Snapshot A 40-year-old man is brought to the emergency department due to lethargy and confusion. The patient is accompanied by his friend, who reports he has been having trouble decreasing his alcohol consumption. Per his friend, the patient has 20 years of alcohol use. On physical examination, the patient has horizontal nystagmus and is ataxic. He is immediately started on intravenous thiamine. (Wernicke encephalopathy) Introduction Vitamin B1 is a water soluble vitamin (and thus excreted in the urine) the biologically active form of this vitamin is thiamine pyrophosphate (TPP) Biochemistry TPP serves as a coenzyme for transketolase which is involved in the hexose-monophosphate shunt α-ketoglutarate dehydrogenase which is involved in the citric acid cycle pyruvate dehydrogenase branched-chain ketoacid dehydrogenase Clinical correlate thiamine deficiency can result in decreased ATP production because of thiamine's role in dehydrogenase-catalyzed reactions involved in energy production therefore, neurons are highly susceptible to impaired cellular function thiamine deficiency results from chronic alcoholism due to inadequate dietary intake or impaired absorption diet mainly composed of polished rice thiamine deficiency results in Wernicke-Korsakoff syndrome can be seen in chronic alcohol use beriberi can be divided into wet beriberi secondary to cardiac dysfunction treatment: thiamine supplementation dry beriberi resulting in symmetrical peripheral neuropathy