Uworld 7 Flashcards

1
Q

What does IL-12 do?

A

stimulates the differentiation of “naive” T helper cells into the Th1 subpopulation

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2
Q

rickets bones look like what?

A

excess of unmineralized osteoid matrix and epiphyseal (growth plate) cartilage

Low vitamin D leads to hypocalcemia and/or hypophosphatemia due to reduced intestinal absorption of these minerals; PTH is markedly elevated to mobilize calcium from bone to the bloodstream

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3
Q

2month old - initially no ssx; then impaired metabolism, slowing of physical and mental activity (lethargy, poor feeding, constipation, hypotonia)

non-pitting edema (puffy face), umbilical hernia, protruding tongue, and a large anterior fontanelle

A

congenital hypothyroidism

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4
Q

dystrophic calcification is considered a hallmark of

A

cell injury and death, occurring in all types of necrosis in the setting of normal calcium levels

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5
Q

bacterial mRNA can be polycistronic, meaning that…

what is an example

A

one mRNA codes for several proteins

bacterial lac operon, which codes for the proteins necessary for lactose metabolism by E. coli; the transcription and translation of these bacterial proteins is regulated by a single promoter, operator, and set of regulatory elements

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6
Q

What antiarrhythmic has less of a chance of inducing torsades while prolonging the QT interval?

A

amiodarone

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7
Q

What is the MC cardiac defect in pts with down syndrome?

A

complete atrioventricular (AV) canal defect

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8
Q

mutations in frataxin, a mitochondrial protein important in iron homeostasis and respiratory function cause

A

Friedreich ataxia

spinocerebellar degeneration and is associated with hypertrophic cardiomyopathy

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9
Q

What five receptors regulate vomiting reflex?

Which ones are targets for reducing N/V in chemo?

A
  1. M1 muscarinic
  2. D2 dopaminergic
  3. H1 histamine

targets in chemo pts:

  1. 5-HT3 serotonergic
  2. neurokinin 1 (NK1)
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10
Q

a false aneurysm or pseudoaneurysm is…

A

result of a breach in the continuity of all 3 layers of a blood vessel (or heart), leading to blood leakage and hematoma formation outside the vascular wall; resulting hematoma is then contained within a sac of connective tissue surrounding the original point of arterial wall rupture

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11
Q

medial degeneration is characterized by …

A

the fragmentation of elastic tissue (basket weave pattern) and separation of the elastic and fibromuscular components of teh tunica media by small, cleft-like spaces that become filled with amorphous extracellular matrix

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12
Q

what is the most common trigger for paroxysmal AF?

A

aberrant electrical foci in the pulmonary veins near their ostia into the left atrium

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13
Q

What cells are seen in follicular lymphoma?

What translocation is commonly seen?

A

predominantly centrocytes (small cleaved cells) and fewer numbers of centroblasts (large noncleaved cells)

t(14:18) resulting in overexpression of bcl-2

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14
Q

CK release is related to what?

A

reperfusion injury - secondary to oxygen free radical generation, mitochondrial damge, and inflammtion - resulting in cell membrane damage, allowing creatine kinase to leak out of the cell

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15
Q

during the first few weeks of embryogenesis, hemoglobin is synthesized by the yolk sac and contains…

A

zeta or epsilon globin chains

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16
Q

HbF production begins at … weeks and replaces all embryonic Hb by…. weeks

A

8 weeks

14 weeks

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17
Q

sorbitol dehydrogenase converts sorbitol into

A

fructose

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18
Q

What are the two most important acid buffers in urine?

A

HPO4 ^2- and NH3

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19
Q

what are features of atypical MDD and what might be a drug to treat this?

A

increased appetite and sleep, leaden paralysis, rejection sensitivity, and mood reactivity

MAO-I like phenelzine or tranylcypromine

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20
Q

What does neprilysin do?

Why would you rx a neprilysin inhibitor in heart failure?

A

is a metalloprotease that cleaves and inactivates ANP and BNP

this would lead to increased levels of ANP and BNP and promote beneficial effects in heart failure - increasing urinary sodium excretion

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21
Q

Why does someone with sarcoid have hypercalcemia?

