A visual schematic for clarifying the temporal relationship between the anion and osmol gaps in toxic alcohol poisoning

Delayed treatment of ethylene glycol or methanol poisoning can result in life-threatening complications, but obtaining quantitative levels is delayed by several hours in most hospitals. Calculating the anion gap and the osmol gap are recommended to hasten identification and treatment in cases of suspected toxic alcohol poisoning. However, relying on the anion and osmol gap calculations without understanding the temporal relationship between these 2 gaps can lead to delayed identification and increased morbidity in cases of toxic alcohol poisoning. Our “Mountain” schematic illustrates the presence of an elevated osmol gap found early in toxic alcohol poisoning and the presence of an elevated anion gap found later in the course of poisoning. Using the “Mountain” diagram as a clarification of the temporal relationship between the anion and the osmol gap can improve the diagnostic use of these screening assays.