Mix2

Question 1

If a patient presents with recurrent diarrhea, cutaneous flushing, wheezing, and tricuspid regurg (R sided valvular heart Dz) then what is the most likely Dx?

Answer 1

Carcinoid Syndrome

This is a metastatic small bowel tumor that secretes high levels of 5HT.

Question 2

Aside from surgery, how would carcinoid syndrome be treated?

Answer 2

Admin of octreotide (SS analog)

Question 3

What’s the role of cabergoline in treating GH secreting pituitary tumors?

Answer 3

Cabergoline = dopamine agonist.

** Can also be used to treat prolactinomas.

Question 4

Leuprolide is a synthetic analog of:

Answer 4

GnRH

Question 5

Pheochromocytoma is the most common tumor of the adrenal medulla in adults. It is derived from what cell type?

Answer 5

chromaffin cells (from neural crest)

Question 6

What is the MOA of using phenoxybenzamine in treating pheochromocytoma?

Answer 6

Phenoxybenzamine is an irreversible alpha antagonist.

** Should give a-antagonist followed by B-blocker. Alpha block must be achieved before giving beta blocker to prevent hypertensive crisis.

Question 7

Since both E coli and Enterobacter cloacae are both G(-) lactose fermenting bacilli, how could you distinguish them in a case of UTI?

Answer 7

Can check for indole positivity. E coli = indole pos (+)

Indole positivity = ability to convert tryptophan to indole

Question 8

The omphalomesenteric (vitelline) duct connects the midgut lumen with the ___ in early fetal life. It normally obliterates during the ___ week of development.

Answer 8

yolk sac, 7th week

Question 9

What event at birth could indicate that the vitelline duct has failed to close?

Answer 9

Passage of meconium discharge from the umbilicus soon after birth.

Question 10

___ is a defense mechanism in which an individual transforms unacceptable feelings or impulses into their extreme opposites:

Answer 10

reaction formation

Question 11

What are the 4 major structures contained in the carpal tunnel?

Answer 11

1. flexor digitorum profundus tendons
2. flexor digitorum superficialis “
3. flexor pollicus longus tendon
4. median nerve

Question 12

The sciatic nerve is derived from ___ branches but compression most often occurs at ___

Answer 12

L4-S3. Compression at L5 or S1 (via vertebral disc herniation)

Question 13

What electrolyte disturbances can be caused by foscarnet use?

Answer 13

Foscarnet = pyrophosphate analog (binds PP site on viral DNA polymerase) that is used for acyclovir resistant CMV.

Foscarnet chelates Ca2+, induces renal Mg2+ wasting, and causes release of PTH. End result is hypocalcemia and hypomagnesemia&raquo_space; SEIZURE

Question 14

What are the 2 major toxicities assoc with acyclovir use?

Answer 14

1. Obstructive Crystal nephropathy&raquo_space; renal failure

2. Neurotoxicity (delirium and tremor)

Question 15

What infection is acyclovir predominantly used to treat and what is the MOA?

Answer 15

Acyclovir = guanosine analog&raquo_space; inhibition of viral DNA Pol&raquo_space; chain termination

Used to treat HSV/VZV. Monophosphorylated by HSV/VZV thymidine kinase (so few adverse effects in uninfected cells)

Question 16

What infection is sofosbuvir predominantly used to treat and what is the MOA?

Answer 16

Sofosbuvir = inhibits HCV RNA dependent RNA polymerase (NS5B) and acts as a chain terminator.

Generally used in combination therapy with ribavirin, simeprevir, and ledipasvir for chronic HepC infection.

Question 17

What infection is ganciclovir predominantly used to treat and what is the MOA?

Answer 17

Ganciclovir = Guanosine analog (5’monophosphate). Preferentially inhibits CMV viral kinase (viral DNA polymerase)

Question 18

What are 3 common first line meds for bipolar maintenance therapy?

Answer 18

Lithium
Valproate (anticonvulsant)
Quietapine (2nd gen antipsychotic)

** Lamotrigine (another anticonvulsant) can be used in maintenance Rx for preventing depression in bipolar.

Question 19

Methylphenidate is used to treat what psychiatric condition?

Answer 19

ADHD. Methylphenidate is a psychostimulant.

Question 20

Why can’t cephalosporins be used to treat Listeria infections?

Answer 20

Cephalosporins = block PBP (penicillin binding protein)

Listeria is motile and a facultative intracellular organism so it is able to avoid phagocytosis and can spread intracellularly. Listeria is resistant to cephalosporins because it has an altered PBP. It is still sensitive to ampicillin though.

Question 21

What’s the rate limiting step in the pentose phosphate pathway?

Answer 21

G6PD. Catalyzes conversion of G6P to 6-phosphogluconate

PPP is used to generate NADPH and ribose5-P (nucleotide synth precursor).

IF NADPH isn’t produced, glutathione can’t be reduced, cell suffers free radical damage&raquo_space; hemolysis

Question 22

Why are the elderly predisposed to UTI?

Answer 22

Urinary obstruction (BPH), fecal incontinence, neurogenic bladder (due to DM), and frequent or indwelling catheterization.