A

1-alpha hydroxylase expression in activated macrophages in the lung and lymph nodes causes PTH-independent production of 1,25-dihydroxyvitamin D

increased intestinal absorption of calcium and subsequent hypercalcemia

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22
Q

What interleukins play an active role in the pathogenesis of psoriasis?

A

IL-12 and IL-23

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23
Q

H. pylori in the gastric antrum will cause…

H. pylori in the gastric corpus/body will cause…

Unlike antral-predominant disease, coprus predominant disease is a/w….

A

duodenal ulcers

gastric ulcers

metaplasia and malignancies (eg gastric lymphoma, adenocarcinoma)

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24
Q

renal biopsy showing rounded/polygonal cells with abundant clear cytoplasm which is characteristic of…

where does this originate?

A

renal clear cell carcinoma (MC form)

originates from proximal tubular epithelial cells

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25
Q

paroxysmal nocturnal hemoglobinuria is usually due to what mutated gene?

what does this gene normally do?

what does this protein do?

What happens without it?

A

phosphatidylinositol glycan class A (PIGA) gene

helps synthesize the glycosylphosphatidylinositol (GPI) anchor protein

this protein helps attach several cell surface proteins (eg CD55 decay accelerating factor, CD59 MAC inhibitory protein) that inactivate complement

without, there is uncontrolled complement-mediated hemolysis

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26
Q

single most important risk factor for the development of intimal tears leading to aortic dissection?

A

hypertension

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27
Q

What is Buerger disease?

A

thromboangiitis obliterans, a vasculitis of medium and small arteries, principally the tibial and radial arteries

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28
Q

What are the predominant cells found in granulomas?

A

epitheliod histiocytes and multinucleated Langhans giant cells

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29
Q

What is the essential amino acid for pts with PKU? Why?

A

tyrosine

they have an inability to convert phenylalanine to tyrosine by the phenylalanine hydroxylase system

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30
Q

low serum levels of C1 esterase inhibitor are diagnostic of…

what is the pathophys behind this?

A

hereditary angioedema

C1 esterase inhibitor suppresses activation of C1 complement component and therefore the rest of the classic complement pathway;

it also inactivates kallikrein, which catalyzes the conversion of kininogen to bradykinin; in hereditary angioedema, activate kallikrein and bradykinin levels are increased;

Bradykinin, C3a, and C5a mediate angioedema by increasing vasodilation and vascular permeability

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31
Q

What part of complement will be low in C1 esterase inhibitor deficiency?

A

C4

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32
Q

What drugs are CI in C1 esterase inhibitor deficiency?

A

ACE inhibitors

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33
Q

The sciatic foramen is divided into greater and lesser sciatic foramina by what ligament?

A

sacrospinous ligament

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34
Q

What structures run above and below the piriformis through the greater sciatic foramen?

A
  • above the piriformis
    • superior gluteal vessels
    • superior gluteal nerve
  • below the piriformis
    • inferior gluteal vessels
    • internal pudendal vessels
    • multiple nerves, including sciatic
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35
Q

PNH is caused by an acquired mutation of the PIGA gene within clonal population of multipotent hematopoietic stem cells. This gene is involved in the synthesis of the….

What is the importance of this?

A

glycosylphosphatidylinositol (GPI) anchor

a glycolipid necessary for the attachment of several cell surface proteins, including CD55 (decay accelerating factor) and CD59 (MAC inhibitory protein)

these proteins help inactivate complement and prevent the membrane attack complex from forming on normal cells

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36
Q

Absence of GPI anchor results in CD55 and CD59 deficiency and ….

when does this occur?

A

complement mediated hemolysis

more often at night because complement activity is increased during sleep to lower blood pH

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37
Q

histologically, what does silicosis appear as?

A

birefringent silicate particles within dense, whorled collagenous nodules surrounded by dust-laden macrophages

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38
Q

What does silicosis look like on XR?

A

numerous small, rounded nodules predominant in upper lobes; calcification of the rim of hilar nodes (eggshell calcification) may also be seen

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39
Q

What is the MC extraintestinal manifestation of Entamoeba histolytica infection?

What is common with invasive strains?

A

single amebic liver absecess in the R lobe of the liver

invasive strains are more likely to have amebic proteases that degrade host extracellular membranes and secretory IgA

also demonstrate contact-dependent cytotoxicity, whereby an amebic lectin binds the host cell, introduces an amebic porin into the host cell membrane and causes cell lysis

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40
Q

RBC fragments, burr cells and helmet cells are consistent with…

What is this a result of?

