Adult thiamine deficiency may present as Wernicke's encephalopathy or beriberi. It can be difficult to recognize. A patient with thiamine deficiency may present with a combination of metabolic acidosis, increased anion gap and respiratory alkalosis.

Thiamine is essential for normal activity of pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase. Defects in their activity results in a metabolic acidosis associated with an accumlation of pyruvate, lactate, alpha-ketobutyrate and other acidic compounds.



(1) metabolic acidosis

(1a) depressed serum bicarbonate

(1b) usually lactic acidosis

(1c) increased anion gap

(2) pH >= 7.42 (upper normal to alkalosis)

(3) moderate to marked decrease in PaCO2


The diagnosis of Wernicke's encephalopathy should be considered when there is no alternative explanation for these findings, particularly salicylate intoxication.

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