What is a common consequence of untreated dehydration in terms of kidney function?

Untreated dehydration leads to a decreased blood volume and an increase in blood osmolarity. In response, the kidneys conserve water, producing less urine to maintain hydration. This scenario causes the glomerular filtration rate (GFR) to decrease because the kidneys prioritize conserving fluids over filtering blood. When there's reduced fluid available for filtration, the kidneys may not be able to adequately perform their function, which can impair overall kidney health.

In contrast, increased urine output would typically be associated with conditions that lead to overhydration or specific types of diabetes, which is not the case with dehydration. Elevated blood sugar levels are unrelated to the immediate consequences of dehydration on kidney function. Lastly, while hydration is important for kidney health, untreated dehydration generally does not lead to improvements in kidney function, as it can instead exacerbate existing kidney issues or lead to acute kidney injury.