A

traumatic hemolysis

either microangiopathic hemolytic anemia or mechanical damage (eg prosthetic valve)

41
Q

How does Shigella invade the GI mucosa?

How does it cause damage?

A

gains access to microfold cells in ileal Peyer patches through endocytosis

then it lyses the endosome and spreads laterally into other epithelial cells, causing cell death and ulceration wiht hemorrhage and diarrhea

42
Q

What is the MC GI disorder in pts with CF?

How does this occur?

A

pancreatic insufficiency

mutations in CFTR gene lead to thick, viscous secretions in the lumens of the pancreas, resulting in obstruction, inflammation, and subsequent fibrosis

clinical - steatorrhea, failure to thrive, and deficiency of fat-soluble vitamins

43
Q

What does dobutamine do on the heart?

A

mimics the effects of exercise and increases myocardial oxygen demand

used during stress testing to provoke areas of ischemic myocardium, which can be recognized on imaging by a localized and transient decrease in contractility (ie wall motion defect)

44
Q

blistering skin rash in young children with tan- to honey-colored crusts;

dx?

what causes this blistering?

A

Bullous impetigo - S. aureus

caused by exfoliative toxin A, which targets desmoglein 1 in epidermal cellular junctions and causes a loss of cell adhesion

45
Q

thin, myelinated nerve fibers whose free nerve endings detect temperature and nociceptive stimuli; associated with acute (sharp) pain and constitute the afferent portion of the reflex arc that mediates withdrawal from noxious stimuli

A

A-delta fibers

46
Q

Both Pacinian corpuscles and Ruffini’s end organs are innervated by

A

myelinated A-beta fibers

47
Q

Adverse effect of oxygen therapy in neonate?

A

retinal damage

temporary local hyperoxia in the retina is thought to induce changes that cause up-regulation of proangiogenic factors such as VEGF upon return to room air ventilation - can result in neovascularization and possible retinal detachment with blindness may result

aka retinopathy of prematurity or retrolental fibroplasia

48
Q

the toxicity of cyanide is dependent on its ability to bind

A

ferric iron (Fe3+) with high affinity, inhibiting cytochrome c oxidase in the mitochondria

49
Q

lab studies in cyanide poisoning show…

A

severe lactic acidosis in conjunction with a narrowing of the venous-arterial PO2 gradient, resulting from the inability of tissue to extract arterial oxygen

50
Q

How do you treat cyanide poisoning?

A

admin of inhaled amyl nitrite which oxidizes ferrous iron (Fe2+) present in hemoglobin to ferric iron (Fe3+), generating methemoglobin

incapable of carrying oxygen but has high affinity for cyanide; binds and sequesters cyanide in the blood, freeing it from cytochrome oxidase and limiting its toxic effects

hydroxycobalamin (Vit B precursor) and sodium thiosulfate are also antidoes for cyanide poisoning

51
Q

livedo reticularis, a blue toe, and acute kidney injury following coronary angiography

dx?

what is happening if invasive vascular procedures are preceding these events?

A

atheroembolic disease

can cause cholesterol containing debris from plaques to become dislodged from large arteries and show microemboli into circulation

52
Q

What happens in systemic mastocytosis?

What are mutations often associated?

What are ssx?

A

clonal mast cell proliferation occurs in the bone marrow, skin and other organs

a/w mutations in the KIT receptor tyrosine kinase

cells are characterized by promient expression of mast cell tryptase; excessive histamine release mediates symptoms of syncope, flushing, hypotension, pruritis, and urticara (can also induce gastric acid secretions, leading to ulceration)

53
Q

Tx for PCOS

A

advised on weight loss

OCPs if not wanting to be pregnant, to minimize endometrial proliferation, reduce androgenic symptoms

clomiphene or letrozole to induce ovulation if trying to become pregnant; clomiphene is a SERM that prevents negative FB inhibition on the HT and pituitary by circulating estrogen, resulting in increased FSH and LH production

54
Q

What is the major cause of morbidity and mortality from theophylline intoxication?

