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Flashcards in usmle2: block 3 Deck (67)
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1
Q

most common cause of epididymitis in heterosexual male

A

c. trachomatis

homosexual: colon bacterias

2
Q

what drug can be given w/ penicillin to inhibit metabolism / secretion

A

penicillin + probenicid

prevents reabsorption of uric acid
prevents secretion of penicillin

3
Q

bloom syndrome

A

photosensitivty, short stature, erythema, teleangiectasia

defect in DNA helicase RecQL3

predisposed to lymphoproliferative & GI malginancy

4
Q

where does heriditary nonpolyposis colon cancer usu arise

A

microsatellite instability
mismatch repair defect

usu proximal bowel

5
Q

waxing & waning lymphadenopathy

A

follicular lymphoma
bcl-2 t(14,18)

small cleave w/o nucleoli &
large cell w/ mult nucleoli

6
Q

burkitt lymphoma in industrialized country location

A

ascites & abdominal mass

distal ileum, cecum, mesentary

7
Q

Dupuytren’s contractures

A

fixed flexion of fingers

physical manifestation of high estrogen in cirrhotic patients

8
Q

what are lisch nodules

A

pigmented iris hamartomas

9
Q

what’s in a neurofibroma

A

schwann cells, fibroblasts, neurites

10
Q

niacin mechanism

A

block hormone sensitive lipase –> reduce formation of VLDL and triglyerides

increases HDL
decrease TG

11
Q

possible niacin side effects

A

prostaglandin mediated:

flushing, pruitis, headache

12
Q

how many of the oocytes we are born w/ remain at puberty?

A

25%
of that, only 400 will be ovulated normally
rest = atesia

13
Q

describe follicular atresia (oocytes)

A

outside basal lamina: THECA cells dedifferentiate & return to poor of ovarian interstitial or stromal cells

in basal lamia: OOCYTE & GRANULOSA cells = apoptosis

14
Q

which antibiotics are teratogen (2)

A

aminoglycoside “a mean guy hit the baby” CN VIII toxicity

tetracycline: discolored teeth

15
Q

which antiseizure drugs are teratogen (3)

A

carbamazepine, phenytoin, valproate (inhibit folate reabsporption

PVC

16
Q

which anti-thyroid drug is a teratogen

A

methimazole

17
Q

loss of heterozygosity

A

relevant to oncogenesis

person born w/ single defective copy of tumor supressor gene does not develop malignancy until some cells spontaneously mutate other gene

18
Q

reason diff alleles have different cuts on restriction enzyme digestion?

A

single nucleotide polymorphisms at restriction enzyme cleavage site

19
Q

how does paclitaxel in a drug-eluting stent work?

A

prevents intimal hyperplasia

major cause of restenosis

20
Q

after placing a coronary stent, what is the major cause of restenosis?

A

intimal hyperplasia
prevent w/ paclitaxel / sirolimus
freeze cells in metaphase

21
Q

anti-platelets post stent?

A

given LONGER w/ drug-eluting stents (paclitaxel) bc the rate of endolthelium reformation delayed.

less time w/ bare metal stents

22
Q

which RNA viruses replicate in nucleus?

A
  • retroviruses (HIV, HTLV)

- influenza

23
Q

where does influenza replicate

A

nucleus! (+ HIV) all other rna virus = cytoplasm

24
Q

most common cause of pneumonia in infant

A

RSV

25
Q

croup & bronchiolitis in children

bronchitis in adult

A

parainfluenza birus

26
Q

which GLUT is insulin dependent? which tissues

A

GLUT 4: muscle & adipocytes

27
Q

what 2 muscles pull on acromial-end of clavicle? medial portion (3)

A

lateral:

  1. deltoid
  2. trapezius

medial

  1. pec major
  2. sternocleidomastoid
  3. sternohyoid
28
Q

Ras is downstream

A

GTP-binding protein
downstream RTK
-single transmembrane, dimerize on binding

(not GPCRs)

29
Q

differential of orotic aciduria?

A
  1. if also hyperammonia: OTC
    build up of carbamoyl phosphate –> shunt to de novo pyridamine synthesis –> orotic acid temp base
  2. w/o hyperammonia –> orotic aciduria
30
Q

steps of collagen formation

A
in ER:
hydroxylation of proline/lysine
glycosylation of some lysine
assembly of triple helix = PROCOLLAGEN
--requires 1. H bonding of hydroxylated groups & 2. disulfide bonding w/ C-terminals

secrete procollagen into golgi -> out of cell

in ECM
cleave N & C terminus -> collagen fibril
crosslink via lysyl oxidase

31
Q

most common amino acid in collagen

A

glycine

Gly-X-Y (other: proline, lysine)

32
Q

absence of proline hydroxylation results in

A

cannot form pro-collagen in ER bc triple-helix will be abnormal.

