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USMLE facts 2

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ang93's version from 2017-04-28 23:16

NBME

Histology

Question Answer
fat necrosisacute pancreatitis
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Microbiology

Question Answer
tx n meningIV ceftriaxone 2 wks
toxin blocks release of glycine and GABA from spinal inhibitory interneurons that regulate LMNstetanospasmin
what type of enzyme is tetanospasminmetalloprotease
how does tetanspasmin get to central inhibitory neuronsretrograde travel thru presynap peripheral MNs
trismuslock jaw
trismus, sardonic smile, back muscle contractions (opisthotonos)tetanus
what triggers tetanus spasmsminor stimuli such as loud noises
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Cardio/Pulm

Question Answer
acute endocarditiss. aureus
subacute endocarditiss. viridans
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GI

Renal

Neuro

Question Answer
spinal muscular atrophymutations in SMN1 gene - assembly of snRNPs in LMNs - impaired spliceasome fxn an degen of ant horn cells
collection of snrnpssplicesome
gusplice donor site
agsplice acceptor site
abranching point
decrease GABA, Ach, substance P in striatumhuntingtons
what happens to caudate in hungtingtonsloss of neurons in striatum
molecular path of huntingtonsNMDA receptors bind glutamate and cause neuronal death
damage to the nucleus ambigous of medullamyoclonus
lesions to subthalamic nucleus flinign mvmts of contralat exts (lacunar infarct)
myeloschisisspina bifida where spinal cord is exposed
wk of neural tube closure 4
vitamin B9folate
gene implicated in fragile xFMR1
neuropsych complications of fragile xanxiety disorders, autism, ADHD
what risk do cavernous hemangiomas of the brain confer?intracerebral hemorrhage, seizures
where are cavernous hemangiomas most commonly found?parenchyma of brain, supratentoral
gradual onset of sx, cresent shaped mass on CTsubdural hematoma
type of injury in subdural hematoma acceleration-deceleration, bridging cortical veins
bridging cortical veinscarry blood from cortex to venous sinus
gradually worsening headache and slow decline of mental fxnsubdural hematoma
MOA botulin toxinprevents presynap release of Ach
diplopia, dysphagia, dystoniabotulin toxin
toxin inhibits influx of sodium into nerve cellstetrodotoxin
weakness, paresthesias, loss of of reflexes, severe hypotension, concious pttetrodotoxin
TCA OD sxanticholingeric tox, MUSCARINIC BLOCKADE - not nicotinic
sensory ataxia and decreased pain sensation in distal exts w INHcompete w B6 - inc urinary excretion of B6 - deficiency
myotome shoulder/scapula elevationC4
myotome shoulder abductionC5
myotome elbow flexn, wrist extnC5,6
mytome elbo extn and finger extnC7
myotome wrist flexn finger flexnC8
myotome finger abductionT1
MOA gingival hyperplasia phenytoinmacrophages exposed to inc amts PDGF - stim prolif of gingival cells and alveolar bone
systems affected with phenytoin toxvestibular and cerebellar, nystagmus and ataxia
intial resistance to passive extn followed by sudden release of resistanceUMN lesions - clasp knife spasity
pure motor wkns, contral lat FALinternal capsule stroke
integrates body states w emotions, ANS control, conscious experience of visceral sensationsinsular cortex
putamen lesioncontralat tremor, bradykinesia, and rigidity
GPe lesiondec movmt
GPi lesionexcessive mvmt
occiptal morning headachesnonmalignant arterial HTN
heaches w papilledema, vomiting, and cognitive decline, worse in recumbent positionbrain tumor
why does the therapeutic window narrows with levadopa use?nigrostriatal degen
DA pthwy that regulates cognition and behaviormesolimbic and mesocortical
DA pathwy regs coordination of voluntary mvmtsnigrostriatal
DA pthwy inhibts prolactin secretiontuberoinfundibular
what can block tuberoinfundibular pthwayantipsychotics
hyperactivity of mesolimbic pthwypositive sx schizophrenia
negative sx schizophrenialow activity of mesocortical pathway
extrapyridamal effectsdystonic, akathisa, tardive dyskinesia
akathisacompelling need to move
D1 receptor bgdirect pathway
D2 receptor bgindirect
L-E syndrome is assocd wpreexisting malignancy (small cell carcinoma)
antibodies agst prsynap Ca channelsLE syndrome
tensilon test LE syndromeno improvement
nerve stim LE syndromeincremental response
MG assocd wthymoma
antibodies agst Ach receptorsMG
tensilon test MGimprovement or resolution of wkns
nerve stim MGdecremental response
anterograde transportkinesin
RER neuronsNissl substance
almost all volatile anesthetics increase ...cerebral BF
smoker, upper limb weakness/pain, ipsilat ptosis and miosispancoast tumor (nonsmall cell carcinoma)
deviation of uvula away from the lesionCNX, levator veli palatini
M1 receptor blockbrain, memory and cognitive fxn --> confusion
M2 receptor blockheart, decrease HR & ATRIAL contractility --> inc HR & atrial contractility
M3 effect in eyes and blockadepupillary spinchter contraction (miosis), ciliary muscle contraction (accomodatoin) --> loss ---> mydriasis, cycloplegia, acute angle glaucoma in elderly
how does M3 activate vasodilationreceptors on endothelial surface --> NO synthesis --> +GC --> cGMP inc --> +MLCP --> dephos myosin (inhib interaction w actin)
Ach & alzheimersdec Ach in hippocampus and nucleus basalis of Meynert, deficiency in choline acetyltransferase
striatum depleted of NMDA receptorsHuntingtons
locus ceruleus and assoc dzpanic disorder, caudal potine gray matter - contains large amts of NE
stepwise decline assocd w focal neuro sign wo impaired consciousness in early stagesvascular dementia
nonpharm treatments for insomniasleep hygiene, stim control, relaxn, sleep restriction, CBT
causes of horner syndromelesions to lateral hypothalmus, hypothalmospinal tract, paravertebral symp chain/stellate ganglion (pancoast tuomor) or internal carotid artery
corneal reflex afferent limb CNV
inability to abduct ipsilateral eye and horizontal diplopiaCNVI
corneal reflex efferent limbCNVII
hyperacusisCNVII lesion - lack of innervn to stapedius
gag reflex afferentCNIX
gag reflex efferentCNX
dysphoniaCNX lesion - lack of innervn to larygneal muscles
impaired swallowing w inability to elevate soft palateCNX - lack of innrvn to pharyngeal muscle
initial tx status epilepticusIV benzo (lorazepam)
MOA benzoenhances GABA-A receptors - allosteric attachment increased influx of negatively charges chloride in response to GABA binding
blocking VG-Ca channels - attenuating excitatory NT releasegabapentin
after IV benzo what do you give for status epilepticus txphenytoin
MC finding in PCA territory infarctioncontralateral hemianopia w macular sparing, contrlat parethesia and numbness (thalmus), dyslexia, agnoisa, and prosopagnosia (cant recog faces)
why is macula spared in PCA infarccollaterals from MCA
bs ant 4/5 part of corpus callosumACA
ant choroidal a suppliespost IC, optic tract, lateral geniculate body, choroid plexus, uncus, hippocampus, amygdala
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Psych

