- Also called thiamine.
- Function
- In thiamine pyrophosphate (TPP), a cofactor for several dehydrogenase enzyme reactions:
- α-ketoglutarate dehydrogenase (TCA cycle)
- Transketolase (HMP shunt)
- Branched-chain ketoacid dehydrogenase (catabolism of branched chain amino acids leucine, isoleucine & valine)
- Pyruvate dehydrogenase (links glycolysis to TCA cycle)
- Think ATBP
- In thiamine pyrophosphate (TPP), a cofactor for several dehydrogenase enzyme reactions:
- Deficiency:
- Impaired glucose breakdown → ATP depletion worsened by glucose infusion (increased metabolites of glucose); highly aerobic tissues (eg, brain, heart) are affected first.
- In alcoholic or malnourished patients, give thiamine before dextrose to ↓ risk of precipitating Wernicke encephalopathy.
- Diagnosis made by ↑ in RBC transketolase activity following vitamin B1 administration.
- Spell beriberi as Ber1Ber1 to remember vitamin B1.
- Wernicke-Korsakoff syndrome
- Wernicke syndrome (classic triad)):
- Confusion: Disorientation, apathy, decreased attention span. Responds well to treatment.
- Ophthalmoplegia: Damage to CN III, IV, and vestibular nuclei. Rapidly reversible.
- Ataxia: Damage to cerebellar cortex, vestibular nuclei. Takes longer to resolve, may be permanent.
- Korsakoff syndrome: Damage to anterior and medial dorsal nucleus of thalamus, mammillary bodies.
- Confabulation (when unsure of a fact, will fill in with a fabricated story that they themselves believe to be true)
- Personality change
- Memory loss, anterograde amnesia (permanent).
- Wernicke syndrome (classic triad)):
- Dry beriberi—polyneuropathy, symmetrical muscle wasting.
- Wet beriberi—high-output cardiac failure (dilated cardiomyopathy), edema.