Ethylene glycol toxicity presenting as a rapidly deteriorating focal neurological exam and reversible cerebral herniation syndrome.

Ethylene glycol toxicity is an exceedingly rare toxic encephalopathy. Ethylene glycol is the primary toxin in antifreeze and exhibits its toxicologic effects via metabolites glycolic and oxalic acids, driving a profound metabolic acidemia. Classically, ethylene glycol toxicity presents as inebriation without focal neurological deficits. Here we describe a case of a healthy older adult who ingested antifreeze and presented with 1 h of dysarthria, left-sided facial droop, and left-sided hemiplegia and rapidly progressed to a clinical cerebral herniation syndrome from which he ultimately fully recovered. This case is an example of the breadth of altered mental status presentations that are possible with ethylene glycol toxicity, while modeling the classic laboratory and imaging findings of the toxic encephalopathy. The epidemiology, pathophysiology, diagnosis, management, and prognosis of ethylene glycol toxicity will be discussed.