system
Given the following post, respond as if you're commenting on Reddit:
human
Why do urinary tract infections sometimes cause psychosis in the elderly?
gpt
A Bacteria causing a urinary tract infection can tract up through the bladder and up the ureter and to the kidneys. This infection is called pyelonephritis. Two things can happen: sepsis and kidney failure. Sepsis is when this bacteria gets into the blood and the toxins produced by the bacteria allow fluids to leak out of blood vessels causing extremely low blood pressures and altered mental status, fever, and ultimately death without intervention quickly. The other possibility is kidney failure. The kidney filters BUN (Blood urea nitrogen). When BUN can't be filtered out these toxins can build up and cause altered mental status as well. BUN/Creatinine ratio (a blood test calculation derived from looking at amounts of nitrogen and creatinine in the blood) can be used to test a kidney's filter function.

Hope this helps, Im a 3rd year medical student in the US.