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Flashcards in Week 1 UWORLD Qs Deck (83):

How do phosphatidylcholine levels impact cholesterol gallstone formation?
Name rate limiting enzyme for cholesterol break down/bile salt formation in the liver

Makes cholesterol MORE soluble
Cholesterol - 7 alpha hydroxylase -> cholic and chenodeoxycholic acids = bile acids
*Enzyme targeted by FIBRATES, increases risk of gallstones b/c decreasing bile acids made which changes bile acid:cholesterol ratio
Bile acids + taurine/glycine = more soluble


What is the pathogenic CD 4 cell in Crohn's vs UC

Crohns: Th1
- Secrete IL2 + IFNg = granuloma
- Also activate macrophages which make TNF
UC: Th2 -> make cytokines/Ig that damage colon


Explain why Crohn's pts are at higher risk for gall stones - which kind?

Cholesterol gall stones
Disease affects terminal ileum - can't reabsorb bile acids
Bile now have less bile acid with more cholesterol - ratio changes to favor cholesterol -> cholesterol stones


Explain how these effect your risk for gall stones:
Spinal cord injury/total parenteral nutrition
Chronic hemolytic anemia

Statins decrease risk stones b/c limit cholesterol formation
Bladder hypomotility
Increase conj BR -> pigment gall stones


Name bugs that you see these things in STOOL:
1. Parasite eggs
2. Rhabditiform larvae
3. Proglottids
4. Trophozoites and cysts

1. Schistosoma
2. Strongyloides - eggs in GI wall
3. Intestinal tapeworms: taneia sol + sag, diphyll
4. Intestinal protozoans: giardia, e.histo


What substance has fastest rate of metabolism in glycolytic pathway: fructose, galactose, glucose, or mannose?

Bypasses fructokinase = one of rate lim enzymes of glycolysis
1. Glucose (hexo/glucokinase) -> G6P
G1P can enter at this step
2. G6P (phosphoglucoisomerase) -> fructose 6P
Mannose 6P can enter here
3. Fructose 6P (*PFK*) -> F16bisP
4. Separates into 2 G3P ----> pyruvate


What does carcinoembryonic antigen tell you about adenocarcinoma found @ sigmoid colon?

CEA for CRC recurrence


Describe why GI bacterial or helminthic infections increase risk pigment gall stones

Think E.Coli, Lumbricoides, or Clonorchis
Injured hepatocytes release *beta glucuronidase* = increases unconj BR
Pigment stones = Ca salts of unconj BR = "Cae bilirubinate"
Brown or black


Describe presentation and patho of lead poisoning

Microcytic anemia + constipation + AMS + h/o construction work
- Blue pigment at gum/tooth line
- Wrist or foot drop due to peripheral neuropathy
Lead X heme synthesis
Normal iron
BASOPHILIC STIPPLING b/c can't degrade RNA -> ribosome aggregation


Describe when you see
Heinz bodies
Ring sideroblasts
Howell Jolly bodies

Heinz - denatured Hgb, G6PD def after oxidative stress
Ring = RBC with big purple circle in it with blue dots around the outside = defective heme synthesis including lead poisoning but @ BONE MARROW not peripheral blood
HJ bodies - DNA remnant that should be removed by spleen, if seen signals splenic dysfxn


What is systemic mastocytosis and how does it affect the GI?

Clonal mast cell prolif - tyrosine kinase KIT receptor mutation
If all these mast cell degran -> excessive histamine release
Histamine can bind H2 receptors @ stomach -> increase gastric acid
Presents: rash, rubbing, scratching, itching after hot showers, light headed after standing, syncope in hot sun


What are you thinking if pt presents with masses in liver + ileum w/ flushing, redness, episodes of wheezing

Carcinoid syndrome - flushing, watery diarrhea, bronchospasm
Dx w 5-HIAA in 24 hr urine
Medical = octreotide = SS analog = Gi to decrease cAMP = less acid


Describe the colonoscopy + biopsy finding for:

Adeno - protruding mass, glands + dysplastic mucosa cells... duh adenocarcinoma
CMV - ulcers, CMV cells w/ inclusion bodies
Crypto - inflam w/o ulcers, basophilic dots on surface of mucosal cells (google image)
E.Histo - flask shaped ulcers, trophozoites that have eaten RBCs
Kaposi - red flat maculopap lesions or hmm nodules - *spindle shaped tumor w/ SV PROLIF*


What are the 3 types of adenomas you might see in the LI?

