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Flashcards in Biochem - Nutrition/Vitamins Deck (81):
1

cobalamin deficiency can cause these 4 sx:

  • Macrocytic, megaloblastic anemia
  • hypersegmented PMNs
  • paresthesias
  • subacute combined degeneration of dorsal columns, lateral corticospinal tracts, and spinocerebellar tracts) due to abnormal myelin.

2

Marasmus

energy malnutrition, muscle wasting

3

outcomes of Vitamin A deficiency  5

  • Night blindness (nyctalopia)
  • dry, scaly skin (xerosis cutis)
  • alopecia
  • corneal degeneration (keratomalacia)
  • immune suppression.

4

pathophysiology of giving glucose to a vitamin B1 deficient patient

If thiamine/B1 deficient patient is given glucose infusion first, pyruvate-->acetyl CoA won't work and all the substrates gets funneled to making lactate --> acidosis --> death.

Highly aerobic tissues (e.g., brain, heart) are affected first!

5

a cofactor used in transamination (e.g., ALT and AST), decarboxylation reactions, glycogen phosphorylase.

B6 (pyridoxine)

6

3 supplements you must give to a breast-fed neonate

1) vitamin D - promote intestinal absorption of Ca and bone mineralization

2) Vitamin K - prevent bleeding diathesis

3) Fe (prevent IDA)

7

causes of calcium oxalate nephrolithiasis?

common presentation?

trmt?

causes

  • ethylene glycol (antifreeze)
  • vitamin C abuse
  • Crohn disease (malabsorption of fats)

presentation: calcium oxalate stone in a patient with hypercalciuria and normocalcemia.

treatment: thiazides and citrate.

8

Folate - which vitamin?

B9

9

this vitamin deficiency is inducible by isoniazid and oral contraceptives, and it causes these symptoms

B6 ∆

Convulsions

Hyperirritability

Peripheral neuropathy

Sideroblastic anemias (impaired hemoglobin synthesis and iron excess)

B3 deficiency -> pellagra

10

storage pool of folic acid vs storage pool of cobalamin?

Folic acid (b9) = Small reserve pool stored primarily in the liver.

Cobalamin (b12) = large reserve pool (several years) stored primarily in the liver

11

Diarrhea

Dementia (also hallucinations)

Dermatitis (casal necklace or hyperpigmentation of sun-exposed limbs)

Pellagra (vitamin B3 deficiency" The 3 D’s of B3

12

vitamin B3 (niacin)

function

causes of deficiency - 3

how deficiency presents

excess

  • function: part of NAD+ and NADP+, made from Trp, requires B6 to be synthesized
  • deficiency caused by
    • associated with Hartnup disease
    • carcinoid syndrome
    • INH use in tuberculosis
  • presentation: 3D's diarrhea, dermatitis, dementia (pellagra)
  • excess: hot flashes, facial flushing

13

Niacin

derived from:

requires these two factors to form:

forms these two factors

derived from trypotophan

requires B2 and B6

forms NAD+, NADP+ (used in redox reactions)

14

biotin - which vitamin?

B7

15

Vitamin A excess - 6

  • Teratogen
  • Skin ∆s (scaliness)
  • alopecia
  • cerebral edema "pseudotumor cerebri"
  • osteoporosis
  • hepatic abnormalities

16

Folic acid deficiency can be caused by these Rx

phenytoin, sulfonamides, methotrexate

17

vitamin B9 (folic acid)

function?

3 outcomes of deficiency?

causes of deficiency? 4

function: converted to THF and used in DNA/RNA synthesis

deficiency results in: 

  • intrauterine neural tube defects
  • macrocytic anemia (with hypersegmentation)
  • increased homocystine levels

deficiency caused by: MTX, TMP-SMX, phenytoin, alcoholics and pregnancy

 

18

Niacin is used to treat:

dyslipidemia; lowers levels of VLDL and raises levels of HDL.

19

Total calorie malnutrition resulting in tissue and muscle wasting, loss of subcutaneous fat, and variable edema.

Marasmus = Muscle wasting.

20

3 causes of vitamin K deficiency:

  • warfarin
  • neonates (sterile intestines - remember Vit K is made by intestinal flora)
  • Antibiotic use (kills off intestinal flora)

21

vitamin B1 (thiamine)

function?

deficiency?

function: cofactor for alpha-ketoglutarate DH, transketolase, pyruvate DH, branched-chain amino acid DH

deficiency: wet + dry beriberi, Wernicke-Korsakoff









 

22

zinc

function?

deficiency?

function: widespread, transcription factors

deficiency: metallic taste, delayed wound healing, hypogonadism, acrodermatitis enteropathica




 

23

folic acid is initially converted into:

THF (a coenzyme required to convert homocysteine into methionine)

24

vitamin B2 (riboflavin)

function

how deficiency presents

function: cofactor for FADH2 (oxidation and reduction)

deficiency: cheilosis, corneal vascularization

25

Folic acid deficiency can cause these 3 sx and labs

Macrocytic, megaloblastic anemia

hypersegmented PMNs

Glossitis

increased Homocystine, normal MMA

NO neurologic symptoms (as opposed to vitamin B12 deficiency).

