Ingestions
Salicylates
Toxic levels of aspirin will induce a metabolic acidosis
through the production of a number of organic acids. However presentation
is often with a respiratory alkalosis, through direct stimulation of the
respiratory centre.
Diagnosis is made by measurement of blood salicylate levels.
Methanol / Ethylene glycol
Metabolic acidosis results, because the metabolic products of
these molecules are organic acids:
Methanol → Formic aid
Ethylene glycol → Glyoxylic acid + Oxalic acid
Diagnosis is suspected on the basis of the history and the the finding of unaccounted osmoles in the blood (an osmolar gap):
Osmolar gap = Measured serum osmolality - (2 x [Na+] + glucose + urea)
The diagnosis is confirmed by measuring the toxic substance directly in the blood.
The treatment of these poisonings is by the administration of intravenous ethanol to saturate the enzyme, alcohol dehydrogenase, which is responsible for the production of the toxic breakdown products + dialysis to remove the substances.