MEDizzy - A patient with metabolic acidosis, reduced anion gap, and

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Introduction to clinical medicine

A patient with metabolic acidosis, reduced anion gap, and increased osmolal gap is most likely to have which of the following toxic ingestions?

ExplanationLithium interferes with cell membrane ion transport, leading to nephrogenic diabetes insipidus and falsely elevated chloride. This can cause the appearance of low anion gap metabolic acidosis. Sequelae include nausea, vomiting, ataxia, encephalopathy, coma, seizures, arrhythmia, hyperthermia, permanent movement disorder, and encephalopathy. Severe cases are treated with bowel irrigation, endoscopic removal of long-acting formulations, hydration, and sometimes hemodialysis. Care should be taken because toxicity occurs at lower levels in chronic toxicity compared with acute toxicity. Salicylate toxicity leads to a normal osmolal gap as well as an elevated anion gap metabolic acidosis, respiratory alkalosis, and sometimes normal anion gap metabolic acidosis. Methanol toxicity is associated with blindness and is characterized by an increased anion gap metabolic acidosis, normal lactate and ketones, and a high osmolal gap. Propylene glycol toxicity causes an increased anion gap metabolic acidosis with elevated lactate and a high osmolal gap. The only electrolyte abnormalities associated with opiate overdose are compensatory to a primary respiratory acidosis.