UWorld Day Three

Question 1

Demyelination of a nerve directly decreases ___. Directly increases ___.

Answer 1

Decreases the length constant (the distance the impulse can travel).
Increases the time constant.

Question 2

Fever, tinnitus, tachypnia, and an empty pill bottle - what was ingested and what ABG toxicity?

Answer 2

Aspirin toxicity (two steps).

1. Respiratory alkalosis - salicylates directly stimulate the medullary respiratory center, causing hyperventilation.
2. Anion gap metabolic acidosis - salicylates increase lipolysis, uncouple oxphos, and inhibit TCA –> accumulation of organic acids in blood (ketoacids, lactate, pyruvate).

Question 3

What would the ABG (pH, PaCO2, HCO3) be 4-5 hours after aspirin toxicity?

Answer 3

normal range pH
low PaCO2 (respiratory alkalosis and compensation for metabolic acidosis)
low HCO3 (metabolic acidosis)

Question 4

Name the etiology and MOA:

A person ate sushi and presents with dizziness, weakness, loss of reflexes, paresthesias of face and extremities, N/V/D.

Answer 4

Tetrodotoxin from puffer fish binds to VGSC in nerve and cardiac tissue and prevents Na influx and depolarization.

Question 5

TPR in parallel v. in series for R1, R2, R3, R4

Answer 5

In parallel: 1/TPR = 1/R1 + 1/R2 + 1/R3 + 1/R4 —> TPR = 1/(total added)
In series: TPR = R1 + R2 + R3 + R4

Question 6

Antiepileptics with MOA of:

1. inhibiting presynaptic VGCaC
2. disrupting vesicle fusion
3. blocking VGNaC

Answer 6

1. Gabapentin
2. Leviteracitam
3. Phenytoin and carbamazepine

Question 7

A middle age man with SOB, elevated liver enzymes, and no history of smoking or alcohol.

Answer 7

Alpha-1 Antitrypsin. Panacinar emphysema with cirrhosis due to build up of AAT in liver.

Question 8

Morphine MOA

Answer 8

opioid. Morphine binds to mu-receptors, activating K-efflux, which hyperpolarizes and blocks pain conductance.

Question 9

lanosprazole

Answer 9

PPI (same as omeprazole)

Question 10

sx: PSVT

Admin ___ drug with AE of flushing, burning in chest, hypotension, AV block, SOB

Answer 10

adenosine - suppresses Ca influx.

Question 11

Nitroglycerine (AHF and severe HTN) does what to levels of:
LVEDP
Venous capacitance
Systemic Vascular Resistance

Answer 11

decrease
increase
decrease

Question 12

MOA of sulfonylureas and meglitinides

Answer 12

DM - increase insulin release (so increase C-peptide)

Question 13

What two drugs decrease hepatic glucose production and increase sensitivity to insulin?

Answer 13

Metformin and rosiglizazone

Question 14

Why take nitrates NOT around the clock?

Answer 14

because tolerance formation

Question 15

Drugs involved in anti-histone ab presence

Answer 15

SHIPP-E: Sulfa-drugs, Hydralazine, INH, Procainamide, Phenytoin, Etanercept (TNF-alpha inhibitors)

Due to acetylation

Question 16

Hyperphosphatemia, hypocalcemia, hyperK, hyperuricemia. Give what two drugs to decrease uric acid buildup during chemo-induced cell breakdown

Answer 16

hydration, allopurinol and rasburicase

Question 17

HypoK –> mm weakness and arrhythmias, shake and bake, type 1 RTA. What drug toxicity. (Histo infxn)

Answer 17

Amphoterecin B

Question 18

1. Two causes of angioedema (1 drug, one genetic) due to bradykinin buildup.
2. Two causes of angioedema due to mast cell activation.
3. Sx Difference between mast cell activation and bradykinin.

Answer 18

ACE inhibitors, C1 inhibitor deficiency –> NO PRURITIS OR URTICARIA

Type 1 HSR, IgE mediated and direct mast cell activation –> PRURITIS AND URTICARIA

Question 19

SE of what:
adipose - Lipolysis, altered fat distribution
adrenal cortex - atrophy
bone - osteoporosis
immune - suppression, T cell apoptosis
liver - increased gluconeogenesis and glycogenesis (LARGEST INCREASE IN PROTEIN SYNTHESIS)
skeletal muscle - atrophy
skin - thinning, stria, impaired wound healing

Answer 19

glucocorticoids

Question 20

Difference between competitive and noncompetitive antagonists on graph.

Answer 20

• Competitive cause graph to shift right, meaning higher concentrations of agonist can have same biological effect.
• Noncompetitive antagonists cause the competitive agonist curve to lower in biological activity because regardless of agonist concentration, its effects are blocked.

Question 21

__ = amount of drug given (mg) / plasma concentration of drug (mg/L)

Answer 21

Volume of distribution (L)

Question 22

What type of volume of distribution (low or high):

1. high molecular weight, high plasma protein binding, high charge, hydrophilicity
2. small molecular weight, uncharged (lipophilic or hydrophobic)

Answer 22

1. Low Vd because drug trapped in plasma compartment

2. High Vd because can cross easily through cell membrane into intracellular compartment

Question 23

COX-2 selective inhibitor (only inflammation).

AE

Answer 23

celcoxib

AE is thrombosis bc TXA2 (causes platelet aggregation) is dependent on COX-1 and thus, not inhibited.

Question 24

Calcium plays what role in vasculature?

So give CCB after what?

Answer 24

Causes vasoconstriction

Give CCB after a SAH to prevent cerebral vasospasm.

Question 25

Always use ___, even if HDL is low. MOA Do not administer wtih what type of drugs?