All form masses and can cause occult or visible bleeding -> Fe def anemia
1. Villous - "cauliflower like mass", most likely to become malig, secrete watery mucus -> secretory diarrhea
2. Tubular - colon cells form tube shaped glands
3. Tubulovillous = mix


What is the manometry for achalasia vs diffuse esophageal spasm

Achalasia - still get peristalsis but amplitude of all the waves is smaller, incomplete LES relaxation b/c no inhibitory ganglion cells
DES - all at once waves = simultaneous contraction of the esophagus (severe, retrosternal chest pain)


Name the order of 5 enzymes involved in DNA base excision repair

1. Glycosylase - recognizes abnormal base
2. Endonuc - cuts 5' end
3. Lyase - cuts 3' end
4. DNA pol fills in the 1 nucleotide
5. Ligase seals
Think about this pathway for repair of damage due to nitrates - promotes base deamination


Steps of appendicitis infection formation

Fecal mat'l obstructs
Build up mucous products in appendix
Wall distends -> decrease venous outflow -> ischemia -> bacterial infection
If wall necrosis, may rupture causing peritonitis


3 histo features of Celiac - name the screening panel for this disease

Vilous atrophy
Crypt hyperplasia


Why do anal fissures (aka tears) happen at the post midline of the anal canal and run up to the dentate line?

Due to chronic constipation + high P when passing hard stools
Low BF at post anal canal


Why do Chron's pts get kidney stones - what kind?

1. Less bile acids -> less fat absorption -> Ca binds fat and goes out in feces
2. Now nothing to compete for oxalate absorption (normally Ca ox can't be reabsorbed)
Think leaking GI epithelium - nothing holding back oxalate reabsorb
Ca oxalate stones


What diseases increase your risk of class adenocarcinoma vs cholangiocarcinoma?

Adeno = chronic chole -> porcelain GB
Cholangio = fibrotic diseases
- 1ary sclerosing cholangitis
- Liver fluke chronic infection


Olive mass in a baby stomach you thinking....

Pyloric stenosis due to SM hypertrophy
Non bilious vomiting


What is the histo of 1ary biliary cirrhosis

Liver biopsy = lymphocytes + GRANULOMATOUS destruction of interlobular bile ducts
= AI liver disease
Middle aged women
Fatigue + pruritis
Can't excrete bile from liver -> hyperchoelsterolemia w/ xanthelasma formation


Histo and presentation of 1ary sclerosing cholangitis

H/o UC + fatigue + high ALK PHOS
Inflam intra and extra hepatic bile ducts
Onion skinning round ducts


Histo of acute viral hepatitis

Ballooning degen!!
Mononuc inflam // apoptosis


What's the differential for proximal vs distal duodenal ulcers (anything past duodenal bulb)? What is the difference between endogenous and exogenous secretin

Prox: Hpylori, NSAID use
Distal: ZE
Endogenous secretin decrease gastrin, increase bicarb from pancreas
Exogenous STIM gastrin from gastrinomas (use to def ZE from other causes hypergastrin)


2 big drugs to treat hyper NH4

Lactalose = convert ammonia to ammonium
Rifaximin = antibiotic vs DNA dep RNA pol, decrease ammonia production by GI flora


What is biliary sludge?

Shit that accum when gallbladder isn't contracting
Think stone precursor


What's the histo of a Mallory Weiss tear

Repeated vomiting -> chest apin
Mucosal teal w/o acute inflam


What is Gilbert syndrome

Less UDP enzyme to cong BR in hepatocyte
No liver disese
Slightly high unconj BR aka high total bilirubin but normal direct aka conj BR
VS DUBIN JOHNSON - excess conj BR, totally normal liver tests with direct BR fraction of at least 50%


What are you thinking if
Fulm hepatitis w/ hepatocellular pattern of liver injury
High serum aminotransferase levels
PRolonged prothrombin time b/c liver isn't fxninh

Inhaled anesthetic heptatotox


Where does H Pylori colonize the stomach?

