A 59-year-old male is brought to the emergency department by the EMS after
a family member found him extremely confused and disoriented, with an
unsteady gait and strange irregular eye movements. The patient has been
known in the past to be a heavy drinker. He has no known medical problems
and denies any other drug usage. On examination, he is afebrile with a pulse
of 110 beats per minute and a normal blood pressure. He is extremely disori-
ented and agitated. Horizontal rapid eye movement on lateral gaze is noted
bilaterally. His gait is very unsteady. The remainder of his examination is nor-
mal. The urine drug screen was negative and he had a positive blood alcohol
level. The emergency room physician administers thiamine.
What is the most likely diagnosis?
What is importance of thiamine in biochemical reactions?