Pathophysiology
Clinical meaning
Advanced toxicological management by the clinician requires systematic approach to complex poisoning presentations including multi-drug ingestions, delayed-onset toxicity, and environmental exposures. Digoxin toxicity results from inhibition of the sodium-potassium ATPase pump, causing intracellular calcium accumulation with characteristic ECG findings (scooped ST segments, bidirectional VT, regularized atrial fibrillation) — digoxin-specific antibody fragments (Digibind) are indicated for life-threatening dysrhythmias, hyperkalemia > 5.5 mEq/L, or hemodynamic instability. Methanol and ethylene glycol poisoning produce toxic metabolites (formic acid and oxalic acid respectively) through alcohol dehydrogenase metabolism, causing metabolic acidosis with elevated osmolar gap — treatment includes fomepizole (alcohol dehydrogenase inhibitor) and hemodialysis for severe toxicity. The clinician must understand toxicokinetics, calculate anion and osmolar gaps, and coordinate poison control center consultation for rare or complex exposures.