Ammonia levels: how high is "too high"?

[closertofine]

I can't seem to find this info anywhere...I have the reference range our lab uses (the top of the range is 0.8, not sure of the units), and we had a patient with a level of 1.3. But my resident thought maybe that wasn't crazily high, though neither of us was sure (we're on psych)...and from what I've read so far online, any bit of excess ammonia is apparently too much!

But the LFTs came back normal...so I'm a little stumped. Anyone know if this would be considered significant? If so, I'm trying to figure out what diseases would cause just elevated ammonia...and also semi-acute psychosis. Maybe the two are related?! I'm trying Pubmed right now. Very interesting case.

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[Mr. McDuck]

I don't have any good answers for you, but I'd love it if you'd keep us updated on the situation via this thread as you go along.

 

[closertofine]

I don't have any good answers for you, but I'd love it if you'd keep us updated on the situation via this thread as you go along.

Yeah...I don't want to violate the patient's privacy, so I hope what I've posted already is OK in terms of that...but I can let you know if we end up thinking the ammonia is at all relevant. I don't think it's been a big concern so far, but at this point we're kind of grasping at straws before settling on a psychiatric diagnosis (she has some symptoms that would be unusual for schizophrenia, etc)...

 

[jojo14]

Yeah...I don't want to violate the patient's privacy, so I hope what I've posted already is OK in terms of that...but I can let you know if we end up thinking the ammonia is at all relevant. I don't think it's been a big concern so far, but at this point we're kind of grasping at straws before settling on a psychiatric diagnosis (she has some symptoms that would be unusual for schizophrenia, etc)...

My only experience with high ammonia levels has been in patients with hepatic encephalopathy. Their levels were always been higher than 1.3- I think the lowest I saw was 20-something and the highest I've seen was around 600 in my year on the wards. The caveat though is that the level does not correlate to severity of the illness. The patients that I am speaking of were frequent fliers and we knew their "baseline" ammonia levels if you will-some patients were fully functioning at 20 once they came down from 70, and some didn't know their name when their level was 20.

I hope this helps- don't think your patient has this dx however. If so, she is in the wrong place. I don't know of any disease states where it is minimally elevated.

 

[Mr. McDuck]

As far as privacy goes, as long as you just talk about the values and the basics of the case without giving identifying features of the patient, you're okay. We do this all the time for case reports, etc.

I was going to post that 1.3 doesn't seem at all very high, but I wasn't entirely sure; thanks for clearning that up jojo.

 

[tr]

From what I understand, the actual value of the ammonia is almost meaningless, because there is little to no correlation between the ammonia level and clinical manifestations of uremia.

Basically it's better to use it as one piece of information in a constellation. E.g., if the patient is disoriented and his LFTs are screwed up and the ammonia level is 200, then you might have a problem.

Based on the above, here's my two-bit opinion: what you've got there, I wouldn't worry about.

 

[closertofine]

OK, thanks, you all...I didn't realize the levels could get up in the range of 20 or 70 or higher...so 1.3 doesn't sound so bad now! Thanks for clearing it up.

 

[closertofine]

OK, if you could humor me again...does anyone know if there's a website, etc where you can find this kind of information? Because now I'm wondering about a lymphocyte count in the WBC differential (in the same patient) that is low...and wondering if HIV is a possibility...but once again, not sure how low is "too low"? The normal range given was 30-40, and the patient's was 15...sounds like a problem to me...but I really don't know. Med consult?!

 

[werd]

from what i've been told the actual level of ammonia isn't that correlated with symptoms... liver failure patients can be fine at 100 if their body is used to it, or you can be encephalopathic at 70. we had a liver patient and we didn't even track the ammonia, just the mental status and neuro findings. you can look at ammonia to identify a liver problem but it's hard to tell when it's going to start affecting someone.

 

[kam730]

OK, if you could humor me again...does anyone know if there's a website, etc where you can find this kind of information? Because now I'm wondering about a lymphocyte count in the WBC differential (in the same patient) that is low...and wondering if HIV is a possibility...but once again, not sure how low is "too low"? The normal range given was 30-40, and the patient's was 15...sounds like a problem to me...but I really don't know. Med consult?!

uptodate and emedicine are my go-to websites, both are very helpful. try them.

 

[closertofine]

uptodate and emedicine are my go-to websites, both are very helpful. try them.

thanks, those have helped me in the past too...I'll check them out. I think I've gotten these current things figured out though...feel a little stupid for asking now! 😛

 

[chameleonknight]

Just a quick note, we got a lecture the other day about how low T-cell counts do not an HIV infection make. If you're concerned about HIV, don't bother trying to infer it from a lymphocyte count...just get an HIV test.