A

seizures

tachyarrhythmias are other major concern

55
Q

how do you treat theophylline intoxication?

A

admin of activated charcoal to reduce GI absorption

beta blockers for theophylline induced tachyarrhythmias

benzos and barbituates most effective against seizures

56
Q

What upper midbrain structures mediate the direct and consensual pupillary light reflex?

A

optic nerve, pretectal nuclei, Edinger-Westphal nuclei, oculomotor nerve

57
Q

What part of the spine will RA affect?

A

cervical spine

58
Q

poison ivy reaction is mediated by what cells?

A

T cells; Type IV hypersensitivity reaction

59
Q

in chronic heart failure, what initially offsets factors favoring edema?

A

increased lymphatic drainage

60
Q

budding yeast with thick capsules - etiology?

what does this most commonly cause?

A

cryptococcus neoformans

meningoencephalitis is MC presentation; occurs in immunosuppressed pts and diagnosed by india ink staining of CSF;

cryptococcal pna dx’d by mucicarmine staining of lung tissue and bronchoalveolar washings

61
Q

Reverse transcriptase polymerase chain reaction (RT-PCR) is used to detect and quantify levels of…

How would it be used to dx CML?

A

mRNA in a sample

by identifying an mRNA transcript containing both BCR and ABL exons in affected cells

62
Q

In osteogenesis imperfecta, the defect in type 1 collagen results in impairment of what process?

A

osteoid production by osteoblasts

63
Q

neurodegenerative disorder caused by accumulation of abnormally folded protein within the brain

A

Prio disease

64
Q

What structure do prions normally exist in?

When does prion disease occur?

A

alpha-helical structure (PrP^c)

Prion disease occurs after a domain in this protein undergoes a conformation change from an alpha helix into beta-pleated sheet isoform (PrP^sc [scrapie]), which confers the ability to induce similar conformational changes in other proteins

65
Q

What are qualities of the beta pleated sheets in prion disease?

A

resistant to proteases and forms long, highly neurotoxic fibrils, which accumulate intracellularly in neurons and form extracellular deposits

66
Q

Why is there high chloride content in RBCs in venous blood?

A

CO2 is transported to lungs as bicarb

within RBCs, carbonic anhydrase forms bicarb from CO2 and water

excess bicarb is then transferred out of RBCs into the plasma via exchange with chloride ions

this exchange is known as “chloride shift”

67
Q

What happens with pyruvate kinase deficiency?

A

causes hemolytic anemia due to failure of glycolysis and resultant failure to generate sufficient ATP to maintain erythrocyte structure

68
Q

drugs that improve long term survival in patients with systolic HF

A

ACE-Is, AT II receptor blockers, aldosterone antagonists, beta blockers

69
Q

What does isoproterenol do?

A

can mediate vasodilation via Beta2 receptors, particularly in striated muscle, renal, and mesenteric vascular beds, leading to decreased peripheral resistance with increased cardiac output

70
Q

small and cuboidal in shape, grow in cords or sheets, and form follicle- or rosette-like structures (Call Exner bodies) that have a gland-like appearacne with a pink eosinophilic center and coffee bean nuclei

this is the histology consistent with…

what does this tumor secrete?

A

granulosa cell tumor

secretes estrogen

71
Q

loss of palpable pulse during inspiration

A

pulsus paradoxus

cardiac tamponade

72
Q

What factors inhibit renal calculi formation?

A

increased urinary citrate and high fluid intake

73
Q

Epidermal growth factor receptor gene mutations are present in some …

A

non-small cell lung cancers, most commonly adenocarcinoma in nonsmokers

74
Q

necolytic migratory erythema, an elevated painful and pruritic rash typically affecting the face, groin, and extremities; over time, small erythematous papules coalesce to form large, indurated plaques with a central clearing that often appears brown or bronze colored

dx?

A

glucagonoma

75
Q

zinc deficiency mainly causes

A

erythematous skin lesions (mainly around body orifices) that are predominantly vesicular and pustular

other features include hypogonadism, impaired taste and smell, night blindness, and impaired wound healing

76
Q

Pts with what IBD are more prone to developing fistulas/abscesses?