26

treatment of cobalamin deficiency with folic acid results in

subacute combined degeneration of dorsal columns.

27

Hemolytic anemia, acanthocytosis, muscle weakness, posterior column and spinocerebellar tract demyelination.

Vitamin E deficiency (tocopherol/tocotrienol)

28

Essential component of coenzyme A and fatty acid synthase.

Vitamin B5 (pantothenate)

29

vitamin B6 (pyridoxine)

function:

  • cofactor in transamination, decarboxylation, glycogen phosphorylase
  • synthesis of heme, histamine, niacin, 5-HT, EPI, NE, GABA

deficiency: peripheral neuropathy, sideroblastic anemia
 

30

niacin - which vitamin?

B3

31

Vitamin B1 deficiency

Wernicke-Korsakoff syndrome and beriberi (Ber1Ber1)

32

labs of cobalamin deficiency

incr. serum homocysteine AND methylmalonic acid levels.

33

drug for alcoholics to take to decrease intake

Disulfiram - inhibits acetaldehyde dehydrogenase (acetaldehyde accumulates, contributing to instant hangover symptoms)

34

thiamine - which vitamin?

B1

35

high-output cardiac failure (dilated cardiomyopathy), edema.

Wet beriberi due to thiamine B1 deficiency

36

wet beriberi

 

 

 

high-output cardiac failure due to thiamine deficiency

37

pantothenic acid - which vitamin?

B5

38

eating too much raw eggs will cause deficiency in this

B7 deficiency "Avidin in egg whites avidly binds biotin.”

39

vitamin B7 (biotin)

function

deficiency

function: cofactor for carboxylation (adds 1 carbon) in pyruvate carboxylase, acetyl-CoA carboxylase, and propionyl-CoA carboxylase

deficiency: dermatitis, alopecia, enteritis, associated with raw egg ingestion




 

40

vitamin E

function

how deficiency presents

fat-soluble

function: antioxidant for erythrocytes

deficiency: hemolytic anemia, neuropathy

41

dry beriberi

polyneuritis and muscle wasting

due to thiamine deficiency

42

cobalamin deficiency caused by: 4 

1) insufficient intake (veganism)

2) malabsorption (sprue, enteritis, diphyllobothrium latum)

3) lack of IF (pernicious anemia, bypass surgery)

4) absence of terminal ileum (Crohn disease, resection).

43

ascorbic acid - which vitamin?

Vitamin C

44

one malignancy that causes increase vitamin D?

Sarcoidosis (incr. activation of vitamin D by epithelioid macrophages).

45

vitamin B12 (cobalamin)

function?

outcomes of deficiency?

possible causes of deficiency?

diagnosed by?

 

  • function: cofactor that helps convert methylmalonyl-CoA to succinyl-CoA and homocysteine to methionine
  • deficiency: 
    • megaloblastic anemia (with hypersegmentation)
    • peripheral neuropathy
    • sub-acute degeneration of the spinal cord
    • increased MMA + homocystine levels
  • deficiency causes: rare due to liver stores
    • diphyllobothrium latum tapeworm
    • autoimmune (pernicious anemia)
    • anatomic (gastric bypass)
    • malabsorption (celiac disease), inflammatory (IBD)
  • deficiency diagnosed by Schilling test

46

retinol - which vitamin?

Vitamin A

47

B2 forms these two factors:

FAD and FMN are derived from riboFlavin (B2 = 2 ATP).

48

vitamin K

function

deficiency

causes of deficiency 3

fat-soluble

function: catalyses gamma-carboxylation → synthesis of clotting factors (2, 7, 9, 10, C, S)

deficiency: neonatal bleeding (must give vitamin K IM shot at birth)

causes of deficiency:

  • abx use (synthesized by intestinal flora)
  • warfarin (coumadin) acts as an antagonist to create a functional deficiency
  • neonates

49

Delayed wound healing

hypogonadism

decreased adult hair (axillary, facial, pubic)

dysgeusia

anosmia

acrodermatitis enteropathica

zinc deficiency

50

vitamin D

function?

deficiency?

excess?

excess production is related to this one d/o! (HIGH YIELD POINT)

fat-soluble

function: absorption of Ca and Phos, bone mineralizatoin

deficiency: 

  • rickets (children)
  • osteomalacia (adults)
  • hypocalcemia (can lead to 2ndary hyperparathyroidism)

excess: 

  • hypercalcemia → hypercalciuria → nephrolithiasis
  • causes
    • associated with granulomatous inflammation due to increased activity of 1-alpha hydroxylase by macrophages (e.g. sarcoidosis, tuberculosis)

 

51

Excess niacin cause these 3 sx

  • Facial flushing (induced by prostaglandins, not histamine)
  • hyperglycemia
  • hyperuricemia

52

Folic acid deficiency can cause these labs

incr. homocysteine

normal methylmalonic acid

53

Vitamin A can be used to treat these 2 diseases

measles AML, subtype 3

54

3 causes of niacin deficiency?