Answer 25

Use a statin to lower LDL (not niacin to increase HDL) - because statins decrease risk of CV event. Stains inhibit HMG-CoA Reductase Do not administer with drugs that inhibit CYP34A

Question 26

What lipid lowering therapy decreases serum TGs most? Primarily used to prevent pancreatitis in people with high HDL. MOA?

Answer 26

fibrates | MOA - activates transcription factor PPAR to increase lipoprotein lipase activity

Question 27

When do you give ezetimibe?

Answer 27

When person cannot take statin due to myopathy or hepatotoxicity.

Question 28

What drug inhibits Na/K ATPase pump, which increases Na intracellularly, promoting Ca influx through Na(out)/Ca(in) and increasing myocardial contractility?

Answer 28

Digoxin

Question 29

dobutamine - what type of drug?

Answer 29

Beta 1 adrenergic agonist. So Gs, increasing cAMP and increasing cytosolic Ca, increasing myocardial contractility.

Question 30

Biologic agents: - mab = - cept = - nib =

Answer 30

``` monoclonal ab (i.e. rituximab) receptor molecule (i.e. etanercept) kinase inhibitor (ie. imatinib) ```

Question 31

Open angle glaucoma (Increased IOP) drugs (three classes): ____ diminishes aqueous humor secretion by ciliary epithelium ____ decreases aqueous humor secretion by ciliary epithelium ____ decrease IOP by increasing outflow of aqueous humor

Answer 31

NS-Beta blocker (timolol) CAI (acetazolomide) PGF2alpha (latanoprost, travoprost) or Cholinomimetics (pilocarpine, carbachol)

Question 32

What molecule binds GP1b? Deficiency in the above molecule results in what change in blood tests? Function of ristocetin

Answer 32

vWF binds GP1b. Abnormal ristocetin and decrease F8, so increased PTT. Ristocetin activates vWF to bind GP1b.

Question 33

How is Bernard-Soulier different from vWF deficiency?

Answer 33

Bernard is hereditary deficit in GP1b receptors. vWF is a deficiency. Ristocetin will be abnormal for both, but when normal plasma is added, vWF will have a normal ristocetin test while Bernard will not.

Question 34

What is GP2b-3a deficiency? What is ristocetin test - abn or normal?

Answer 34

Glanzmann thrombasthenia. Normal ristocetin

Question 35

thrombocytopenia, enlarged platelets, mucocutaneous bleeding

Answer 35

Bernard-Soulier

Question 36

What is mosaisism, Robertsonian (unbalanced) translocation, and _____ = ___?

Answer 36

meiotic nondisjunction = 3 causes of Down Syndrome | meiotic nondisjunction can also cause Kleinfelter

Question 37

Alk phos measures what cell in bone remodeling?

Answer 37

osteoblast - it is released as bone matrix is synthesized also released from liver, placenta, and intestine. **bone alk phos is denatured by heat**

Question 38

TRAP, urinary hydroxyproline, and urinary deoxypyridinoline measure acitivity of what cell in bone remodeling?

Answer 38

osteoclast

Question 39

give what substance to promote apoptosis/menstrual bleeding?

Answer 39

medroxyprogesterone

Question 40

What is a drug used for peripheral artery disease that arterial vasodilates and decreases platelet aggregation?

Answer 40

cilastazol - a PDE inhibitor

Question 41

What IL-__ has ANTI inflammatory properities?

Answer 41

IL-10 (reduces Th1, MHC2, macrophages, and DC)

Question 42

MC pathogens that infect sickle cell patients

Answer 42

HiB and Strep pneumo

Question 43

Why is there pretibila myxedema in gRaves disease (hyper thyroid)

Answer 43

bc autoimmune response to TSH receptors causes buildup of glycosaminoglycans

Question 44

foot slap - nerve. cannot evert food, cannot feel sensation on dorsum or lateral shin

Answer 44

common fibular

Question 45

Causes pneumonia, brain abcesses, and cutaneous involvement in esp immunocompromised. Gram positive, catalase positive, Acid fast

Answer 45

Nocardia

Question 46

mucosal neuromas with marfanoid habitus

Answer 46

MEN 2B (pheo, mucosal neuromas, marfanoid habitus, medullary thryoid.

Question 47

Pancreatic tumor (esp gastrinoma), Pituitary (prolactinoma and visual defects), and Primary hyperparathyroid (hypercalcemia)

Answer 47

MEN1

Question 48

Medullary thyroid carcinoma (calcitonin), pheochromocytoma, parathyroid hyperplasia

Answer 48

MEN2A

Question 49

three Bacteria that use transformation - the direct uptake of naked DNA

Answer 49

Strep pneumo, Haemophilus, N gono/meningitidis

Question 50

S3 is best heard in left lateral decibitus position at _____ time. Abn in adults - indicates ___

Answer 50

ventricular enlargement, best heard at the end of exhalation

Question 51

Cardiac tamponade, COPD, severe asthma, and constrictive pericarditis all have what in common?

Answer 51

pulsus paradoxus (systolic >10mmHg different upon inspiration v expiration

Question 52

Arterial supply to ureters:

Answer 52

proximally is renal artery distally is superior vesicle artery in between in variable and anastomotic

Question 53

testosterone secreting ovarian tumor

Answer 53

sertoli-leydig

Question 54

What does mitochondrial vacuolization signify?

Answer 54

irreversible cellular damage

Question 55

"bilateral hilar LAD"

Answer 55

sarcodiosis

Question 56

what drug inhibits platelet aggregation by irreversibly blocking ADP receptors, which dows not allow for GP2b3a expression, thus inhibiting fibrinogen binding.

Answer 56

clopidogrel