uWorld 28 Flashcards

1
Q

what happens if you administer naloxone to a patine already in withdrawal

A

more severe withdrawal symptoms and potentially cause SEIZURES

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2
Q

neural tube defects occur due to FAILED FUSION of the neural tube during the 4th week of fetal development; what can be seen in the AMNIONIC FLUID due to leakage of fetal CSF

A

ALPHA-FETOPROTEIN (AFP)- crosses the placenta so can be measured in mothers serum

ACETYLCHOLINESTERASE

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3
Q

duodenal atresia is an example of failure of what

A

apoptosis

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4
Q

Hirschsprung’s disease is an example of failure of what

A

failure of migration

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5
Q

what cofactor is required for ALA synthase and thus a deficiency can cause microcytic hypochromic anemia

A

PYRIDOXINE (B6)

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6
Q

what are the side effects of using dihydropyridine calcium channel blockers (amlodipine, nifedipine) as antihypertensive mediations

A

PERIPHERAL EDEMA- related to preferential dilation of pre capillary vessels (arteriolar dilation), which leads to increased capillary hydrostatic pressure
-ACEI can normalize the increased hydrostatic pressure via post capillary venodilation

dizziness or lightheadedness
flushing

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7
Q

what prevents the SUPERFICIAL and what prevents the HEMATOGENOUS spread of CANDIDA

A

superficial: T LYMPHOCYTES
hematogenous: NEUTROPHILS

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8
Q

disseminated candidiasis (candidaemia, endocarditis) is more likely in what patients

A

those with NEUTROPENIA (since neutrophils protect against hematogenous spread of Candidia)

otherwise immunocompromised (cancer with chemotherapy)

those with inherited IMPAIRMENTS of pHAGOCYTOSIS

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9
Q

a T cell deficiency like AIDS predisposes one to what kind of Candida infection

A

SUPERFICIAL (oral/esophageal candidiasis, cutaneous candidiasis, Candida vulvovaginitis)

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10
Q

what is EFFECT MODIFICATION

A

when the effect of an exposure on an outcome is modified by another variable (not a bias)

EX: smoking status modified the effect of the new estrogen receptor agonist (exposure) on DVT incidence (outcome).

Smokers had a higher risk (RR over 1 and p value less than 0.05) while nonsmokers did not (p-value greater than 0.05)

a natural phenomenon that should be DESCRIBED NOT CORRECTED

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11
Q

what does a RR greater than one and a P less than 0.05 mean

A
increased risk (RR over 1)
statistical significance (p less than 0.05)
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12
Q

effect modification is easily confused with what

how are they separated

A

easily confused with CONFOUNDING

STRATIFIED ANALYSIS (analyzing the cohort as different subgroups) can help distinguish b/w the two

with effect modification, the different strata will have different measures of association (one p-value less than 0.05 and one above 0.05)

with confounding, stratification usually reveals no significant difference between the strata (both when separated will have p-values less than 0.05)

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13
Q

what is a confounder

A

something that is associated with both exposure and outcome and affects the measure of association b/w the exposure and outcome, such that there initially appears to be a statistically significant association b/w the 2 on crude analysis, but once STRATIFIED by the confounding variable, the association disappears

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14
Q

what are the most common pathogens causing nosocomial bloodstream infections

A

coagulase-negative staph
staph aureus
enterococci
candida species

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15
Q

indwelling central catheters predispose patients to what

A

bacteremia
sepsis
should be monitored regularly for signs and symptoms of infection

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16
Q

what are the 3 most predisposing factors for hypoglycemia in a patient with type 1 diabetes

A

excessive insulin dose
inadequate food intake
physical activity/exercise

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17
Q

why does exercise cause hypoglycemia in T1DM

A

if pt is on EXOGENOUS INSULIN the insulin will continue to be released form the injection site during exercise despite falling glucose levels

normally as glucose goes down in exercise, this stops the release of insulin and counter-regulatory hormones (glucagon) will increase endogenous glucose production via gluconeogenesis and glyogenolysis

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18
Q

what up regulates GLUT-4 in skeletal muscle

A
INSULINE
MUSCLE CONTRACTION (NO, AMP-activated kinase, Ca-calmodulin-activated protein kinase)
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19
Q

what does “degenerate” mean when referring to genetic code

A

more than 1 codon can code for a particular amino acid

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20
Q

what is the wobble hypothesis s

A

certain tRNA can recognize MULTIPLE DIFFERENT CODONS coding for the SAME ANIMO ACID

first 2 nucleotides require traditional watson crick base pairing, the third “wobble” spot may undergo less stringent (nontraditional) base pairing

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21
Q

what is the adherence site for DEXTRAN from strep viridans

A

FIBRIN/PLATELET aggregates (which are deposited at sites of endothelial damage)

