USMLE Rx: Week of 11/21/16

Question 1

On what receptor does ADH act to cause water retention?

Answer 1

V2 (Think… “2 = tubule”)

Question 2

True or false: carcinoid syndrome results from a primary carcinoid tumor.

Answer 2

False. Carcinoid syndrome results from metastasis to the liver.

Question 3

Clay stools result from _____________.

Answer 3

obstruction of the gallbladder

Question 4

Delayed detachment of the umbilical cord is synonymous with ___________.

Answer 4

LAD (think, “the umbilical cord ADHEREs too long”)

Question 5

LAD results from a defect in CD______.

Answer 5

18

“You’re no longer a LAD when you turn 18.”

Question 6

Phosphorylation of mannose residues takes place in which organelle?

Answer 6

The cis-Golgi (the Golgi is the organelle that directs cellular traffic, so it makes sense that mannose phosphorylation would take place here because it directs proteins to lysosomes)

Question 7

Those with AIDS have the most trouble annihilating ___________.

Answer 7

intracellular pathogens (like Listeria or TB)

Question 8

Which layer of colonic tissue, when attenuated, causes diverticulosis?

Answer 8

Muscularis propria

Question 9

What drug should be empirically given to a young adult with suspected meningitis?

Answer 9

Ceftriaxone

Question 10

Aminoglycosides and tetracyclines both work on the 30S subunit. Which one inhibits tRNA binding?

Answer 10

Tetracycline (T for T!)

Question 11

Alcohol metabolism leads to a ___________ NADH:NAD+ ratio.

Answer 11

increased; this is important because NAD+ must be present for glycolysis to continue, so pyruvate gets converted to lactate and thus hypoglycemia can occur because of deficient pyruvate

Question 12

HNPCC increases what other non-GI cancer?

Answer 12

Endometrial, ovarian, and urinary tract

Question 13

Histologically, how can you differentiate hereditary hemochromatosis and hemosiderosis?

Answer 13

Hemosiderosis will present with iron in macrophages, while hemochromatosis will present with iron in hepatocytes.

Question 14

What kind of protein is involved in the disorder that presents with cafe-au-lait spots?

Answer 14

An inhibitor of ras (NF-1 on chromosome 17)

Question 15

What might blistering on and in the mouth suggest in a patient taking an anticonvulsant?

Answer 15

SJS (can present in those taking phenytoin, carbamazepine, ethosuximide, and lamotrigine)

Question 16

An elderly patient presents with a magnetic-foot gait, incontinence, and recent problems with memory. You check for papilledema and find none. What is likely happening?

Answer 16

Normal-pressure hydrocephalus, which only presents with elevated ICP intermittently (“wet, wobbly, and wacky”).

One important distinction from Alzheimer’s is that those with Alzheimer’s typically develop a lack of coordination late in their disease progression, so if someone is only mildly mentally impaired but has gait disturbance then suspect NPH.

Question 17

What drug should you give to someone with new-onset diarrhea, tricuspid regurgitation, and periodic flushing?

Answer 17

Octreotide (being carcinoid syndrome)

Question 18

What histologic appearance do carcinoid tumors have?

Answer 18

Rosettes

Question 19

What drugs should be given to someone with multiple myeloma metastasized to the bone?

Answer 19

Bisphosphonates (alendronate and risedronate)

Question 20

What side effect might you worry about in a person taking alendronate who got a tooth extracted?

Answer 20

Osteonecrosis of the jaw

Question 21

Mitochondrial disorders typically present with what tissues most affected?

Answer 21

Nerves and muscles, because both need lots of energy; think of mitochondrial disorders when someone presents with muscle weakness and nerve dysfunction (such as vision problems)

Question 22

If you’re given a diagram showing desmosomes and adherens junctions, how can you distinguish the two?

Answer 22

Desmosomes have cytoskeletal filaments that radiate outward, while adherens junctions have straight cytoskeletal filaments.

Question 23

What are the two steps of galactose metabolism? Which is more commonly affected in galactosemia?

Answer 23

Galactose -> galactose 1-phosphate
Galactose 1-phosphate -> to UDP-galactose -> glucose 1-phosphate

The second step is most commonly impaired in babies with galactosemia.

Question 24

How can you remember which type of GPCR goes with which receptor?

Answer 24

“After QISSeS, you get a QIQ out of SIQ SQS.”

It goes alphabetically:

• Adrenergic:
• a1 = Gq
• a2 = Gi
• b1 = Gs
• b2 = Gs
• b3 = Gs
• Muscarinic:
• m1 = Gq
• m2 = Gi
• m3 = Gq
• Dopamine:
• d1 = Gs
• d2 = Gi
• Histamine:
• h1 = Gq
• h2 = Gs
• Vasopressin:
• v1 = Gq
• v2 = Gs

Question 25

What kind of dementia is likely in a patient with visual hallucinations?