A

Crohn Disease

77
Q

Activating mutations of KRAS gene lead to constitutive activation of

A

the EGFR pathway, promoting increased cell proliferation and growth

78
Q

synchronization of glycogen degradation with skeletal muscle contraction occurs due to the release of

A

sarcoplasmic calcium following neuromuscular stimulation; increased intracellular calcium causes activation of phosphorylase kinase, stimulating glycogen phosphorylase to increase glycogenolysis

79
Q

finely granular, diffusely homogeneous, pale eosinophilic cytoplasm (ground glass hepatocytes) are found in

A

hepatitis B infection

80
Q

lymphoid aggregates within the portal tracts and focal areas of macrovesicular steatosis is seen in

A

hepatitis C infection

81
Q

drug of choice for tx’ing bulemia nervosa

A

fluoxetine SSRI

82
Q

urine leakage with coughing, lifting, or sneezing is going to be due to..

A

decreased urethral sphincter tone or urethral hypermobility

83
Q

sudden overwhelming urge to urinate is a/w what dysfunction?

A

detrusor hyperactivity

84
Q

What does phenylephrine do?

A

alpha 1 agonist that increases peripheral vascular resistance and systolic BP and decreases pulse pressure and HR

85
Q

Polyarteritis nodosa (PAN) is a multisystem vasculitis characterized by episodic ischemic symptoms in various organs with sparing of the lungs; it is commonly associated with

A

Hepatitis B

86
Q

Virtually all pts with polycythemia vera have a mutation in

A

JAK2, a non-receptor (cytoplasmic) tyrosine kinase associated with the erythropoietin receptor

87
Q

What cells do infected macrophages with TB trigger?

A

triggers CD4 T lymphocytes to release IFNy, which leads to macrophage activation (improves intracellular killing ability) and differentiation into epithelioid histiocytes

88
Q

child with proteinuria, hypoalbuminermia, and edema that are reversible with corticosteroids

dx?

A

minimal change disease

89
Q

adult, severe coughing spells with vomiting occasionally, hasn’t seen a doc in years, clear CXR

dx

etiology

A

Pertussis

gram negative coccobacillus

90
Q

Where are aconitase and enolase enzymes?

A
  • aconitase is in the Krebs cycle, catalyzing the isomerization of citrate to isocitrate
  • enolase is in glycolysis, catalyzing the conversion of 2-phosphoglycerate to phosphoenolpyruvate
91
Q

In the absence of ADH, where is tubular fluid most concentrated?

A

most concentrated at the junction between the descending and ascendinng limbs of the loop of Henle and most dilute in the collecting tubules

92
Q

what is the MC risk factor for calcium stones in adults?

A

hypercalciuria (most cases idiopathic)

pt will still be normocalcemia

93
Q

infected fetus has severe anemia, heart failure, pleural effusions, pericardial effusions, and ascites

A

hydrops fetalis - probs from parvovirus infection

94
Q

Where do NSAIDs affect the kidney?

A

they inhibit prostaglandin production which normally help maintain renal production by dilating the afferent arteriole, particularly in pts with intravascular volume depletion or CKD

inhibition of afferent dilation with NSAIDs results in reduced glomerular filtration and prerenal azotemia with elevations in creatinine and BUN (ratio >20:1)

95
Q

What are the near-immediate effects of an ACE-I in someone with bilateral renal artery stenosis?

A
  • lower AT II
    • reducing systemic pressures and relative dilation of the efferent arteriole
  • if bilateral RAS
    • systemic pressure no longer high enough to overcome stenosis and renal blood flow drops
    • dilation of efferent arteriole leads to a reduction of intraglomerular filtration pressure, which results in the reduction of GFR and filtration fraction
96
Q

When would I see acanthocytes and how do they appear?

A

irregularly spced surface projections that vary in length and width

spur cells are the extreme form

typical of abetalipoproteinemia

97
Q

When would you see spherocytes?

A

hereditary spherocytosis, autoimmune hemolytic anemia, burns, and blood samples that are not fresh

98
Q

When do you see teardrop cells?

A

myelofibrosis

99
Q

What are the G protein coupled receptors on pancreatic beta cells and what do they do?

A
  • M3/Gq, Glucagon/Gs/q, B2/Gs, GLP-1/Gs
    • increase insulin secretion
  • A2 and somatostatin 2 Gi
    • decrease insulin secretion