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Step Review Things to Memorize > Vitamins > Flashcards

Vitamins Flashcards

1
Q

Vitamin A function

A

Antioxidant
Part of visual pigment retinal
Differentiation of epithelial cells (pancreatic cc or mucus-secreting cc)
Prevents squamous metaplasia
Treat measles and acute promyelocytic leukemia

Topical tx for wrinkles and acne
Found in liver and leafy veggies
PO isotretinoin for severe cystic acne
ATRA for APML

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2
Q

Vitamin A deficiency

A

Night blindness (nyctalopia); dry, scaly skin (xerosis cutis), corneal degeneration (keratomalacia), bitot spots on conjunctiva, immunosuppression

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3
Q

Vitamin A toxicity

A

Acute: nausea/vomiting, vertigo, blurred vision

Chronic: alopecia, dry skin, hepatotoxicity and enlargement, arthralgias, pseudotumor cerebri

Teratogen: cleft palate/ cardiac abnormalities; required pregnancy test before isotretinoin Rx

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4
Q

Vitamin B1 (thiamine) function

A

A part of thiamine pyrophosphate (TPP), a cofactor for:
Pyruvate dehydrogenase (links glycolysis to TCA cycle)
alpha-ketoglutarate dehydrogenase (TCA cycle)
Transketolase (HMP shunt)
Branch-chain ketoacid dehydrogenase

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5
Q

Vitamin B1 (thiamine) deficiency

A

Impaired glucose breakdown, low ATP worsened by glucose infusion, aerobic tissue affected first

In alcoholic patients gives thiamine before dextrose to stop precipitating Wernicke’s encephalophathy

Dg: increased transketolase activity in RBCs post B1 administration

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6
Q

Vitamin B1 (thiamine) diseases

A

Wernicke-Korsakoff syndrome: confusion, ophthalmoplegia, ataxia with confabulation, personality changes, damage to medial dorsal nucleus of thalamus, mammillary bodies

Dry beriberi- polyneuritis and symmetrical muscle wasting

Wet beriberi- HFpEF (DCM), edema

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7
Q

Vitamin B2 (riboflavin) function

A

Part of flavins (FAD and FMN) cofactors in redox reactions (eg succinate dehydrogenase in TCA cycle)

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8
Q

Vitamin B2 (riboflavin) deficiency

A

Cheilosis (inflammation of lips, scaling and fissures at corners of mouth), corneal vascularization

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9
Q

Vitamin B3 (niacin) function

A

Part of NAD+, NADP+ (redox), derived from tryptophan and synthesis requires B2 and B6

Treats dyslipidemia: lowers VLDL and raises HDL

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10
Q

Vitamin B3 (niacin) deficiency

A

Glossitis
Severe leads to pellagra (can also be caused by Hartnup disease, malignant carcinoid sy (increased tryptophan metabolism) and isoniazid (decreased B6))
Pellagra: diarrhea, dementia, dermatitis (dermatomal), hyperpigmentation of exposed skin

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11
Q

Vitamin B3 (niacin) deficiency- Hartnup disease

A

AR deficiency of neutral amino acid transporters in PCT and on enterocytes (neutral aminoaciduria) so less tryptophan for conversion to niacin
Tx: high protein diet, and nicotinic acid

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12
Q

Vitamin B3 (niacin) excess

A

Facial flushing (PGs) avoid by taking ASA with niacin, hyperglycemia, hyperuricemia

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13
Q

Vitamin B5 (pantothenic acid) function

A

Essential for CoA (acyl transfers) and fatty acid synthase

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14
Q

Vitamin B5 (pantothenic acid) deficiency

A

Dermatitis, enteritis, alopecia, adrenal insuff.

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15
Q

Vitamin B6 (pyridoxine) function

A

Converted to pyridoxal phosphate (PLP) cofactor in transamination (ALT and AST), decarboxylaton, glycogen phosphorylase
Needed to make: cystathionine, heme, niacin, histamine, NTs (serotonin, epi, norepi, DA and GABA)

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16
Q

Vitamin B6 (pyridoxine) deficiency

A

Convulsions, irritability, peripheral neuropathy (inducible by iNH and OCPs), sideroblasitic anemia due to impaired Hgb synth and iron excess

17
Q

Vitamin B7 (biotin) function

A 
Cofactor for carboxylation (add 1C)
Pyruvate carboxylase (pyruvate to oxaloacetate)
AcetylCoA carboxylase (acetylCoA to malonyl CoA)
PropionylCoA carboxylase (PropionylCoA to methylmalonylCoA)

