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0. Step Ia > Biochem - Nutrition/Vitamins > Flashcards

Biochem - Nutrition/Vitamins Flashcards

1
Q

Vitamin B1 function

A

THIAMINE cofactor in

  • Pyruvate dehydrogenase (links glycolysis to TCA cycle)
  • α-ketoglutarate dehydrogenase (TCA cycle)
  • Transketolase (HMP shunt)
  • Branched-chain ketoacid dehydrogenaseATP
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1
Q

confusion, ophthalmoplegia, ataxia

A

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)

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1
Q

Dermatitis, enteritis, alopecia, adrenal insufficiency.

A

B5 is “pento”thenate

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1
Q

cobalamin deficiency can cause these 4 sx:

A
  • Macrocytic, megaloblastic anemia
  • hypersegmented PMNs
  • paresthesias
  • subacute combined degeneration of dorsal columns, lateral corticospinal tracts, and spinocerebellar tracts) due to abnormal myelin.
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2
Q

Marasmus

A

energy malnutrition, muscle wasting

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3
Q

outcomes of Vitamin A deficiency 5

A
  • Night blindness (nyctalopia)
  • dry, scaly skin (xerosis cutis)
  • alopecia
  • corneal degeneration (keratomalacia)
  • immune suppression.
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4
Q

polyneuritis, symmetrical muscle wasting.

A

Dry Beriberi, Thiamine deficiency

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4
Q

pathophysiology of giving glucose to a vitamin B1 deficient patient

A

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!

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5
Q

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

A

B6 (pyridoxine)

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6
Q

3 supplements you must give to a breast-fed neonate

A

1) vitamin D - promote intestinal absorption of Ca and bone mineralization
2) Vitamin K - prevent bleeding diathesis
3) Fe (prevent IDA)

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7
Q

vitamin B12 (cobalamin)

function?

outcomes of deficiency?

possible causes of deficiency?

diagnosed by?

A
  • 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
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7
Q

vitamin E

function

how deficiency presents

A

fat-soluble

function: antioxidant for erythrocytes
deficiency: hemolytic anemia, neuropathy

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7
Q

wet beriberi

A

high-output cardiac failure due to thiamine deficiency

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7
Q

thiamine - which vitamin?

A

B1

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7
Q

Vitamin B1 deficiency

A

Wernicke-Korsakoff syndrome and beriberi (Ber1Ber1)

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7
Q

treatment of cobalamin deficiency with folic acid results in

A

subacute combined degeneration of dorsal columns.

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7
Q

causes of calcium oxalate nephrolithiasis?

common presentation?

trmt?

A

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.

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8
Q

Folate - which vitamin?

A

B9

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9
Q

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

A

B6 ∆

Convulsions

Hyperirritability

Peripheral neuropathy

Sideroblastic anemias (impaired hemoglobin synthesis and iron excess)

B3 deficiency -> pellagra

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10
Q

zinc

function?

deficiency?

A

function: widespread, transcription factors
deficiency: metallic taste, delayed wound healing, hypogonadism, acrodermatitis enteropathica

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10
Q

Niacin is used to treat:

A

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

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10
Q

storage pool of folic acid vs storage pool of cobalamin?

A

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

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

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11
Q

Vitamin A excess - 6

A
  • Teratogen
  • Skin ∆s (scaliness)
  • alopecia
  • cerebral edema “pseudotumor cerebri”
  • osteoporosis
  • hepatic abnormalities
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11
Q

Diarrhea

Dementia (also hallucinations)

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

A

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

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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
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
19
3 causes of vitamin K deficiency:
* warfarin * neonates (sterile intestines - remember Vit K is made by intestinal flora) * Antibiotic use (kills off intestinal flora)
19
Total calorie malnutrition resulting in tissue and muscle wasting, loss of subcutaneous fat, and variable edema.
Marasmus = Muscle wasting.
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
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).
27
Essential component of coenzyme A and fatty acid synthase.
Vitamin B5 (pantothenate)
27
Hemolytic anemia, acanthocytosis, muscle weakness, posterior column and spinocerebellar tract demyelination.
Vitamin E deficiency (tocopherol/tocotrienol)
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
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)
35
high-output cardiac failure (dilated cardiomyopathy), edema.
Wet beriberi due to thiamine B1 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
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).
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
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)
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
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
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
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.
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
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

0. Step Ia (28 decks)

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