ANTRUM aka prepyloric area
Fundus = top, body, antrum = bottom


What causes Zenker diverticulum?

Cricopharyngeal motor dysfxn
Legit out pouching in prox esophagus - false divertic
Bad breath, choking feeling
Worried about aspiration


What drug interaction should you remember with XO?

6MCP - degraded by XO
Aka excess bone marrow suppression - super low white ct


If a patient presents with rusty colored urine, increased RBC and a kidney mass - what genetic syndrome should you take the leap to think about

1st - recognize RCC
2nd - tie VHL
Cerebellar hemagioblastoma
Clear cell renal cancer
3rd - know VHL: mutation chr 3 tumor suppressor gene
Even if you just have RCC alone, the likely mutation is the VHL mutation (even w/o VHL!!!)


What is alkaptonuria?

X homogenistic acid dioxygen = can't breakdown tyrosine -> fumigate for TCA cycle
1. Urine turns black when exposed to air
2. Black/blue face/skin
3. Ochronotic arthropathy = pigmented cartilage


Describe how stimulants work for ADHD

Release more NE + D @ *prefrontal cortex*
Yes it is weird that a drop in NT causes hyperactivity but think: this is because these NT should also mediate concentration


Explain mechanism by which brown fat generates body heat

Uncouple ETC + ATP production
H+ pumped out by ETC - back into matrix via protein *thermogenin*
Instead E is dissipated as heat


Name a drug and a food that can induce oxidative stress in G6PD def

Fava bens
TMP SMX (dapsone)
Also think DKA, infection


# needed to harm equation

= 1/AR
= 1 / (a/a+b) - (c/c+d)


Which drugs are you worried about with coronary steal?

Selective coronary artery vasodilators - don't use post MI
1. Adenosine
2. Dipryridamole


Explain amanita phalloides mushroom poisoning
1. Mechanism
2. Symptoms
3. Dx test

Liver gets concentrated with amatoxin
Binds DNA dep RNA pol type 2 -> X mRNA syn -> hepatocyte apoptosis
Watery, copious diarrhea
Test urine for alpha manitin


What is the difference between aspiration pna and pneumonitis? Discuss cause + presentation

Pna: oral cavity bugs (fuso, pepto, bacteroides) - DAYS after asp event
Pneumonitis: stomach bugs (HPylori) - HRS after asp event, treat supportively


Name the types of neurons found in
1. Striatum
2. Locus ceruleus
3. Nucleus baseless of Meynert
4. Red nucleus
5. Substantia nigra
6. Raphi nucleus

1. Caudate nucleus + putamen = striatum = motor activities; HUNTINGTONS lose Ach + GABA neurons @ striatium
2. Locus ceruleus = NE for fight/flight
3. Nucleus basalis of Meynert - Ach neurons; Alzheimer's decrease Ach here
4. Red nucleus @ ant midbrain, motor coordination of UE
5. Substania nigra = dopamine neurons, Parkinsons
6. Raphi nucleus - serotonin neurons


What should you be thinking with a patient who is vomiting, tachypnic + high NH4 blood and orotic acid in urine?

Ornithine transcarbamylase def


You know Huntington's is a trinucleodtide repeat disease in the huntingtin gene - but:
1. What is the repeat + chromosome
2. What is the effect of this mutation on neurons

CAG @ chr 4
Histone de-acetylation = DNA tighter = can't code for neuro protective genes -> neuron death


What is the role of mull inhibiting factor vs T vs DHT in male development?

MIF = from stroll cells so that internal female genital regresses
T = from Leydig cells, make internal sex organs
DHT - external make sex organs


Describe Epstein's anomaly and the teratogenic med that can cause it

1. "Atrialization of RV"
Move the tricuspid valve down
Decreases size RV


Describe the structure and the type of injury that would aggravate it
1. Ansernine bursa
2. Gastroc/semi membranous bursa
3. Supra patellar bursa
4. Pre patellar bursa

1. Anserine bursitis - (pes anserine) distal medial knee pain, obesity or athlete overuse
2. Popliteal cyst = Baker cyst = gastrocnemius or semi-membranous bursae, OA or inflam disease that pushes synovial fluid out ofhte joint into this bursa
3. Supra-patellar bursa = distal femur/quads, repeated quads activity (running) or direct trauma
4. Repeated keeling


Which CNS cell will undergo hyperplasia before making a scar after irreversible neuron damage?

