NBME/UWorld 3

Question 1

Clinical presentation of hyper vs. hypocalcemia

Answer 1

Hypercalcemia: moans (constipation), bones (bone pain), stones (kidney stones), psychiatric overtones (depression confusion), cant pick up the phone (muscle weakness and incoordination)

While tetany, spasms, seizures, Chvostek and Trousseau’s signs = hypocalcemia

Question 2

Cvostek’s sign

Answer 2

HypOcalcemia: gently tapping facial nerve => reflex contraction of facial muscles

Question 3

Name of immunomodulatory used in IBD that is less immunosuppressive than prednisone

Answer 3

Sulfasalazine

Question 4

La belle indifference

Answer 4

Buzzword for Conversion d/o- usually loss of sensory or motor fxn

Question 5

Conversion d/o vs. somatization d/o

Answer 5

Conversion d/o: sensory or motor loss, la belle indifference

Somatization d/o: recurrent widespread somatic complaints w/o any abnormal tests, seen tons of doctors w/o diagnosis

Question 6

Precentral vs. postcentral gyrus

Answer 6

Precentral gyrus = motor

Postcentral gyrus = sensory

Question 7

Leukocyte alkaline phosphatase

Answer 7

Leuk alk phos indicates mature WBC

Elevated leukocyte alk phos in myelodysplastic conditions, while reduced in AML

Question 8

What is factor H?

(a) Protien that inhibits factor H

Answer 8

Factor H = anti-complement, inactivates C3

(a) Properdin = factor P = activates C3 and inhibits factor H, involved in acute immune responses such as acute rejection of blood transfusion

Question 9

Weakness of what thumb activity 2/2 carpel tunnel

Answer 9

Median nerve injury => weakness in thumb opposition

'RUM'
Thumb extension (parallel movement away from pointer finger) mediated by radial nerve
Thumb flexion (bring back in towards pointer finger) by ulnar nerve
Thumb opposition (thumb to pinki) by median nerve

Question 10

What are anaphylaxtoxins?

Answer 10

Anaphlatoxins = C3a C4a and C5a = fragments produced by activation of complement

Question 11

Folate vs. B12 deficiency

Answer 11

Both have elevated homocysteine => hypercoagulable

Elevated uric MMA only in B12

Question 12

pH abnormality caused by diarrhea

Answer 12

Metabolic alkalosis 2/2 loss of salts of organic acids

Question 13

2 major functions of PGI2

Answer 13

PGI1 = prostacyclin

1. inhibits plt aggregation
   - opposite of another eicosanoid TXA2
2. effective vasodilator

Question 14

Ion flux that causes seizure to stop when pt is given Lorazepam

Answer 14

Increased influx of Cl-

-recall GABA is a Cl channel and benzos increase frequency of opening

Question 15

Mechanism by which ACEi cause vasodilation

Answer 15

ACEi cause vasodilation due to decreased degradation of bradykinin

(also why ACEi cause dry cough)

Question 16

2 mutations that cause acyclovir-resistant HSV

Answer 16

1. DNA polymerase mutation

2. Thymidine kinase which is a viral enzyme needed to do to the first phosphorylation to activate acyclovir

Question 17

External and internal genitalia present if SRY gene is missing

Answer 17

No SRY gene = no testes develop =>

• no Leydig cells => no testosterone => no male external genitalia
• no Sertoli cells => no anti-Mullerian hormone => female internal genitalia doesn’t degenerate

So get full female both internal and external

Question 18

Contrast clinical presentation of mutated SRY gene vs androgen insensitivity

Answer 18

Mutated SRY gene = female external and internal genitalia b/c no T and no anti-MF

Androgen insensitivity = female external genitalia but vagina leads to blind-pouch b/c anti-MF is present (testes and Sertoli cells develop properly) so female internal genitalia degenerates

Question 19

On angiography there is 50% stenosis of a coronary artery, by what fraction is flow reduced

Answer 19

Flow relative to radius ^4

So flow reduced by 16x

Question 20

Defect in what structure allows hydrocele

Answer 20

Defect in processus vaginalis (not tunica albiguinea which is the serosa surrounding testes after processus vaginalis fuses) allows for formation of both hydrocele and indirect inguinal hernia