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zz - step 3 - uworld > uWorld 29 > Flashcards

uWorld 29 Flashcards

1
Q

organ susceptibility to infarction after occlusion of a feeding artery is ranked from greatest to least how?

A

CNS, myocardium, kidney, spleen and LIVER (least likely)

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2
Q

why are infarcts in otherwise normal liver rare

A

DUAL BLOOD SUPPLY

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3
Q

what are microvilli made up of

A

actin

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4
Q

what is Nissle substance

A

RER in neurons

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5
Q

what is an examples of enhanced ability to penetrate bacteria due to synergism

A

penicillins stopping peptidoglycan cell wall synthesis allowing aminoglycosides to gain access to the cell interior, where they act on the 30S subunit of the bacterial ribosome

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6
Q

what are the two pathways of angioedema

A

mast cell activation (Type 1 hypersensitivity, direct mast cell activation- like opioids)
-associated pruritic and urticaria

excess bradykinin (ACEI, C1 inhibitor deficiency)
-NO pruritic and urticaria
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7
Q

what type of hypersensitivity is acute hypersensitivity pneumonitis (and what causes it)

A

specific serum IgG antibodies that precipitate bacterial or fungal antigens found in inhaled organic dust particles

causes interstitial alveolitis and bronchiolitis via IMMUNE COMPLEX and COMPLEMENT DEPOSITION in vessel walls (Type III Hypersensitivity)

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8
Q

what causes a bruise to change color from bluish to greenish

A

HEME OXYGENASE (contained in macrophages and some other cells) degrades heme to BILIVERIDEN, CO, and Fe3+

biliveriden is GREEN in color and is further reduced (by biliverdin reductase) to bilirubin (yellow pigment) which is transferred to liver bound to albumin

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9
Q

what is seen in acute and chronic vitamin A toxicity (overdose)

A

Acute: nausea, vomiting, vertigo, blurred vision

Chronic: alopecia, dry skin, hyperlipidemia, hepatotoxicity, hepatosplenomegaly, visual difficulties
PAPILLEDEMA when present is suggestive of CEREBRAL EDEMA in the setting of bending intracranial hypertension (PSEUDOTUMOR CEREBRI)

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10
Q

large doses of vitamin C are associated with what

A

false negative stool guaiac results
diarrhea
abdominal bloating
maybe calcium oxalate nephrolithiasis

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11
Q

large doses of vitamin E are associated with what

A

higher mortality rates due to hemorrhagic stroke in adults

higher rates of necrotizing enterocolitis in infants

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12
Q

What is BLOOM syndrome

A

AR disorder of mutation in BLM gene that encodes for DNA HELICASE (enzyme responsible for unwinding of the double helix)

chromosomal instability and breakage manifesting as:
GROWTH RETARDATION
FACIAL ANOMALIES (microcephaly)
PHOTOSENSITIVE RASH
IMMUNODEFICIENCY (recurrent infections)
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13
Q

what prevents reannealing of the ssDNA during replication

A

ssDNA-binding proteins- they bind to and stabilize the ssDNA, preventing it fro reannealing

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14
Q

what does topoisomerase do

A

relieves tension in supercoils by introducing transient single- or double-stranded nicks in the DNA (located ahead of helices on the dsDNA segment of the relocation fork)

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15
Q

what is the treatment of choice for specific phobia

A

behavioral therapy (systematic, repeated exposure to the phobic stimulus)

typically done in a step-wise manner, resulting in decreased anxiety over time as habituation and extinction occur

can be done in vivo (most effective), imaginal, or virtual reality

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16
Q

cutaneous neurofibromas are predominately comprised of what

A 
they are benign nerve sheath neoplasms made up mostly of
SCHWANN CELLS (NEURAL CREST derivatives)
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17
Q

the neural tube gives rise to what

A 
neurons of CNS
neurohypophysis
retina
pineal gland
preganglionic autonomic fivers
astrocytes
ependymal cells
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18
Q

the vertebrae are derived from what

A

paraxial mesoderm

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19
Q

the surface ectoderm gives rise to what

A 
epidermis
lens of eye
outer layer of cornea
nasal and oral epithelium
olfactory epithelium
inner ear sensory organs
anal epithelium below the dentate line
Rathkes pouch
salivary, sweat, and mammary glands
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20
Q

what are acute dystonia and akathisia

A

acute dystonia:

  • 3-4 days after starting
  • distressing, sustained, involuntary contraction of the neck, mouth, tongue, or eye muscles

akathisia- physical restlessness, difficulty sitting still, compelling need to move

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21
Q

how does the kidney try and make up for metabolic acidosis

A

increased HCO3- resorption
increased H+ secretion
increased acid buffer excretion ((HPO4)2- and NH3 which get excreted as H2PO4- and NH4+)

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22
Q

what are PROTHROMBIN COMPLEX CONCENTRATES

A

contain the vitamin K-dependent factors II, VII, IX, and X

can be used in bleeding due to WARFARIN OVERDOSE (along with fresh frozen plasma)

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23
Q

what do aminocaproic acid and tranexamic acid do

A

inhibit fibrinolysis by inhibiting plasminogen activation (tPA, alteplase, reteplace, streptokinase, tenecteplase)

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24
Q

what anticonvulsants should be avoided in someone with juvenile myoclonic seizures (and all generalized epilepsy syndromes for that matter) and why

A

narrow-spectrum anticonvulsants (phenytoin, carbamazepine, gabapentin, phenobarbital)

they can aggravate seizures

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25
Q

what is used to treat juvenile myoclonic epilepsy (JME)

A

broad-spectrum anticonvulsant

VALPROIC ACID, lamotrigine, levetiracetam, topiramate

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26
Q

what is fluphenazine

A

dopamine antagonist (typical antipsychotic)

used to treat Tourette syndrome

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27
Q

in a patient with known mitral stenosis what finding in the heart is suggestive of aortic valve involvement too

A

left ventricular DIASTOLIC PRESSURE INCREASE

b/c this would be normal or decreased in mitral stenosis alone

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28
Q

what pressure changes does mitral stenosis cause

A

elevated left atrial diastolic pressure, therefore causing:
elevated pulmonary capillary wedge pressure
pulmonary hypertension
decreased pulmonary vascular compliance
right ventricular dilation
functional tricuspid regurgitation

29
Q

where are the ethmoid air cell and when are they injruted

A

medial to the orbit

can be affected in BLOWOUT fractures of the orbits MEDIAL WALL

30
Q

what is an inferior orbital blowout fracture

A

orbital contents spill into MAXILLARY SINUS

thin bone bordering MAXILLARY SINUS at inferior orbit
blunt trauma to the eye causes rapid increase in pressure that does not typically rupture the globe but is transferred into the orbit where weak points (inferior and medial) can blow out

31
Q

acetylcholine release from presynaptic terminal vesicles at the NMJ depend on what

A

influx of extracellular calcium into the presynaptic terminal

calcium influx happens following depolarization and opening of voltage-gated calcium channels

32
Q

what are the in utero CMV complciations

A 
CHORIORETINITIS
sensorineural deafness
seizures
jaundice
hepatomegaly
splenomegaly
microcephaly
33
Q

what sleep problems are seen in narcolepsy

A

shortened sleep latency
enter rapid eye movement sleep almost immediately

recurrent lapses into sleeps or naps (at least 3 times per week for 3 months)

hypocretin-1 (orexin) levels are low

34
Q

what is hyper somnolence disorder

A

diagnosed when excessive and impairing daytime sleepiness cannot be explained by another sleep disorder

persistent daytime sleepiness rather than the “sleep attacks” seen in narcolepsy

these pts do not feel refreshed after naps

35
Q

what are the effects of nitroprusside

A

BALACNED VASOdilator and VENOdilator

thus it decreases both preload and after load, and it is balances so SV is maintained

36
Q

how does NOCARDIA present

A

sputum stain- weakly GRAM-POSITIVE, catalase-positive, rod-shaped bacteria that form partially acid-fast BRANCHING FILAMENTS

typically lung (cavitary pneumonia that looks like TB), brain, or skin manifestations in the immunocompromised

RING-ENHANCING focal lesion with surrounding edema
dyspnea, cough, fatigue, night sweats
fever, headache
transplant recipient on immunosuppressive therapy
lethargic w/ patchy lung crackles
increased leukocyte count
nodules but no parenchymal infiltrate on X-ray

