91b - Neurology and Nutrition

Question 1

What are the signs of Wernicke’s Encephalopathy?

What is it caused by?

Answer 1

• Ataxia
• Abnormal eye movements
  
  • Nystagmus
• Confusion

Caused by thiamine deficiency - treat with thiamine to prevent Korsakoff symptoms!

(Amnesia, confabulation, peripheral neruopathy)

Question 2

What is pellagra?

What are the signs?

Answer 2

Pellagra = Niacin (B3) deficiency

Dermatitis, Diarrhea, Dementia

• Often seen in people who have malnourishment + alcohol use disorder
• Often in underdeveloped countries

Question 3

Methotrexate is associated with what deficiency?

Answer 3

Folate (B9)

Question 4

What is the appearance of Wernicke’s encephalopathy on MRI?

Answer 4

Medial thalami and mamillary body hyperintensity

Question 5

What are the symptoms of pyridoxine (B6) deficiency/

Answer 5

Sensory polyneuropathy

Often caused by treatmetn with isoniazid

Question 6

Dermatitis, dementia, and diarrhea are signs of which vitamin deficiency?

Answer 6

Niacin (B3) deficiency

Question 7

What is the treatment for cobalamin (B12) deficiency?

Answer 7

B12 supplementation for life

Question 8

Isoniazid is associated with which deficiency?

Answer 8

Pyridoxine (B6)

Question 9

How is thiamine deficiency treated?

Answer 9

Give thiamine (B1) before or concurrently with glucose

• Giving glucose before thiamine will make thiamine deficiency worse, because thiamine is needed to metabolize glucose

Question 10

Mamillary body hyperintensity is pathognomonic for which deficiency?

Answer 10

Thiamine deficiency

However, imaging will more commonly show hyperintensity of the medial thalami

May also see hyperintensity in the periaqueductal grey

Question 11

Which syndrome is associated with cobalmin (B12) deficiency?

What are the symptoms?

Answer 11

Subacute combined degeneration

• Affects corticospinal and dorsal column
• Mild weakness
• Paresthesias
• Ataxic paraplegia
  
  • Unsteadiness, stiffness/weakness in legs
• Cognitive changes
  
  • Irritability, apathy, somnolence
• Scotoma

Irritable, unsteady, pins and needles, blind spot

Question 12

Which labs should be checked in a patient with suspected cobalamin (B12) deficiency?

Answer 12

• Serum B12
  
  • <100 will have neurological symptoms
  • <200 needs further eval even w/o symtpoms
  • 200-300 may still be deficient
• Homocysteine
  
  • If high => intracellular B12 deficiency
• Methylmalonic acid
  
  • If high => intracellular B12 deficiency
• Antibody to IF
• Megaloblastic anemia

Question 13

Which syndromes may be caused by thiamine (B1) deficiency?

Answer 13

• Wernicke-Korsakoff
  
  • Ataxia, confusion, abnormal eye movements
  • Followed by psychosis (amnesia, confabulation) and neuropathy
• Beri Beri
  
  • Length-dependent peripheral polyneuropathy +/- edema

Question 14

Deficiency of which vitamin is associated with subacute combined degeneration?

Describe the symtoms

Answer 14

Cobalamin (B12) deficiency)

• Weakness
• Paresthesia
• Gait unsteadiness, stiffness/weakness in legs
• Irritability, apathy, somnolence
• Scotoma

Question 15

High levels of which compounds indicate intracellular cobalamin (B12) deficiency?

Answer 15

Homocysteine

Methylmalonic acid

May indicate cobalamin deficiency even if cobalamin levels are normal