Vitamins (Mixed Deck)

Question 1

Name fat soluble vitamins.

Answer 1

A, D, E, K

Question 2

Malabsorption syndromes with steatorrhea include which vitamins, and which conditions may cause this?

Answer 2

• Fat-soluble vitamins (A, D, E, K)

- Cystic Fibrosis, Celiac Disease, Biliary stenosis, pancreatic insufficiency

Question 3

Function and vitamin derivation of Retinal.

Answer 3

Visual processes (deficiency leads to night blindness). Vitamin A.

Question 4

Function and vitamin derivation of Retinoic Acid.

Answer 4

Vitamin A.
Regulation of genes involved in growth and differentiation as well as differentiation and maintenance of mucus-secreting cells.
Relevant for SKIN (acne) and membranes of EYES (cornea and conjunctiva)
*Teratogenic– cannot be used during pregnancy or lactation

Question 5

Vitamin cause of xeropthalmia.

Answer 5

Vitamin A deficiency –> causes pathological dryness of the conjunctiva and cornea, which can lead to corneal ulceration

Question 6

Vitamin cause of foamy appearance on the conjunctiva.

Answer 6

Vitamin A deficiency

Question 7

Night blindness

Answer 7

Vitamin A deficiency

Question 8

Papilledema and headaches

Answer 8

Hypervitaminosis A (vitamin A toxicity)

Question 9

Potential cause of osteoporosis or joint pain

Answer 9

Hypervitaminosis A (vitamin A toxicity)

Question 10

Active form of vitamin D, and where is it formed?

Answer 10

Calcitriol or 1,25-dihydroxy vitamin D

Liver

Question 11

Predominant form of vitamin D in circulation, and where is it formed?

Answer 11

Calcidiol or 25-hydroxy Vitamin D

Kidney

Question 12

Primary function of vitamin D

Answer 12

regulation of plasma Calcium homeostasis

Question 13

Rickets

Answer 13

vitamin D deficiency (in children)

Due to incomplete mineralization

Question 14

Osteomalacia

Answer 14

Vitamin D deficiency (in adults)
Due to demineralization

**Not to be confused with osteoporosis!!

Question 15

Symptoms: loss of appetite, stupor. Lab tests show hypercalcemina and hypercalciuria.

Answer 15

Vitamin D EXCESS/toxicity

Question 16

Lab results:
Ca2+ = normal
PO4^2- = low
PTH = high
calcitriol = low
calcidiol = low
1-hydroxylase = high
alkaline phosphatase = high

Answer 16

Changes associated with Vitamin D deficiency

Question 17

Vitamin E function

Answer 17

antioxidant (protects cell membranes from free radicals)

Question 18

Who is at risk for vitamin E deficiency?

Answer 18

fat-malabsorption syndrome
fat-free diet
abetalipoproteinemia
defective a-tocopherol transfer protein

Question 19

Majority of plasma Vitamin E form…

Answer 19

a-tocopherol

Question 20

dicumarol

Answer 20

anti-vitamin K compound

Question 21

warfarin

Answer 21

anti-vitamin K compound

Question 22

Function of Vitamin K

Answer 22

hemostasis (e.g. prothrombin)
bone metabolism (e.g. osteocalcin)

Question 23

Vitamin K deficiency

Answer 23

RARE, newborns more likely

symptoms: bleeding, hypothrombinemia, increased prothrombin time(***)

Question 24

Vitamin K toxicity

Answer 24

hemolytic anemia, jaundice

toxic effect on RBC membrane

Question 25

Name the vitamin that is absorbed in the ileum and form it is absorbed as.

Answer 25

B12/Cobalamin Absorbed as IF-Cobalamin (intrinsic factor)

Question 26

In the absorption of Cobalamin (B12), where and by what is intrinsic factor secreted?

Answer 26

Stomach, by parietal cells

Question 27

Cyanide poisoning can be remedied by administration of what vitamin (and in what form)?

Answer 27

Cobalamin (B12), as Hydroxy-Cobalamin

Question 28

Vitamin B9 also called....

Answer 28

Folate/Folic Acid

Question 29

Predominant circulating form of folate?

Answer 29

N5-methyltetrahydrofolate (N5-methyl-THF)

Question 30

Most direct function of folate...

Answer 30

Synthesis of purines and pyrimidines

Question 31

Folate overlaps with which other vitamins?

Answer 31

B12 (cobalamin) and B6 (pyridoxine)

Question 32

Folate deficiency in adult causes...

Answer 32

Decreased synthesis of purines and pyrimidines, leading to.... Megaloblastic anemia Hyperhomocysteinemia (which increases risk for cardiovascular symptoms)

Question 33

What would you see on a peripheral blood smear in someone who has a folate deficiency?

Answer 33

- oval/orb-shaped RBCs - Hyper-segmented WBCs (more than 3) - Excess reticulocytes

Question 34

Folate deficiency during pregnancy causes...

Answer 34

Neural tube defects in babies... | Can result in spina bifida, encephalies, etc

Question 35

Cofactor for Methionine Synthase (homocysteine methyltransferase)

Answer 35

B12 (cobalamin) as methylcobalamin

Question 36

Cofactor for Methylmalonyl-CoA Mutase

Answer 36

B12 (cobalamin) as 5'-deoxyadenosylcobalamin

Question 37

Cobalamin (B12) is a cofactor for 2 reactions which produce what two products?

Answer 37

1. Methionine | 2. Succinyl-CoA

Question 38

Why would chronic proton-pump inhibitor cause B12 (Cobalamin) deficiency?

Answer 38

Cobalamin can't dissociate from protein after ingestion due to decreased acid in stomach, which causes release of Cobalamin from protein, and allows subsequent binding of Cobalamin to Haptocorrin.

Question 39

B12 (Cobalamin) deficiency also causes what secondary deficiency? How can the two deficiencies be differentiated?

Answer 39

- B9 (folate) - Both will cause hyperhomocysteinemia and megaloblastic anemia, but Cobalamin deficiency will also cause accumulation of methylmalonate and proprionate

Question 40

what is pernicious anemia?

Answer 40

severe vitamin B12 (cobalamin) deficiency due to autoimmunity against gastric parietal cells or intrinsic factor