Uncoventional Views on Certain Aspects of Toxin-Induced Metabolic Acidosis

ABSTRACT

This discussion will highlight the following 9 specific points that related to metabolic acidosis caused by various toxins. The current recommendation suggests that alcohol dehydrogenase inhibitor fomepizole is preferred to ethanol in treatment of methanol and ethylene glycol poisoning, but analysis of the enzyme kinetics indicates that ethanol is a better alternative. In the presence of a modest increase in serum osmolal gap (<30 mOsm/L), the starting dose of ethanol should be far less than the usual recommended dose. One can take advantage of the high vapor pressure of methanol in the treatment of methanol poisoning when hemodialysis is not readily available. Profuse sweating with increased water ingestion can be highly effective in reducing methanol levels. Impaired production of ammonia by the proximal tubule of the kidney plays a major role in the development of metabolic acidosis in pyroglutamic acidosis. Glycine, not oxalate, is the main final end product of ethylene glycol metabolism. Metabolism of ethylene glycol to oxalate, albeit important clinically, represents less than 1% of ethylene glycol disposal. Urine osmolal gap would be useful in the diagnosis of ethylene glycol poisoning, but not in methanol poisoning. Hemodialysis is important in the treatment of methanol poisoning and ethylene glycol poisoning with renal impairment, with or without fomepizole or ethanol treatment. Severe leucocytosis is a highly sensitive indicator of ethylene glycol poisoning. Uncoupling of oxidative phosphorylation by salicylate can explain most of the manifestations of salicylate poisoning.