37
Q

what causes closure of epiphyseal plate (growth plate)

A

sex hormones (estrogen, testosterone)

38
Q

what defines precocious puberty in Caucasian females

A

development of secondary sexual characteristics before after 7

excess steroids cause premature fusion of growth plate and full potential height is never reached

39
Q

what are estrogens affects on the bone at sites other than the epiphyseal growth plate

A

anabolic
stimulate osteoblastic deposition and decrease osteoclastic bone resorption

low estrogen states (menopause), are associated with rapid bone loss

40
Q

what is the role os somatomedin C (IGF-1) at the epiphyseal growth plate

A

proliferation of chrondocytes causing increase in linear growth

no effect on closure of the plate (which is why it can lead to gigantism)

41
Q

what is teriparatide

A

recombinant molecule identical to the 34-amino-acid sequence at the N-terminal portion of endogenous PARATHYROID HORMONE

stimulates MATURATION of PRE-OSTEOBLASTS into bone-forming OSTEOBLASTS that lay down collagen and eventually mineralize the matrix

42
Q

what does denosumad do

A

human monoclonal antibody to receptor activator of nuclear factor KappaB ligand (RANKL)

RANKL is part of the tumor necrosis factor family and is required for OSTEOCLAST function

43
Q

what causes a lacunar infarct

A

ischemic stroke of SMALL PENETRATING VESSELS that supply the deep brain structures (basal ganglia, pons) and subcortical structures (internal capsule, corona radiata)

CHRONIC HYPERTENSION which predisposes arterioles to undergo lipohyalinosis, microatheroma formation, and occlusion (HYPERTENSIVE ARTERIOLAR SCLEROSIS)

smoking and diabetes are other risk factors

44
Q

a lacunar infarct where causes PURE MOTOR hemiparesis

A

POSTERIOR limb of the INTERNAL CAPSULE or BASAL PONS

45
Q

a lacunar infarct where causes PURE SENSORY stroke

A

VENTROPOSTEROLATERAL or VENTROPOSTEROMEDIAL THALAMUS

46
Q

a lacunar infarct where causes ATAXIA-HEMIPLEGIA SYNDROME

A

POSTERIOR LIMB of INTERNAL CAPSULE or BASAL PONS

47
Q

a lacunar infarct where causes DYSARTHRIA-CLUMSY HAND SYNDROME

A

GENU of the INTERNAL CAPSULE or BASAL PONS

48
Q

brain arteriovenous malformations typically present how

A

intracranial hemorrhage in children

49
Q

what is a Charcot-Bouchard Aneurysm

A

ypcially caused by CHRONIC HYPERTENSION and results in hemorrhagic stroke involving deep brain structures (basal ganglia, cerebellar nuclei, thalamus, pons)

hemorrhage would appear as a focus of INTRAPARENCHYMAL HYPERDENSITY on the initial CT scan

50
Q

what is the most common cause of spontaneous lobar/cortical hemorrhage (occipital, partial) in the elderly

A

cerebral amyloid angiopathy

51
Q

what is seen in chronic RENAL ALLOGRAFT rejection

A

gradual deterioration in graft function that occurs at least 3 months post-transplant in the absence of other precipitating events (active acute rejection, withdrawal of immunosuppression)

characterized by WORSENING HYPERTENSION, a PROGRESSIVE RISE in serum CREATININE, and proteinuria with normal urine sediment

mediated by a chronic, indirect immune response against donor allo-antigens and results int OBLITERATIVE INTIMAL THICKENING

52
Q

vascular fibrinoid necrosis and neutrophil infiltration of the arterioles, glomeruli, and peritubular capillaries are characteristic of what type of transplant rejection

A

hyper acute rejection of a renal allograft

53
Q

a dense interstitial mononuclear infiltrate is characteristic of what kind of transplant rejection

A

ACUTE cellular rejection

typically happens within 6 months of procedure but can occur later if immunosuppressants are stopped

54
Q

what is hydralazine

A

direct vasodilator often used in combo with isosorbide dinitrate for treatment of heart failure

ADRs: tachycardia and orthostatic hypotension

55
Q

what are the effects of prolonged portal hypertension (say to do cirrhosis)