33
Q

what is procollagen

A

formed in ER

-triple helix (thanks to hydroxylation of proline/lysine) and disulfide bonds of C terminal groups

ultimately secreted by cell

34
Q

presentation of transtentorial herniation

A

uncal
-fixed and dilated pupil on ipsilateral side
-can produce ipsilateral or contralateral hemiparesis (cerebral peduncle)
(compress external parasympathetics)

ipsilateral hemiparesis: kernohan phenomenon
- due to shifting of entire brainstem, compresses contralateral cerebral peduncle against rim of tentorium

35
Q

MLF

A

links nuclei of CN VIII proprioception from inner ear w/ nuclei for eye movements

also allows for conjugate lateral gaze, communication between

also: CNVI and CNIII nuclei

when CNVI nucleus activates lateral rectus, will also activate CNIII for medial rectus –> conjugate movement

damaged in multiple sclerosis

36
Q

internuclear opthalmoplegia

A

lesion to MLF
problem w/ conjugate lateral gaze

CNVI nuclei fails to tell contralateral CNIII to contract medial rectus (while telling ipsilateral lateral rectus)

will see nystagmus in abducting eye (overstimulation by CN VI)

37
Q

conversion

A

conversion: symptoms unexplained by medical condition. preceeded by psychological stressor

not intentionally produced; cause impairment of normal fxn.

38
Q

somatizatin disorder

A

multiple physical complaints before age 30

  • 4 pain symptoms: 2 GI, one sex, one neuro
  • unexplained by general medical condition
  • not artificially produced
  • causing significant impairment
39
Q

what neurological disease makes a protein w/ excess glutamine residues

A

huntington’s!

CAG repeats are translated –> polyglutamine

40
Q

4 trinucleotide repeat diseases

A
  1. huntington
  2. myotonic dystrophy
  3. fragile X syndrome
  4. friedrich’s ataxia
41
Q

confabulation

A

unintentionally fabricates memories that he believes to be true

42
Q

wernicke-korsakoff vs. alzheimers & pseudodementia etc..

A

wernicke-korsakoff may also have ataxia (cerebellar degeneration)

alzheimers, pseudodementia, etc = NORMAL GAIT. more cortical / cognitive issues

43
Q

normal pressure hydrocephalus vs. wernicke-korsakoff

A

both have gait problems

no confabulation in NPH

44
Q

succinyl-CoA and glycine are starting products for..

A

heme synthesis
in mitochondria
via ALA synthase (w/ B6)

45
Q

starting substrates for pyrimidine de novo synthesis

A

glutamine + CO2

also need aspartate + PRPP

46
Q

from where are the nitrogen atoms in urea derivived from

A

ammonia & aspartate

47
Q

patient complaining of fatigue, myalgia, muscle cramps, weakness over a week w/ lots of urination.

due to furosemide or statin?

A

furosemide!
worry about electrolyte abnormalities!
-hypokalemia

statins can cause rhabdomyolysis, but will be ACUTE: generalized weakness, muscle pain, dark urine

48
Q

fatigue, myalgia, muscle cramp, weakness over a week

A

hypokalemia!

49
Q

psoas muscle originates from? how does it enter femur

A

T12-L4
combines w/ illiacus
forms common tendon to attach to lesser trochanter of femur (medial aspect)

travels below inguinal ligament.

pus can form near groin.

50
Q

3 effects of angII

A
  1. direct Na+ retention
  2. aldosterone production
  3. vasoconstrition
51
Q

HLA codes for

A
MHC class I and II
antigen presentation
class I: HLA A, B, C
class IIL HLA DP, DQ, DR
52
Q

CD40-CD40L

A

CD40 on B cell
CD40L on T cell

needed for B cell activation: class switching

53
Q

CD28-B27

A

CD28 on T cell
B27 on B cell

costimulatory molecule
w/ TCR & MHC interaction

w/o this: T cell -> anergy

54
Q

in what type of arthritis is carpometacarpal joint irritated

A

osteoarthritis (w/ DIP and PIP)

repeated mechanical trauma

see: joint space narrowing, subchondral sclersosis, eburnation, cyst formation, osteophytes

can feel crepitus on exam

55
Q

chondrosarcoma on X-ray

A

bony destruction at tumor site

56
Q

mechanical ventillation implies fixed (2)

A
  • total minute ventilation (TV x RR)

- FiO2

57
Q

generally, atelactasis results in..

A

right-to-left shunt -> hypoexemia

but will have hyperinflation of remaining non-collapsed alveoli, so physiologic dead spaced only increased slightly

58
Q

with fixed ventillation, how can hypercapnea develop

A

increase in pathologic deadspace (i.e. diffusion barrier)

59
Q

microsatellite instability

A

abnormal lengthening or shortening of macrosatellite repeats

related to HNPCC

60
Q

MEN I gene?

MEN II and II gene?

A

MEN I: inactivating mutation in menin tumor supressor

MEN II and II: activating mutation in RET proto-oncogene

61
Q

common presentation of endometriosis (3)? long term consequence?

A

dysmenorrhea
pelvic pain
dyspareunia

can have infertility: pelvic adhesions, fibrosis. distort pelvic anatomy and impair transport to oviduct.

if in bowel/bladder wall, can have painful defecation/urination too.

62
Q

CMV colitis

A

2nd most common CMV manifestation after CMV retinitis in HIV patients.

fever, anorexia, weight loss, abdominal pain.

mucosal erythema, erosion, ulcer

giant cells w/ large ovoid nucleus w/ centralized intranuclear inclusions “Cowdry”. like one big owel eye.

63
Q

gag codes for..

A

p24 capsid

64
Q

env codes for ..

A
gp120 (attachment)
gp 41 (fusion)

from cleavage of gp160

65
Q

pol codes for..

A

reverse trancriptase, aspartate protease, integrase

66
Q

mobile flank mass that produces a bruit

A

think: renal cell carcinoma!

which can obstruct IVC and cause ascities / peripheral edema

67
Q

consider IVC obstruction in..

A

any patient w/ sudden lower extremity edema