Vitamin deficiencies and toxicities Flashcards Preview

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Flashcards in Vitamin deficiencies and toxicities Deck (28):
1

B1 - reactions

Thiamine - Pyruvate Dehydrogenase, alphaketoglutarate dehydrogenase, HMP shunt (transketolase), Branched-chain AA dehydrogenase

2

B1 deficiency

ATP depletion - Dry and wet BeriBeri - heart and brain affected first; Wernicke= ophthalmoplegia, mental status, ataxia; Korsakoff- memory, confabulation, personality change

3

B2 reaction and deficiency

FADH2, Riboflavin; Cheilosis and corneal vascularization

4

B3 reaction

NAD, NADP; derived from tryptophan; synthesis requires B6

5

B3 deficiency

pallagra (dementia, diarrhea, dermititis), aggression, confusion, ataxia; caused by Hartnup disease, INH use, Carcinoid

6

B3 excess

Facial flushing that can be lessened by taking aspirin

7

B5

Pentothenate; essential component of CoA (acyl transfers, TCA cycle, FA synthesis); deficiency dermatitis, enteritis, alopecia, ADRENAL INSUFFICIENCY (important in cholesterol synthesis)

8

B6 reactions

Pyridoxine - glutamate to GABA, Glycine to Heme, Tryptophan to naicin, Homocystein to cysteine and SAM, Histidine to Histamine, Dopa to Dopamine,

9

B6 shortage

convulsions (absence of gaba), sideroblastic anemia from inhibition of ALA synthase, peripheral neuropathy; deficiency inducible by INH or oral contraceptives

10

B12 reactions

Homocystein to methionine and mehylalonyl-CoA to Succinyl CoA

11

B12 deficiency

Macrocytic, megaloblastic anemia; peripheral neuropaty; dorsal column and lateral corticospinal tract dysfunction (all due to abnormal myelin); causes: celiac, Crohn, diphyllobothrium latum, pernicious anemia; test with Schilling test

12

Folic Acid function

Active form is tetrahydrofolate. Is a carbon donor. Synthesis in nitrogenous bases for DNA and RNA. Activated form is made in homocystein to methionine reaction with B12.

13

Folic Acid Deficiency

Macrocytic, megaloblastic anemia; no neurologic symptoms. Most common in US. Alcoholism and pregnancy. Caused by drugs (phenytoin, sulfonamides, MTX); excess can exacerbate any B12 deficiency

14

SAM

made from ATP and methionine. Methyl donor. Used for Epinepherine to epinepherine conversion; Used for methylation of 5' guanosine cap during mRNA processing

15

Biotin function

Carboxylation; propionyl-CoA to Methylmalonyl CoA (odd-chain Fas); Pyruvate carboxylase (start of gluconeogenesis); Acetyl-CoA carboxylase (Acetyl-CoA to Malonyl CoA to start off FA synthesis)

16

Biotin deficiency

Alopecia, gastroenteritis, Dermatitis; Caused by antibiotic use or excessive ingestion of RAW EGGS

17

Vitamin C Function

Hydroxylation of Lysine and proline; absorption of Fe and maintenance of ferrous state; cofactor for dopamine to NE.

18

Vit C defenciency

Scurvy- swollen gums, bruising, hemarthrosis, anemia, poor wound healing, weakened immune response, (anemia is due to poor Fe intake and extensive oxidative damage to RBCs as Vit C is an antioxidant)

19

Excess of Vit C

Fe overload especially those at risk like people with hemochromatosis; Nausea, vomiting, idarrhea, fatigue, sleep problems

20

Vitamin A function

Antioxidant; visual pigments (retinal); normal differentiation of specialized epithelium (prevents squamous metaplasia); used to treat measles and M3 AML; topical for wrinkles and acne

21

Vit. A deficiency

Night blindness, dry skin, squamous metaplasia of conjunctiva (Bitot's spots), xerophthalmia

22

Vit. A excess

Arthralgias, fatigue, headache, SKIN CHANGES, sore throat, alopecia, teratogenic, increases in CSF pressure (can sometimes see cerebral edema through opthalmoscope)

23

Vit. D excess

hypercalcemia, hypercalciuria. Abdominal pains. Seen in sarcoidosis because epithelioid cells

24

Vit D.

Ergocalciferol (D2 - plants); Cholecalciferol (D3 - skin); 1,25-calcitrol (active)

25

Vit E

alpha-tocopherol; antioxidant protects erythrocytes and membranes from free-radical damage

26

Vit E deficiency

Fragility of erythrocytes, muscle weakness; Posterior column and spinocerebellar tract demyelination.

27

Vit. K

gamma carboxylation of glutamic acid residues on factors 2, 7, 9, 10 C and S. Deficiency leads to hemorrhage (neonates are susceptible from lack of intestinal flora)

28

Zinc deficiency

Functions in 100+ enzymes, zinc-finger transcription factor, carbonic anhydrase; deficiency leads to defect in synthesis of proteins etc.; delayed wound healing, hypogonadism, decreased adult hari, changes in taste dygeusia, changes in smell anosmia, impaired night vision, infertility, rash of eyes mouth nose and anus.