Glia = astrocytes
Neuroectoderm origins, contain GFAP
1. Repair
2. Structural support
3. BBB
4. Metabolic


Describe where these are and what kind of injury could occur to each:
1. Deltoid ligament
2. Tib fib lig
3. Ant talo-fib ligament

1. Deltoid ligament - forced foot EVERSION but even then uncommon b/c so strong, harsh eversion more likely to see medial malleolus frx
2. Tib-fib ligament can be sprained but would present w/o major swelling, instead general instability + tenderness at that pt
3. Anterior talo-fibular ligament = sprained ankle


What part of the muscle cellular architecture allows for uniform, all at once muscle contraction? Aka if you didn't have these you would get uncoordinated myofibril contractions

T Tubules = extension of normal phospholipid bilayer w voltage gated DHP Ca channels
Triad = T-tub + A band + I band
Fxn = transmit deploy from membrane to the SR


If you were doing a thyroidectomy and your patient had the complication of a low, harsh voice - what happened during the surgery?

You cut the ext laryngeal nerve to circothyroid -> now tense vocal cords
INT laryngeal nerve = afferent cough reflex = damaged if you get food stuck in piriform recess
Vs all other arytenoid muscles innervated by L recurrent laryngeal nerve


Pseudo gout doesn't have uric acid crystals - that's gout. Describe pseudo gout crystals

INTRACELL Ca pyrophosphate crystals
Blue in parallel light, yellow in perpendicular


What type of enzyme is telomerase?

+ TTAGGG to 3' end
Once you burn through this know time for that cell to die


Cheyne Stokes breathing is seen in CHF - describe what it is

Period of no breathing causes drop O2 sats - must hypervent to make up for it
Then cycle restarts
No chest movement at the same time as no airflow means the 2 are still paired


Name stain for crypto meningitis vs pna

Pna: mucicarmine
Meningitis: India ink


What disease would cause 1 bout of vertigo vs recurrent?

Recurrent w/ change head position = benign paroxysmal positional vertigo b/c otoliths in the semicircular canals
Recurrent w/ ear ringing = *Meniere disease* = increase vol endolymph in inner ear
1 = vestibular neuritis


What is the antidote for serotonin syndrome?

Cyrophetadine = S R antag
SS - excess S (take MAO I + SSRI)
Clonus, hyperR, HTN, confusion


Cause of inherited vs acquired angioedema

Cong = C1 esterase def
Aqu = ACE I
Don't use ACE I for adult pts w/ C1 ext def


Presentation of aldose B def

Baby/kid vomiting + HYPOG after adding in normal foods
Fructose intol


Stat + formulate for "probably pt truly does not have positive test"

NPV = d/c+d


Where is the obstruction located for meconium ileus (CF) vs Hirschsprung

Meconium -> ileum
Hirsch -> recto sigmoid colon, + squirt signs aka rectal exam provokes forceful poop


Name the fxn of each nerve
1. Lingual
2. Maxillary
3. Phrenic
4. Recurrent laryngeal
5. Hypoglossal

1. Lingual nerve - off trigeminal, sensory to tongue
2. Maxillary nerve - off trigeminal, sensation to mid-face
3. Phrenic nerve - diaphragm, refers pain to shoulder (C5) or trap ridge (C3,4)
4. Recurrent laryngeal nerve - vocal cords
5. Hypoglossal innervates tongue


Explain mechanism of each for asthma treatment:
1. Cromylin, nedocromil
2. Omalizumab
3. Zleuton

C + N: Xgranule release -> stabilize mast cells, asthma prophylaxis (seasonal triggers, exercise)
Omal - binds IgE so can't cross link to activate mast cell
Zleuton - X lipo-oxygenase block effects of AA released from activated mast cells


Nickel exposure increases your risk of:

Nasal + lung cancer


What are CGD pts at high risk of infection with? Vs MPO def pts?

