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Week 1 UWORLD Qs Flashcards

1
Q

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

A

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

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2
Q

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

A

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

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3
Q

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

A

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

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4
Q

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

A

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

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5
Q

Name bugs that you see these things in STOOL:

  1. Parasite eggs
  2. Rhabditiform larvae
  3. Proglottids
  4. Trophozoites and cysts
A
  1. Schistosoma
  2. Strongyloides - eggs in GI wall
  3. Intestinal tapeworms: taneia sol + sag, diphyll
  4. Intestinal protozoans: giardia, e.histo
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6
Q

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

A 
FRUCTOSE-1-PHOSPHATE
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
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7
Q

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

A

CEA for CRC recurrence

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8
Q

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

A

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

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9
Q

Describe presentation and patho of lead poisoning

A

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

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10
Q

Describe when you see
Heinz bodies
Ring sideroblasts
Howell Jolly bodies

A

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

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11
Q

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

A

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

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12
Q

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

A

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

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13
Q 
Describe the colonoscopy + biopsy finding for:
Adenocarcinoma
CMV
Crypto
E.Histo
Kaposi
A

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

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14
Q

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

A

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
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15
Q

What is the manometry for achalasia vs diffuse esophageal spasm

A

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)

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16
Q

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

A
  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
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17
Q

Steps of appendicitis infection formation

A

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

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18
Q

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

A

Vilous atrophy
Crypt hyperplasia
Lymphocytes

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19
Q

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

A

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

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20
Q

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

A
  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
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21
Q

What diseases increase your risk of class adenocarcinoma vs cholangiocarcinoma?

A

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

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22
Q

Olive mass in a baby stomach you thinking….

A

Pyloric stenosis due to SM hypertrophy
Non bilious vomiting
PROJECTILE

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23
Q

What is the histo of 1ary biliary cirrhosis

A

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

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24
Q

Histo and presentation of 1ary sclerosing cholangitis

A

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

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25
Histo of acute viral hepatitis
Ballooning degen!! | Mononuc inflam // apoptosis
26
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)
27
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 ```
28
What is biliary sludge?
Shit that accum when gallbladder isn't contracting | Think stone precursor
29
What's the histo of a Mallory Weiss tear
Repeated vomiting -> chest apin | Mucosal teal w/o acute inflam
30
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%
31
What are you thinking if Fulm hepatitis w/ hepatocellular pattern of liver injury Liver is SHRUNKEN High serum aminotransferase levels PRolonged prothrombin time b/c liver isn't fxninh
Inhaled anesthetic heptatotox
32
Where does H Pylori colonize the stomach?
ANTRUM aka prepyloric area | Fundus = top, body, antrum = bottom
33
What causes Zenker diverticulum?
Cricopharyngeal motor dysfxn Legit out pouching in prox esophagus - false divertic Bad breath, choking feeling Worried about aspiration
34
What drug interaction should you remember with XO?
6MCP - degraded by XO Aka excess bone marrow suppression - super low white ct CANCER AND GOUT WATCH OUT
35
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 Pheo 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!!!)
36
What is alkaptonuria?
AR X homogenistic acid dioxygen = can't breakdown tyrosine -> fumigate for TCA cycle Symptoms: 1. Urine turns black when exposed to air 2. Black/blue face/skin 3. Ochronotic arthropathy = pigmented cartilage
37
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
38
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
39
Name a drug and a food that can induce oxidative stress in G6PD def
Fava bens TMP SMX (dapsone) Also think DKA, infection
40
needed to harm equation
= 1/AR | = 1 / (a/a+b) - (c/c+d)
41
Which drugs are you worried about with coronary steal?
Selective coronary artery vasodilators - don't use post MI 1. Adenosine 2. Dipryridamole
42
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
43
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
44
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
45
What should you be thinking with a patient who is vomiting, tachypnic + high NH4 blood and orotic acid in urine?
Ornithine transcarbamylase def
46
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
47
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
48
Describe Epstein's anomaly and the teratogenic med that can cause it
Lithium 1. "Atrialization of RV" Move the tricuspid valve down Decreases size RV
49
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
50
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 ```
51
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
52
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
53
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
54
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
55
What type of enzyme is telomerase?
RT + TTAGGG to 3' end Once you burn through this know time for that cell to die
56
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
57
Name stain for crypto meningitis vs pna
Pna: mucicarmine Meningitis: India ink
58
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
59
What is the antidote for serotonin syndrome?
Cyrophetadine = S R antag SS - excess S (take MAO I + SSRI) Clonus, hyperR, HTN, confusion
60
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
61
Presentation of aldose B def
Baby/kid vomiting + HYPOG after adding in normal foods | Fructose intol
62
Stat + formulate for "probably pt truly does not have positive test"
NPV = d/c+d
63
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
64
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
65
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
66
Nickel exposure increases your risk of:
Nasal + lung cancer
67
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)
68
What is the ductus venosus?
Umbilical art = high O2 | Merges with IVC
69
What viruses does ether target?
Inactivates enveloped viruses -> makes no longer infectious
70
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
71
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
72
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
73
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 "
74
Med to use acutely for subarach hemm
Nimodipine = Ca CB to stop vasospasm
75
Describe difference between Frameshift Missense Nonsense mutations
``` Frameshift = +/- Missense = wrong AA in Nonsense = single base *substitution* = new stop UAG UAA UGA ```
76
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)
77
Describe hyperPT findings vs osteoperosis
HyperPT 1. SUB-PERIOSTEAL resportion (@fingers) 2. Salt + pepper skull 3. Cysts in long bones = osteitis fibrosa cystica Osteroperosis = traveler thinning with fewer interconnections
78
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"
79
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"
80
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
81
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"
82
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
83
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

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