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22
Q

what factors are associated with better TREATMENT ADHERENCE in an adolescent

A

CLOSE PEERS WITH COMPLEMENTARY BEHAVIORAL PRACTICES
positive family functioning
physician empathy
immediate benefits of treatment

adolescents are also less able to weight the risks and benefits of their decision b/c prefrontal cortex (center of executive function) is not fully formed until 3rd decade of life

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23
Q

what is the difference between TRACTION and PULSION diverticula (a way of classification)

A

TRACTION: created by inflammation and subsequent scarring of the gut wall, which typically results in pulling and out pouching of ALL gut wall layers (TRUE DIVERTICULA)

PULSION: increased intraluminal pressure created during strained bowel moments (due to chronic constipation or something) causes the MUCOSA and SUBMUCOSA to herniate through areas of focal weakness in the muscularis (FALSE DIVERTICULA)

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24
Q

diverticulosis most commonly affects where

A

SIGMOID COLON and is usually seen in peeps over 60

most peeps asymptomatic but can present with HEATOCHEZIA due to disruption of the arterioles adjacent to the diverticula

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25
Q

what are the symptoms of diverticulosis

A

LEFT LOWER quadrant pain
low-grade fever
constipation or diarrhea

due to INFLAMMATION

26
Q

where and from what would one see a traction diverticula

A

mid esophagus

mediastinal lyphadenitiis caused by TB or final infection

27
Q

the graph of serum creatinine and GFR looks like what

A

not linear (serum creatinine begins to rise sharply at GFR below 60

when GFR is normal, relatively large decreased in GFR result in only small increases in serum creatine

when the GFR is significantly decreased, small decrement in GFR produce relatively large changes in serum creatine

every time GFR halves, serum creatinine doubles

28
Q

what substances undergo no tubular reabsorption or secretion (filtered amount = excreted amount)

A

INULIN

mannitol

29
Q

what substances undergo net tubular reabsorption (excreted amount

A

glucose
sodium
urea

30
Q

what substances undergo net tubular secretion (excreted amount&raquo_space; filtered amount)

A

PAH

creatinine

31
Q

transduction of mechanical sound waves into nerve impulses occurs where

A

ORGAN of CORTI

  1. sound reaches middle ear by vibrating the tympanic membrane
  2. the vibration is transferred to the oval window by the ossicles
  3. vibration of the oval window causes vibration of the basilar membrane, which in turn causes bending of the hair cell cilia against the tectorial membrane
  4. hair bending causes oscillating hyperpolarization and depolarization of the auditory nerve, thereby creating nerve impulses from sound
32
Q

NOISE INDUCED hearing loss results from what

A

trauma to the STEREOCILIATED HAIR CELLS of the ORGAN of CORTI

HIGH-FREQUENCY hearing is lost FIRST (regardless of frequency of sound causing it)

bilateral

33
Q

what is the cochlear cupula

A

apex of the cochlea and is distant form the oval window

the distal cochlea primly registered LOW-FREQUENCY sound

34
Q

where do meningiomas tend to arise

A

DURAL REFLECTIONs (fall cerebra, tentorium cerebelli)

slow-growing (benign) intracranial tumor typically of adult

may present with SEIZURE, headache, or focal neurologic deficits depending on size and location

35
Q

what is thoracic outlet syndrome (TOS)

A

COMPRESSION of the LOWER trunk of the BRACHIAL PLEXUS as it passes through the THORACIC OUTLET

presents with:
upper extremity numbness, tingling, and weakness
upper extremity swelling (compression of SUBCLAVIAN VEIN)
exertional arm pain (compression of SUBCLAVIAN ARTERY)

most commonly occurs in SCALENE TRIANGLE

36
Q

what is the scalene triangle

A

formed by the anterior and middle scalene muscles and the first rib

the brachial plexus TRUNKS and subclavian ARTERY pass b/w the anterior and middle scenes; the subclavian vein runs anteromedial to the triangle

37
Q

where do the anterior and middle scalene originate and insert

A

anterior: C3-C6 transverse processes and attaches to the scalene tubercle of the first rib
posterior: C2-C7 transverse processes and inserts into the posterior of the first rib

38
Q

what can cause thoracic outlet syndrome (TOS)

A

anomalous cervical rib (extra one)
scalene muscular anomalies
injury (repetitive overhead arm movements, trauma)

39
Q

all antidepressants carry a risk of inducing what into susceptible patients

A
MANIA
bipolar I (manic episodes) are at greater risk
40
Q

what is the most important factor in determining prognosis of bladder cancer

A

TUMOR STAGE and depends on the DEGREE of INVASION into the bladder wall and adjacent tissues

41
Q

malformed teeth (Hutchinsons incisors and mulberry molars) are typical late manifestations of what congenital bug

