Which patients hospitalized with alcohol withdrawal syndrome should receive high-dose parenteral thiamine?

The three compartments above represent the gastrointestinal tract lumen on the left, the blood in the middle, and the brain on the right. The size of the green ovals is proportional to the concentrations of thiamine in each compartment, and the width of the arrows is proportional to the amount of uptake by each mechanism. The three rows diagram a schematic representation of (A) oral thiamine absorption under normal conditions, (B) oral thiamine absorption in the setting of chronic alcohol use, and (C) parenteral thiamine administration in the setting of chronic alcohol use. Under normal conditions, most uptake from the gastrointestinal tract to the blood and from the blood to the brain occurs via a membrane-bound transporter (white arrows) and little occurs via passive diffusion (black arrows). The relative proportions are altered in chronic alcohol use and with the administration of parenteral thiamine.