Question Answer
acute stress related disorder timeline3d - 1mo
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MSK

Question Answer
sudden upward jerking of arm at the shoulderbrachial plexus lower trunk injury
brachial plexus lower trunk injurymedian and ulnar
nerve root for klumpke palsyC8-T1
upward force on arm during delivery of babylower trunk injury
loss of intrinsic hand muscles (lumricals, interossei, thenar hypothenar)lower trunk injury
total claw handlower trunk injury
lumbricals normally ...flex MCP extnd PIP and DIP
erbs palsywaiters hand upper trunk injry
nerve root for waiters tipC5-C6
lateral traction on neck during deliveryerbs
erbs muscle lossloss of deltoid, supraspinatus, infrspinatus, biceps brachii
arm hangs by side, medially rotated, extened and pronatederbs
compression of lower trunk and subclavian vesselsthoracic outlet syndrome
muscle deficit in thoracic outlet syndromeintrinsic hand muscles
fxn deficit in TOSatrophy intrinsic hand muscle, ischemia, pain, edema
T1 involvemt in total claw hand deformityhorners syndrome
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Derm

Biochemistry

Immunology

Question Answer
antibodies w bacteriocidal effectIgG and IgM - complement mediated
IgA and n. meningincreased risked for disseminated infxn if they produce too much serum IgA
IgA action prevents attachmt to mucousal sufaces
pure t cell dysfxnthymic hypoplasia - digeorge
maldevelopmt of 3rd and 4th pharyngeal pouchdigeorge
memorize