Answer 25

Dementia with Lewy bodies

Question 26

Those with Crohn's are often given an antibody that attacks soluble __________.

Answer 26

TNFa (being infliximab; think "in-floats-imab")

Question 27

What antibiotic inhibits translocation through the ribosome?

Answer 27

Macrolides ("It's like a MAC truck parked on the tracks... the train can't go.")

Question 28

Informed consent is not needed in emergencies. What is the exception to this rule?

Answer 28

If the patient has previously told you that they don't want care in that emergency, then the correct course of action is to comply with the patient's wishes and not administer care.

Question 29

The esophageal veins arise from the ____________.

Answer 29

left gastric vein

Question 30

There are five drugs that act on microtubules: vinca alkaloids, colchicine, paclitaxel, ________, and __________.

Answer 30

griseofulvin (antifungal); mebendazole (antihelminthic)

Question 31

Aldosterone increases the excretion of two things: _____________.

Answer 31

protons and potassium

Question 32

Left shoulder pain and LUQ abdominal pain are indicative of _______________.

Answer 32

thrombosis to the splenic artery

Question 33

What cell type do Warthin's tumors arise from?

Answer 33

Lymphoid cells

Question 34

Occlusion of the ____________ artery can lead to "locked-in" syndrome, a state in which people are fully conscious but only able to blink.

Answer 34

basilar

Question 35

What are some characteristics of pathologic grief?

Answer 35

Delayed grief: not feeling anything at the time but then grieving months or years later Inhibited grief: denying feeling anything Excessive or prolonged grief

Question 36

What amino acids are essential?

Answer 36

All of the ketogenic and ketogenic/glucogenic; valine, methionine, and histidine

Question 37

____________ are conditionally essential amino acids.

Answer 37

Arginine and cysteine

Question 38

What are the four Ds of physician malpractice?

Answer 38

Dereliction of Duty causing Direct Damage to the patient

Question 39

Describe the presentation of myotonic dystrophy.

Answer 39

It is a nucleotide repeat disorder that presents with proximal muscle weakness, delayed relaxation of muscles, cataracts, and glucose intolerance. CCTG repeat: cataracts, chair-bound, tense, glucose

Question 40

Differentiate the mechanisms of vancomycin and the beta-lactams.

Answer 40

Vancomycin inhibits peptidoglycan polymerization (you can't make the caraVAN), while the beta-lactams prevent cross-linking ("BET you can't CROSS your LACes")

Question 41

One common side effect of ondansetron is ______________.

Answer 41

headaches

Question 42

If a patient has yet to pass stool, what is a good way to distinguish volvulus and diverticular hemorrhage?

Answer 42

Volvulus is unlikely to lead to fever or leukocytosis, whereas diverticular hemorrhage can.

Question 43

What is First Aid's mnemonic for the spinal reflexes?

Answer 43

S1, S2: buckle my shoe (Achilles) L3, L4: kick the door (patellar) C5, C6: pick up sticks (biceps) C7, C8: lay them straight (triceps reflex) L1, L2: testicles move (cremasteric reflex) S3, S4: winks galore (anal wink reflex)

Question 44

True or false: give physostigmine to someone who's had an organophosphate overdose.

Answer 44

False. Give atropine and pralidoxime – more ACh will make organophosphate poisoning worse.

Question 45

Normally, dopamine inhibits the ________________.

Answer 45

putamen, which normally inhibits the Gpe;

Question 46

The Gpe normally inhibits the ______________.

Answer 46

subthalamic nucleus; without dopamine, the putamen is not inhibited and thus it over inhibits the Gpe; because the Gpe is supposed to inhibit the subthalamic nucleus, it fails to do so and thus the subthalamic nucleus inhibits the Gpi

Question 47

What are GI slow waves?

Answer 47

Rhythmic depolarizations and repolarizations of the GI tract that occur about every 20 seconds

Question 48

If a tRNA has a mutation that damages its hydrolytic site, what will occur?

Answer 48

Different amino acids will bind to that tRNA and then get incorporated where the original amino acid should have been.

Question 49

What is the mechanism of the antiviral that causes agranulocytosis?

Answer 49

Ganciclovir mimics dGTP and then inhibits viral DNA polymerase. (Think of the Gs: Ganciclovir = dGtp.)

Question 50

If a patient with AIDS has visual distortions, what infection should you be worried about?

Answer 50

CMV retinitis

Question 51

_____________ modulates the levels of IL-2 and is thus a great immunosuppressant.

Answer 51

Tacrolimus

Question 52

You know that macrolides bind to the 50S subunit, but what does it prevent?

Answer 52

Translocation of the tRNA subunits | Think of a CROw standing on a still LOCOmotive.

Question 53

What part of the lymph node houses T cells?

Answer 53

The paracortex