Toxicology

Acetaminophen overdose management follows the Rumack-Matthew nomogram, which plots serum acetaminophen concentration against time since ingestion to determine the need for N-acetylcysteine (NAC) therapy. NAC is most effective when started within 8 hours of ingestion, reducing hepatotoxicity from 60% to near-zero when initiated within this window.

Toxidrome recognition using the anion gap metabolic acidosis, osmolar gap, and specific toxidrome patterns (anticholinergic, cholinergic, sympathomimetic, opioid, sedative-hypnotic) enables rapid identification of the ingestant class and guides empirical treatment before confirmatory laboratory results are available.

Salicylate poisoning severity is assessed using the Done nomogram (now largely historical; clinical severity grading preferred), with serial serum salicylate levels, arterial blood gas analysis, and clinical signs guiding the decision for urinary alkalinization versus hemodialysis. Methemoglobinemia from oxidizing agents is quantified using co-oximetry, with levels >20% typically warranting methylene blue therapy.