar levels cause severe dehydration and electrolyte imbalances. The other kinds of diabetic coma are mostly seen in type 1 rather than type 2 diabetics.
Side note, the term “diabetic coma” isn’t really used in the medical world anymore, it’s mostly just a colloquial expression. Way back in the day it was used when we couldn’t rapidly check a blood glucose level or other blood tests that would tell us the exact cause. Now it’s almost trivial to do so
There are two medical emergencies associated with high blood sugar in diabetes:
DKA, which is much more common in type 1 diabetics where the problem is that you don’t make insulin. In this case the lack of insulin makes it hard for your cells to work and leads to a build up of acid which affects your ability of your cells to work. As your acid levels build up, you become encephalopathic or “comatose”. This is treated with lots of fluids and insulin along with very close monitoring.
HHS, which is more common in type 2 diabetics and has a higher mortality rate than DKA. This is more common in older patients who get high blood sugars from type 2 diabetes which causes them to become very dehydrated. In these patients they often are not able to drink fluids to keep up with their dehydration and have severe fluid losses and electrolyte imbalances. These patients can even get swelling in their brain as a consequence of these fluid changes which can lead to coma.
People with diabetes can’t make insulin. Insulin is what lets your body turn food into energy. When your body can’t turn food into energy it turns your body fat into energy instead. When your body turns fat into energy it makes your blood acidic. Acidic blood makes your brain shut down which puts you in a coma.
This is a simplification but the basic concepts are true.