CGD = X NADPH oxidase (O2 => O2-) cat+ bugs: *burkholderia cepacia* serratia, nocardia, pseudomonas
NBT test doesn't turn blue (abnormal)
MPO = candida infections
NBT turns blue (norm)


What is the ductus venosus?

Umbilical art = high O2
Merges with IVC


What viruses does ether target?

Inactivates enveloped viruses -> makes no longer infectious


What is the drug that reduced nicotine cravings and makes smoking less pleasurable? Mechanism

Varenicline = partial n ACh R agonist
Less stim of downstream dopamine reward pathways


Why is ESR an indication of inflammation?

APRs induced by neutrophils and macrophages
APR includes fibrinogen which causes RBCs to form Rouleaux formations -> faster sedimentation rates


Attributable risk % in the exposed

Excess risk in an exposed pop that can be explained by the exposure to a risk factor
ARPe = 100 (RR-1)/R


Describe acyl coA dehydrogenase def

Impaired FA oxidation => hypoketotic hypoG
FA undergo B ox -> FADH2 + NADH -> ATP prod + ACoA for the citric acid cycle + ketone bodies
Deficient enzyme = can't use FA as E source
"1. Same presentation with Carnitine def - means can't get FA into mito to undergo B ox, wouldn't have to chose bet these 2 answers
2. Acetyl CoA carbox = 1st step FA SYNTHESIS aka not active during fast when breaking down
3. Acid alpha glucosidase // G-6-phosphatase // glycogen phosphorylase => gluconeogenesis "


Med to use acutely for subarach hemm

Nimodipine = Ca CB to stop vasospasm


Describe difference between
Nonsense mutations

Frameshift = +/-
Missense = wrong AA in
Nonsense = single base *substitution* = new stop


SLE pts are at higher risk for what complications due to having anti-phospholipid Abs

Will also have false + rapid plasma reagin test
1. Thrombo-emb duh... you know SLE is a hyper coat state
2. RECURRENT PREG LOSS (no mechanism)


Describe hyperPT findings vs osteoperosis

1. SUB-PERIOSTEAL resportion (@fingers)
2. Salt + pepper skull
3. Cysts in long bones = osteitis fibrosa cystica
Osteroperosis = traveler thinning with fewer interconnections


Describe symptoms if you damage
1. Basal pons
2. Caudate nucleus
3. Frontal cortex
4. Int capsule

"Damage to:
1. Base pons - contralat weakness + ataxia
2. Caudate nucleus - behav changes, speech/lang change, movement changes
3. Frontal cortex - social dishinhibition
4. Int capsule - motor"


Describe a thalamic stroke

R side sensory only stroke = THALAMIC STROKE
"VPL = input from spinothalamic tract + dorsal columns
VPM = input from trigeminal, projects to cortex via thalmaocortical fibers
Damage here -> complete CONTRA sensore loss
Aka sensory info gets here but doesn't make it to the cortex to be understood/received"


Which heart defect do you feel bounding peripheral pulses and a palpable apical thrill?

PDA - continuous machine like murmur alone L infraclavicular/L upper sternal border
Makes sense - think of where the problem is! High up connection pulm art + aorta


Drug drug ints with St John's Wart

"Induces cP450
Mean warfarin doesn't work as well b/c metab too quickly -> inadequate coag"
"Inducers: carbamazepine, barbituates, phenytoin, rifampin, modafinil, cyclophos
Inhibitors: amiodarone, cimetidine, flueoro, azloes, GRAPEFRUIT JUICE, isoniazid, ritonavir"


If you block a ureter resulting in hydronephrosis, what happens to GFR and FF?

Pressure from excess urine transmitted back to glomerulus - P pushing back against filtration pressure = drop GFR => drops FF


What structures arise from the metanephric mesoderm vs ureteric bud

MM: Gives rise to DCTs, glomeruli, Bowman's, PCT, loop
Uretric bud => collecting system: collecting ducts, major + minor calyces, renal pelvis, ureters