Stats

Question Answer
the freq of a given characteristic (vitD intake) and given outcome (MS) used to study population data rather than the individualecological study
what should ecological studies not be used formaking conclusions about individuals wi these populations
ecological fallacymaking conclusions about individuals wi a population for an ecological study
odds of exposure to certain characterisitcs is compared between affected individs and unaffected who serve as controlscase-control
individuals are followed over time to determine incidence of disease of interestcohort
evaluate the exposures and outcomes of interest in individuals rather than populations at a given point in timecross sectional
start w cohort studies in which participants are followed over time and those participants who dvelop an outcome of interest become cases for a case control studynested case control
focused discussion groups, interviews (structured and semi structured) to obtain narrative info that can be crucial for explaining quantitative resultsqualitiative studies
1-Bstatistical power
a studies ability to detect a difference when one existsstat power
probability of rejecting the null hypothesis when it is truly falsestat power
power depends onsample size and difference in outcome btw groups
probability of committing type 2 errorB
researchers fail to reject null when it is truly falsetype 2 error
researchers reject the null hypothesis when the null is really truetype 1 error
study finds statistical different btw 2 grps when one truly does not existtype 1 error
atype 1 error
maximum probabilty of making type 1 error that the researcher is willing to accepta
probability of observing a given result due to chance alone assuming null is true (if there really isnt any different btw grps)p value
what is power typically set to80%
what is type 1 error typically set to.05
what does an "a" of 0.05 meanresearchers are willing to accept a 5% chance of making a type 1 error
if p is <0.05 what does this mean for astat signif result
commonly used to determine if the means of 2 populations are equaltwo sample t test
rqmts for t test2 mean values, sample variances (standard deviations) , sample size
p < 0.5 and t testnull hypoth rejected and 2 means assumed to be statistically different
model the linear relationship btw dependent variable and independent variablelinear regression
measure of strength and direction of linear relationship btw 2 variablescorrelation coeff
most appropriate for use with categorical datachi square test
evaluates whether the expected frequency of an occurrence is consistent w the observed freq "good fit"chi square
epidemiologic method of analyzing pool of data from several studiesmeta analysis
meta analysis increasesstat power beyond that of individual studies
correctly identify those w dzsensitivity
correctly identify those wo dzspecific
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Pharm - General

Question Answer
should be avoided when treatin insomnia in elderlybenzos, antihistamines, and sedating antidepressants
safe and effective method for tx insomnia in elderlyramelton
MOA rameltonmelatonin agonist
adverse effects volatile anestheticsmyocardial and resp depression, hypoTN, dec renal fxn
which inhaled anesthetic does not result in resp depressionNO
what aspect of inhaled anesthetics predispose them to post op atelectasissupress mucocilliary clearance
inhaled anesthetics that have bronchodilatory activityhalothane and sevoflurane
affect potassium channels in neuronal membranes and lock them in hyperpolarizationinhaled anesthetics
carbamazepineinducer
babrinducer
phenytoininducer
st johns wortinducer
rifampininducer
griseofulvininducer
cyclophosphamideinducer
modafinilinducer
amiodaroneinhibitor
cimetidineinhibitor
azole antifungalsinihbitor
fluoroquininhibitor
clarithromycininhibitor
isoniazidinhibitor
grapefruit juiceinhibitor
ritonavirinhibitor
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Pharm - Elderly Adverse Effects

Question Answer
arrythmias, n/v, confusion and weaknessdigoxin
delerium, falls, fracturesbenzos
cognitive decline, delerium, hallucination, orthostat hypotension, falls, urinary retention, constipation1st gen antipsychotics and TCAs
constipation, sedations, confusion, fallsopiod analgesics
inc risk stroke and mortality in dementia ptantipsychotic
hypoglycemialong acting sulfonylureas
tendon inflamn & rupturefluoroquinolones
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Toxicology

Question Answer
insomnia, tremulousness, anxiety, AN hyperactivityalcohol w/d 8-12 hr
alcohol w/d seizures12-48 hr
disorientation, severe agitiation, feveralcohol w/d "delerium tremens" 48-96 hr
prevention of seizure progression and delerium in alcohol w/dlong action benzos ( diazepam or chlordiazepoxide) - self tapering smooth w/d
liver dz pt w alcohol w/d txbenzo wo active metabs - lorazepam, oxazepam, temazapam (LOT)
outpatient management of mild alcohol w/dcarbamazepine
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Heme/Onc