# UTI and AMS



## Simusid (Mar 3, 2012)

As a new basic, I learned pretty quickly that a UTI can cause altered mental status in the elderly.   I know it's a very common sign.   The thing I don't understand and would like to learn is exactly why a UTI would cause AMS.   What's the physiology behind it?   What's different in the elderly as compared to twenty-something college girls?  I'm not picking on them but I knew a ton of girls in college that got UTIs and never had AMS as a sign [insert obvious joke "how would you know?"]

I've tried to google but got overwhelmed with statements about the relationship but not the explanation.   No clear answer from my medic friends either.   So to redundantly repeat myself... WHY does a UTI cause AMS in the elderly?


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## Veneficus (Mar 3, 2012)

Simusid said:


> As a new basic, I learned pretty quickly that a UTI can cause altered mental status in the elderly.   I know it's a very common sign.   The thing I don't understand and would like to learn is exactly why a UTI would cause AMS.   What's the physiology behind it?   What's different in the elderly as compared to twenty-something college girls?  I'm not picking on them but I knew a ton of girls in college that got UTIs and never had AMS as a sign [insert obvious joke "how would you know?"]
> 
> I've tried to google but got overwhelmed with statements about the relationship but not the explanation.   No clear answer from my medic friends either.   So to redundantly repeat myself... WHY does a UTI cause AMS in the elderly?



This is a complex multisystem pathology.

It involves underlying renal function, liver function, immunological function, vascular and the effects of nitrogen (among other things) on the CNS.

Getting old sucks.

The simplest way to say it (but not the most accurate) is that impaired renal function causes azotemia, which in turn causes mental status changes.


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## Dwindlin (Mar 4, 2012)

Veneficus said:


> This is a complex multisystem pathology.
> 
> It involves underlying renal function, liver function, immunological function, vascular and the effects of nitrogen (among other things) on the CNS.
> 
> ...



Or just plain old urosepsis.


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## Veneficus (Mar 4, 2012)

Dwindlin said:


> Or just plain old urosepsis.



True,

but it affects the same organ systems by overlapping mechanisms


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## Simusid (Mar 4, 2012)

Dwindlin said:


> Or just plain old urosepsis.



Yup, I get that part.   In fact my patient was septic, among other things.  My quest is to understand how that leads to AMS.   I've read about 20 web pages that cover azotemia, that was a very good start (thanks Veneficus).  

I'm lucky enough that if I REALLY get lost, and I'm stubborn enough, I can ask my father in law's neurologist at his next appt.   I'm sure he'd try to walk me through it!


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## Veneficus (Mar 4, 2012)

From sepsis, you are looking at AMS from inadequete delivery of o2.

SO take your pick, toxic insult or ischemia.


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