Avidin in eggwhites can bind biotin and cause deficiency

18
Q

Vitamin B7 (biotin) deficiency

A

Dermatitis, alopecia, enteritis

Caused by Abx or eggwhites

19
Q

Vitamin B9 (folate) function

A

Converted to THF (coenzyme for 1-carbon transfer/methylation reactions)
Synthesis of nitrogenous vases for DNA and RNA
Found in leafy green veggies, absorbed in jejunum, stored in liver

20
Q

Vitamin B9 (folate) deficiency

A

Macrocytic megaloblastic anemia; hypersegmented PMNs, glossitis, NO NEURO

Labs: elevated homocysteine, nl methylmalonic acid
Assoc with alcoholism in pregnancy

Drugs can cause: phenytoin, sulfonamides, methotrexate
Supplement at least 1 mo prior to conception and during preg to prevent neural tube defects

21
Q

Vitamin B12 (cobalamin) function

A

Cofactor for methionine synthase (transfers methyl group as methycobalamin) AND methylmalonyl-CoA mutase. Important in DNA synthesis.

Found in animal products, reserve for years in liver

22
Q

Vitamin B12 (cobalamin) deficiency

A

Macrocytic megaloblastic anemia; hypersegmented PMNs, glossitis, paresthesias, subacute combined degeneration (dorsal columns, lateral corticospinal tracts and spinocerebellar tracts) due to abnl myelin; can lead to irrev. nerve damage

Causes: malabsorption (ileum) from sprue, enteritis, tape worm, lack of IF (bypass, pernicious anemia), lack of ileum (surgery, CD), veganism

Labs: elevated homocysteine, methylmalonic acid and 2˚ folate deficiency

23
Q

Vitamin C (ascorbic acid) function

A

Antioxidant; facilitates Fe absorption by reducing to Fe2+; necessary for hydroxylation of pro and lys residues in preprocollagen; necessary for dopamine-beta-hydroxylase which converts DA to NE

Found in fruits and veggies

Ancillary tx for methemoglobinemia for reducing Fe to Fe2+

24
Q

Vitamin C (ascorbic acid) deficiency

A

Scurvy- swollen gums, bruising, petechiae, hemarthrosis, anemia, poor wound healing, perifollicular and subperiosteal hemorrhages, corckscrew hair
Weakened immune response

25
Q

Vitamin C (ascorbic acid) excess

A

Nausea, vomiting, diarrhea, fatigue, Ca oxalate stones, increased risk of iron tox. in transfused or ppl with hemochromatosis

26
Q

Vitamin D forms

A

D2- ergocalciferol- ingested from plants
D3- cholecalciferol- consumed in milk, formed in sun exposed stratum basale
25-OH D3 - storage form
1,25-(OH)2D3 - calcitriol (active form)

27
Q

Vitamin D function

A

Intestinal absorption of Ca and phosphate, increased bone mineralization at low levels, bone resorption at high levels

28
Q

Vitamin D deficiency

A

Rickets in kids (varum bow legs); osteomalacia in adults (bone pain and muscle weakness), hypocalcemic tetany; breastfed infants need oral vit D. Deficiency is exacerbated by sun exposure, pigmented skin, prematurity

29
Q

Vitamin D excess

A

Hypercalcemia, hypercalciuria, loss of appetite, stupor

Seen in granulomatous disease (increased D activation by epithelioid histocytes)

30
Q

Vitamin E (tocopherol/tocotrienol) function

A

Antioxidant- protects RBC and membranes from free radical damage
HD supplementation may alter vitamin K metabolism to enhance warfarin anticoagulation

31
Q

Vitamin E (tocopherol/tocotrienol) deficiency

A

Hemolytic anemia, acanthoytosis, muscle weakness, posterior column and spinocerebellar tract demyelination

May look like B12 deficiency; without megaloblastic anemia or hypersegmented neutrophils or methylmalonic acid

32
Q

Vitamin K (phytomenadione, phylloquinone, phytonadione) function

A

Activated by epoxide reductase to reduced form which is a cofactor for gamma-carboxylation of glutamic acid residues on factors II, VII, IX and X + proteins C and S

Found in plants

Warfarin inhibits K-dep synth of above factors

33
Q

Vitamin K (phytomenadione, phylloquinone, phytonadione) deficiency

A

Neonatal hemorrhage with elevated PT and aPTT; nl bleeding time, because can’t synth K due to sterile intestines; also post-prolonged Abx

Not in breast milk, give vit. K injection at birth

34
Q

Zinc function

A

essential for many enzymes especially transcription factors

35
Q

Zink deficiency

A

Delayed would healing, hypogonadism, lose of adult hair, dysgeusia, anosmia, acrodermatits enteropathica; predispose to alcoholic cirrhosis

Step Review Things to Memorize (41 decks)

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