2 outcomes?

1) Hartnup disease (decr. tryptophan absorption)

2) malignant carcinoid syndrome (incr. tryptophan metabolism to make serotonin)

3) isoniazid (decr. vitamin B6).

outcomes: Glossitis + Pellagra

55

vitamin A (retinol)

function

deficiency

excess

can be used to treat

fat-soluble

function: antioxidant, prevents squamous metaplasia

deficiency: night blindness

excess: teratogenic, idiopathic intracranial hypertension (pseudotumor cerebri), alopecia

treats: acne and APL (AML type M3)

 

56

2 functions of retinol (Vit A)?

  • antioxidant- constituent of rods in retina- req'd for differentiation of epithelial cells --> pancreatic cells, mucus-secreting cells
  • prevents squamous metaplasia

57

polyneuritis, symmetrical muscle wasting.

Dry Beriberi, Thiamine deficiency

58

small child with swollen belly

Kwashiorkor - Protein malnutrition resulting in skin lesions, edema, liver malfunction (fatty change due to decreased apolipoprotein synthesis).

59

Vitamin D deficiency in children vs adults vs both

children: rickets (bone pain and deformity)

adults: osteomalacia (bone pain and muscle weakness)

both: hypocalcemic tetany

60

Vitamin E function?

Antioxidant (protects erythrocytes and membranes from free radical damage).

E is for Erythrocytes.Can enhance anticoagulant effects of warfarin

61

Dermatitis, enteritis, alopecia, adrenal insufficiency.

B5 is “pento”thenate

62

Patient with cheilosis & corneal vascularization

B2 deficiency (riboflavin)

63

How do difference B12 from Vitamin E deficiency?

Neurological presentation may appear similar to vitamin B12 deficiency but without

  • megaloblastic anemia
  • hypersegmented neutrophils
  • increased serum methylmalonic acid levels.

64

vitamin C (ascorbic acid)

function

how deficiency presents

how excess presents

  • function: antioxidant, collagen synthesis, NE synthesis
  • deficiency: scurvy
  • excess: GI symptoms, iron toxicity

65

this supplementation decreases risk of neural tube defects

folic acid

66

Sx of vitamin D excess?

Hypercalcemia, hypercalciuria, loss of appetite, stupor

67

vitamin B5 (pantothenate)

function?

deficiency?

function: part of CoA and fatty acid synthase

deficiency: dermatitis, alopecia, adrenal insufficiency




 

68

How to diagnose B1 deficiency?

measure increase in RBC transketolase activity following vitamin B1/thiamine administration.

69

confusion, ophthalmoplegia, ataxia

Wernicke-Korsakoff syndrome; also causes confabulation, personality change, permanent memory loss.

Causes damage to medial dorsal nucleus of thalamus, mammillary bodies (impt for recollective memory)

70

5 symptoms of B6 deficiency

  • Convulsions
  • Hyperirritability
  • Peripheral neuropathy
  • Sideroblastic anemias (impaired hemoglobin synthesis and iron excess)
  • according to Uworld: also seborrheic dermatitis, glossitis

71

cobalmin - which vitamin?

B12

72

riboflavin - which vitamin?

B2

73

If you see these dermatitis, alopecia, enteritis, you should think of:

B-complex deficiencies (B5, B7)

74

antidoate for methanol and ethylene glycol poisoning

fomepizole - inhibits alcohol dehydrogenase

75

swollen gums, bruising, hemarthrosis, anemia, poor wound healing, perifollicular and subperiosteal hemorrhages, “corkscrew” hair.

Vitamin C deficiency causes sCurvy due to a Collagen synthesis defect.

note: all the sx are related to collagen defects

76

Vitamin B1 function

THIAMINE cofactor in

  • Pyruvate dehydrogenase (links glycolysis to TCA cycle)
  • α-ketoglutarate dehydrogenase (TCA cycle)
  • Transketolase (HMP shunt)
  • Branched-chain ketoacid dehydrogenaseATP

77

Vitamin C functions - 4

  • Antioxidant.
  • Facilitates iron absorption by reducing it to Fe2+ state.
  • Necessary for hydroxylation of proline and lysine in collagen synthesis.
  • Necessary for dopamine β-hydroxylase, which converts dopamine to NE.

78

all vitamins wash out from the body except for these two:

B12 and folate (stored in liver).

79

pyridoxine - which vitamin?

B6

80

Kwashiorkor presentation and cause

small child with swollen belly

protein malnutrition, edema, anemia, fatty liver


 

81

how a patient with Wernicke-Korsakoff presents

  • ataxia, memory loss, confabulation, opthalmoplegia, confusion
  • damaged mamillary bodies