clarification on salicylate poison please!!

[harv1212]

would appreciate people's take on this ... I can't find any definitive source

Immediate Salcilyate poison (0min-1hr):
Respiratory Alkalosis, pH basic (>7.4), no HCO3- compensation

Time elapsed since salicylate poisoning (3hrs or more)
Respiratory Alkalosis, Metabolic Acidosis, pH acidic (<7.4), low HCO3-

In gen is that right????????

---

Members don't see this ad.

 

[PokerDoc]

hmm you should probably back up a minute and realize whats happening first, and then it will make more sense to you, because it looks like you're confused to the point that you don't even know what youre asking for help on. Look over the mechanism of action and make sure you understand it, I dont feel like writing it all out when its in first aid.

But the differences you highlighted are due to acute, and then chronic respiratory alkalosis.. metabolic compensation doesnt begin immediately. you might want to review that topic in general as well.. again, outlined real well in FA (and even better in goljan, CH 3 i think).

 

[harv1212]

ummm ... actually i'm not that confused and the acid/base questions are usually not hard for me .... thanks for the attitude though ......

Salicylate poisoning is not a normal acid/base compensation question. If it was the immediate effect of adding an acid to your system would be an acidic pH with a respiratory compensation ... but in salicylate poisoning it's immediate effect is on the resp center in the brain causing a primary problem of resp alkalosis which you would expect to over time compensate with a metabolic acidosis ... but with the pH still basic. From my understanding the time after the salicylate poisoning the pH goes acidic because of the actual metabolites of salicylic acid ....

I'm just asking if that's right. And it's not in FA (the normal acid/base comp stuff is). And I don't own goljan's book.

 

[PokerDoc]

. And I don't own goljan's book.

well I was just trying to help and you clearly have a short fuse so I'm done here... but i couldnt help but laugh at this comment after complaining you couldn't find a definitive source.

 

[Vikingwizardguy]

so testy in here...

off of merck's own website: "
Pathophysiology
Salicylates impair cellular respiration by uncoupling oxidative phosphorylation. They stimulate respiratory centers in the medulla, causing primary respiratory alkalosis, which is often unrecognized in young children. Salicylates simultaneously and independently cause primary metabolic acidosis. Eventually, as salicylates disappear from the blood, enter the cells, and poison mitochondria, metabolic acidosis becomes the primary acid-base abnormality."


so it seems as if you'll get a simultaneous respiratory alkalosis (due to respiratory depression) and metabolic acidosis (prob increased anion gap, remember, it's salicylic ACID). Not sure which predominates but with the neuro symptoms I'm guessing it's the alkalosis. After a while though it seems that on top of your salicylate you're getting a lactic acidosis and you might end up with an overbearing metabolic acidosis. In theory, the acute pH might be very close to normal with the two effects countering each other.


thoughts?

 

[username456789]

so testy in here...

off of merck's own website: "
Pathophysiology
Salicylates impair cellular respiration by uncoupling oxidative phosphorylation. They stimulate respiratory centers in the medulla, causing primary respiratory alkalosis, which is often unrecognized in young children. Salicylates simultaneously and independently cause primary metabolic acidosis. Eventually, as salicylates disappear from the blood, enter the cells, and poison mitochondria, metabolic acidosis becomes the primary acid-base abnormality."


so it seems as if you'll get a simultaneous respiratory alkalosis (due to respiratory depression) and metabolic acidosis (prob increased anion gap, remember, it's salicylic ACID). Not sure which predominates but with the neuro symptoms I'm guessing it's the alkalosis. After a while though it seems that on top of your salicylate you're getting a lactic acidosis and you might end up with an overbearing metabolic acidosis. In theory, the acute pH might be very close to normal with the two effects countering each other.


thoughts?

This is essentially it. For testing purposes, respiratory alkalosis definitely occurs first, but if you ingested the stuff several hours ago, your pH will likely fall in the normal range due to the delayed metabolic acidosis.

Remember that, by definition, a single derangement will really never fully compensate to bring the pH to normal. If a patient has jacked bicarbonate and CO2 and a normal pH, you've got a mixed disorder. And no matter what the pH, if the anion gap is elevated, you have a metabolic acidosis somewhere.

 

[knuckles]

um...wouldn't respiratory depression cause respiratory acidosis? I thought the salicylate poisoning caused hyperventilation by stimulating respiratory centers.

 

[Vikingwizardguy]

um...wouldn't respiratory depression cause respiratory acidosis? I thought the salicylate poisoning caused hyperventilation by stimulating respiratory centers.

sorry error on my part. Ya there's stimulation leading to the alkalosis.

 

[username456789]

um...wouldn't respiratory depression cause respiratory acidosis? I thought the salicylate poisoning caused hyperventilation by stimulating respiratory centers.

Stupid error #2 on my part tonight (agreeing with it all) by glossing over things. But everything else he said was good.

 

[PokerDoc]

um...wouldn't respiratory depression cause respiratory acidosis? I thought the salicylate poisoning caused hyperventilation by stimulating respiratory centers.

yup, just like its written in FA.. and they even have it in a flow chart showing both scenarios lol

 

[harv1212]

care to share the page # in FA that shows this??? I have searched and cannot find it in FA

Also, managed to get my hands on goljan's ... he says that it will cause a basic pH (7.42) .... USMLE world said that if it's a few hours after the initial acute poisoning then the pH will be acidic (pH was around 7.2). is goljan just referring to the initial acute poisoning that stimulates the respiratory center?

 

[PokerDoc]

hey harv, check out UW question ID 1544

beautiful explanation on every aspect of this.. should be all you need.. I just came across the question.