A

SYPHILIS

42
Q

what is seen histologically in an amnionic fluid embolism (AFE) and what are signs of it

A

FETAL SQUAMOUS CELLS and MUCIN in the MATERNAL PULMONARY ARTERIES

hypoxia
hypotensive shock
DIC

43
Q

what drugs would exacerbate myopathy caused by statins (hint: think about metabolism)

A

statins are metabolized by CYP450 so CYP450 inhibitors would decrease statin metabolism thus increasing the serum concentration and thus increased risk for myopathy

ketoconazole, erythromycin, HIV protease inhibitors, grapefruit juice, cyclosporine, INH

44
Q

the immune reaction of TB is mediated by what

A

Th1 cells

caveating granuloma made up of:
T lymphocytes
epithelioid activated macrophages
Longhand giant cells (with horseshoe shaped arrangement of nuclei)
proliferating fibroblasts (synthesize collagen)

45
Q

in a patient successfully being treated for eczema with corticosteroid cream, what is seen at the site of application of the cream

A

dermal atrophy/thinning
associated with the loss of dermal collagen, drying, cracking, and/or tightening of the skin, telangiectasis, and ecchymosis

46
Q

what are the histologic findings of eczema

A

intraepidermal vesicles
superficial epidermal hyperkeratosis producing scales
epidermal hyperplasia (acanthosis)
chronic inflammatory infiltrate within the dermis

47
Q

what does entcapone do

A

stops the peripheral breakdown of levodopa to 3-OMD by blocking COMT- increases levodopa bioavailability to the brian

Tolcapone works both peripherally and centrally

used in Parkinson’s pts who experience end-of-dose “wearing off” periods with levodopa/carbidopa therapy

48
Q

what parkinson drug likely enhances the endogenous effects of dopamine

A

AMANTADINE- increases dopamine synthesis/release and inhibiting the reuptake of dopamine

49
Q

acute joint pain, swelling, and erythema with restricted range of motion is consistent with what

A

SYNOVITIS

potential causes:
septic arthritis (gonococcal, nongonococcal)
crystal arthropathy (gout)
hemarthrosis
rheumatic disease
50
Q

acute synovitis is best evaluated how

A

DIAGNOSTIC ARTHROCENTESIS and SYNOVIAL FLUID analysis

fluid should be sent for: crystal analysis, cell count, Gram stain, and culture

51
Q

what happens to a strawberry-type capillary hemangioma (juvenile hemangioma)

A

they FIRST GROW then they typically spontaneously REGRESS at or before puberty (usually start to fate between 1-3 years, and regress by 7 in 95% of cases)

lesion consists of unencapsulated aggregates of closely packed, thin-walled capillaries

can occur in liver, spleen, and kidneys

52
Q

what would a uterine specimen show if a patient has an ectopic pregnancy

A

DECIDUALIZED ENDOMETRIUM- DIALTED, COILED endometrial glands and VASCUALRIZED EDEMATOUS STROMA

occur int he luteal phase of the menstrual cycle, under the influence of PROGESTERONE, as the endometrium prepares for implantation

embryonic trophoblastic tissue will be absent

53
Q

tubal ligation (permanent sterilization) is a risk factor for what

A

ECTOPIC PREGNANCY

54
Q

methotrexate can cause both lung and liver toxicity, what is recommended for baseline

A

baseline chest x-ray and liver function tests are recommended

55
Q

classic galactosemia is caused by what

A

galactose-1-phosphate metabolism

galactose-1-phosphate uridyl transferase (GALT) is deficiency (no production of UDP-galactose and glucose-1-phosphate)

56
Q

untreated galactosemia can cause what and why

A

irreversible eye and liver damage

build up of galacticol in cells

57
Q

hematogenous osteomyelitis usually affects what part of the bone

A

METAPHYSIS of long bones (of young boys usually)

58
Q

what is chronic suppurative osteomyelitis

A

a condition in which necrotic bone (sequestrum) serves a reseviro for infection and becomes covered by a poorly constructed shell of new bone called an INVOLUCRUM

one or more sinus tracts develop to drain the purulent material into the soft tissue or out to the skin

TX: antibiotics and debridement of necrotic bone

59
Q

who is melanoma characterized on gross inspection (ABCDE)

A
Asymmetric shape
irregular or jagged Border
variability of Color
Diameter (greater than 0.5-1cm)
Evolution in size and appearance over time
60
Q

histologically what does melanoma look like

A

melanoma cells congregate in poorly formed nests and are large with irregular nuclei, clumped chromatin, and prominent nucleoli

61
Q

what is the most important prognostic factor in malignant melanoma

A

BRESLOW Depth

62
Q

multinucleate giant melanocytes are a characteristic finding in what

A

lentigomeligna melanoma