91. Nutrition and Neurology

Question 1

Thiamine (B1) Deficiency

• use of thiamine
• 2 disease types with sx, imaging, tx

Answer 1

B1: cofactor in 2 steps of Krebs cycle (critical in high energy areas - CNS); deficiency prevented through bread enrichment

Wernicke-Korsakoff Syndrome: Encephalopathy (Nystagmus, Opthalmoparesis, Gait ataxia, confusion) and Psychosis (anterograde/retrograde amnesia, no insight, confabulation - wrongly filling in memory gaps) and Peripheral neuropathy
Labs: low B1
Imaging: HYPERINTENSE MAMMILLARY BODY
Tx: EMERGENT HIGH DOSE B1 (do not give glucose before thiamine - will worsen sx)

Beriberi: affects heart/peripheral nerves
Wet type: with peripheral edema; Dry type: without peripheral edema
sx: length-dependent peripheral polyneuropathy (burning pain, weakness, hyporeflexia)
tx: thiamine

Question 2

Niacin (B3) Deficiency

• use of B3
• disease, sx, tx

Answer 2

B3: precursor to NAD coenzyme
Pellagra: in malnourished alcoholics, underdeveloped maize-eating populations
sx: Dermatitis (hyperpigmentation), Dementia, Diarrhea; fatigue, anxiety, depression, irritability
tx: Niacin

Question 3

Pyridoxine (B6) Deficiency

• use
• dz cause
• sx
• tx

Answer 3

Conversion of homocysteine to cystathionone
Deficiency due to isoniazid use (TB tx) - inhibits B6
sx: sensory polyneuropathy (paresthesia, pain, weakness)
tx: Pyroxidine

Question 4

Folate (B9) Deficiency

• use
• dz cause
• sx
• tx

Answer 4

DNA synthesis
deficiency with MTX use (inhibits folate metabolism)
Sx: peripheral neuropathy, neural tube defects in pregnancy
Tx: Folic acid supplementation

Question 5

Cobalamin (B12) Deficiency

• use
• dz cause
• sx
• PE
• Imaging
• tx

Answer 5

found in dairy/meat/fish; cofactor for homocysteine - methionine (folate - DNA synthesis); cofactor for methylmalonyl CoA mutase (Odd Chain FA metabolism)

Deficiency: due to malabsorption (pernicious anemia, gastritis, poor nutrition, metformin use)
Sx: Subacute combined degeneration (generalized weakness - CS, paresthesias in hands/feet - Dorsal col), ataxic gait, cognitive irritability/apathy, optic scotomas
PE: no vibration, no proprioception, spasticity, clonus, hyperreflexia
Imaging: hyperintensity along SC
tx: B12 for life