system
Given the following post, respond as if you're commenting on Reddit:
human
How does dehydration kill you?

Particularly dehydration from not drinking water. I'm not asking about hypovolemia due to hemorrhage, burns, diarrhoea, vomitting or other factors.   


I'm aware that dehydration disrupts a plethora of biological processes which leads to a variety of things going wrong in our body. But there must be one (or perhaps a few?) factor(s) that eventually lead to death.   
Is it the hypovolemic shock? Is it perhaps dyselectrolytemia?   


I have a vague memory in my mind that it's because of hyponatremia, but that doesn't make much sense. We only lose sodium through our sweat and can replenish it from food, which means if we avoid an environment that causes us to sweat and eat enough, that'll prolongue our chances of surviving without watter. Sounds ridiculous.   


Hypernatremia makes more sense. If we don't drink water, we lose water content while our sodium stays relatively the same (we lose some through sweat, but sweat is quite low in sodium and we would lose more water than sodium anyways). High blood sodium concentrations would obviously dehydrate our cells osmotically as well as disrupt CNS action potentials.
gpt
Dehydration kills you by making you unable to flush out toxins in your urine and feces. 

Eventually your kidneys shut down from severe dehydration and you start to build up toxins which will begin the stages of sepsis. You eventually become poisoned by your own toxins that the body is unable to remove.