Step I salicylates

[workhardplayhar]

Unless I have gone completely nutty (a possibility) salicylates are aspirin right? I am confused because FA says that they cause a normochloremic metabolic acidosis but Kaplan says that they cause a resp alkalosis (in high dose) and a respiratory acidosis (in toxic dose). So what am I missing?

 

[jfotos]

Actually, as far as I know all of those are true.

Normochloremic Met. Acidosis - b/c you are dumping a bunch of salicylic acid into your blood (the S in MUDPILES)

Resp. Alkalosis (high does) - Salicylates also function to stimulate the respiratory centers so that resp. rate increases.

Resp. Acidosis (toxic dose) - My guess is that the incredible amount of acid and trauma to the system at that point starts to effect basic physiological functioning and the patient starts to fall into resp. depression.

 

[workhardplayhar]

I though the resp alkalosis was due to uncoupling of oxidative phosphorylation but i do think the resp acidosis is due to inhibition of resp centers.

 

[jfotos]

Salicylates do uncouple the ox. phos. system, thats a good point, which causes mainly increased heat production and increased speed of the ETC leading to increased O2 utilization (and thus even more CO2 as more NADH is needed).

From eMedicine:
"Salicylates directly stimulate respiratory centers in the medulla, causing hyperventilation and, subsequently, respiratory alkalosis."
I think they mean for high dose, and the inhibition may be only for toxic doses.

If only one of the answers was - "Patient gets all kinds of messed up"