A

varices at the 4 sites of portocaval anastomoses (esophagus, rectum, umbilicus, and retroperitoneal)

ascites

56
Q

who is ascites (secondary to liver cirrhosis) treated

A

resting sodium intake and diuretics (furosemide and sptinolactone in combo is most common prescription)

57
Q

what is the most common eye involvement of diabetes

A

unilateral CN III involvement (DIABETIC CNIII MONONEUROPATHY)

58
Q

what is diabetic CN III MONONEUROPATHY

A

due to ISCHEMIC NERVE DAMAGE

acute onset DIPLOPIA
“DOWN and OUT” position of eye
PTOSIS (paralysis of levator palpebrae)

PUPILLARY SIZE and REACTIVITY is NORMAL (major key b/w this and compression of CNIII)

59
Q

diabetic mononeuropathies are cased by what

A

ischemic nerve damage

60
Q

what are the upper motor neuron signs

A

spastic paralysis
clasp-knife rigidity
hyperreflexia
babinski sign

61
Q

what are the lower motor neuron signs

A

flaccid paralysis
hypotonia
hyporeflexia
muscle atrophy and fasciculations

62
Q

what is MYOCARDIAL HIBERNATION

A

state of CHRONIC MYOCARDIAL ISCHEMIA in which both myocardial metabolism and function are reduced to mach a concomitant reaction in coronary blood flow (due to moderate/severe flow-limiting stenosis)

new equilibrium prevents necrosis

chronically hibernating myocardium demonstrates decreased expression and disorganization of contractile and cytoskeletal proteins, altered androgenic control, and reached calcium responsiveness

changes lead to DECREASED CONTRACTILITY and LV SYSTOLIC DYSFUNCTION

coronary REVASCULARIZATION and subsequent RESTORATION of BLOOD FLOW to hibernating myocardium IMPROVES CONTRACTILITY and LV FUNCTION

63
Q

what is ischemic preconditioning

A

phenomenon in which brief repetitive episodes of myocardial ischemia, followed by reperfusion, protect the myocardium from subsequent prolonged episodes of ischemia

ex: repetitive episodes of angina before MI can delay cell death after complete coronary occlusion and therefore provide greater time for myocardial salvage with coronary revascularization

64
Q

what is ventricular remodeling

A

change in the structure (cardiac mass and dimensions) or function of the heart in response to cardiac injury or hemodynamic changes (pressure/volume overload)

can occur in long-term myocardial hibernation, but takes weeks to months to recover following reperfusion therapy

65
Q

what is seen with an OBSTRUCTION of the RIGHT BRACHIOCEPHALIC (INNOMINATE) VEIN

A

could be due to external compression by an apical lung tumor or thrombotic occlusion as can occur with central catheter placement for extended period of time

formed by union of right subclavian vein and the right internal jugular vein

right external jugular drains into right subclavian and thus obstruction can cause venous congestion of structures drained by external jugular vein

DRAINS RIGHT LYMPHATIC DUCT: which drains lymph from right upper extremity, the right face and neck, the right hemithroax, and the right upper quadrant of the abdomen
-blockage of this = SWELLING

both brachiocephalic veins join to form SVC (compressed both sides of face swollen in SVC SYNDROME)

66
Q

intravascular hemolytic anemias are characterized by what lab findings

A

DECREASED serum HAPTOGLOBIN

INCREASED LDH and BILIRUBIN

67
Q

what is haptoglobin

A

serum protein that binds free hemoglobin and promotes its uptake by the reticuloendothelial system

levels decrease when significant quantities of hemoglobin are related in the circulation (like in INTRAVASCULAR HEMOLYSIS)

68
Q

decreased reticulocyte could in the presence of anemia is characteristic of what?

A

APLASTIC anemia

69
Q

what is thought to cause atopic dermatitis

A

mutations affecting proteins such as filaggrin or other components of the epidermis, resulting in IMPARIEMTN of the SKIN’S BARRIER FUNCTION
this increases the immunologic exposure to environmental allergens and microbial antigens, leading to immune hypersensitivity

affected patients have HIGH serum IgE levels, peripheral EOSINOPHILIA, and high levels of cAMP PHOSPHODIESTERASE in their leukocytes

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