3/23 UWORLD test # 62

Question 1

Q 2. What general class of molecule cause of acute interstitial nephritis? examples of this molecule? (5)
(hint: remember

Answer 1

drugs that work as haptogens

five Ps
Pee (diuretics)
Pain (NSAIDs)
Proton pump inhibitor
Penicilin, cephalosporins, also sulfonamide
rifamPin

Question 2

Q 2. Which hypersensitivity reaction mediates acute interstitial nephritis?

Answer 2

IgE mediated or even type 4

Question 3

Q 2. What is treatment of acute interstitial nephritis?

Answer 3

AIN resolves almost simultaneously after withdrawal of offending reagents

Question 4

Q 3. Which cell is main site for collagen synthesis? In what intracellular organelle of this cell?

Answer 4

fibroblast

rough ER (collagen will be exported to outside of cell essentially)

Question 5

Q 3. which amino acid is most rich in collagen? (That is, which amino acid content best reflects collagen synthesis?)

Answer 5

glycine

Question 6

Q 4. parasympathetic innervation on detrusor muscle?

Answer 6

contraction
remember: detrusor is surrounding muscle of bladder

• don’t get confused with trigon or

Question 7

Q 4. parasympathetic innervation with vasoconstriciton or vasodilation? mechanism?

Answer 7

parasympathetic system INDIRECTLY mediates vasodilation by releasing NO

• If none of answer choices make sense for parasympathetic mediated response, pick vasodilation

Question 8

Q 6. Define “permissiveness” between two drugs. What is example of permissiveness?

Answer 8

Effect of one drug becomes limited, but addition of another drug intensify the effect of first drug.
second drug does NOT have drug effect by itself
(vs. additive effect or synergistic effect)

ex: beta agonist + thryoid hormone.
=> thyroid hormone increases beta receptor availability, intensifying effect of beta agonist. thyroid hormone itself does not increase beta adrenergic effect

Question 9

compare additive effect vs. synergistic effect between drugs

Answer 9

• additive effect: sum of two drugs is equal to addition of individual drug
• synergistic effect- sum of two drugs is greater than addition of individual drug

Question 10

Q 8. Recurrent kidney stone, bitemporal visual field defect. What another cancer may be present?

Answer 10

pancreatic cancer

MEN1 !!

• this question is good one: If question seems to present MORE THAN TWO CANCERS, always think about MULTI ENDOCRINE NEOPLASIA

Question 11

Q 12. How Hartnup disease is associated with niacin deficiency? inheritance pattern of Hartnup disease?

Answer 11

autosomal recessive

Hartnup disease:
PCT aminoacid transport is messed up
-> impaired amino acid reabsorption
-> waste of tryptophan -> niacin deficiency

Question 12

Q 13. What if filter implantation for DVT? where is filter normally placed?

Answer 12

Filter is placed in IVC to prevent propagation of thrombi from DVT to pulmonary ciculation

Question 13

Q 14. How mycoplasma infection can cause anemia? what kind of anemia? how this anemia can resolve?

Answer 13

mycoplasma triggers cold agglutinins (IgM), which binds to RBC and lyse it. (cold aggultination test can be performed to diagnosis of mycoplasma infection)

=> hemolytic anemia

as immune response fades (that is, cold IgM goes away), anemia resolves

Question 14

Q 15. what three major muscles are used for sitting up from supine position?

Answer 14

• external abdominal obliques
• rectus abdominis
• hip flexors (ilopsoas = iliacus + psoas)
• SIT UP is not same as STAND UP

Question 15

Q 16. African american, acute chest pain and abdominal pain that resolves with hydration with some weird thing going on spleen. What should be in differential diagnosis?

Answer 15

sickle cell disease

• acute chest pain is one of many manifestations of vaso-oclusive crisis. also called as acute chest syndrome
• dehydration is also cause of sickling. In fact, hydration is one of treatment options for sickle cell disease (as well as hydroxyurea)

Question 16

Q 17. Describe histologic finding of epidermis of eczema (atopic dermatitis)

Answer 16

intraepidermal vesicles

=> spongiosis, epidermal fluid accumulation of edematous fluid

Question 17

Q 17. What happen to skin after topical corticosteroid therapy for atopic dermatitis? explain mechanism

Answer 17

dermal atropy

corticosteroid can decrease extracellular matrix collagen

Question 18

Q 18. What are two arteries branching off from splenic artery? which artery is susceptible

Answer 18

short gastric and left gastroepiploic

short gastric artery does not have anastomosis
=> susceptible for ischemic injury after splenic artery rupture.

L. gastroepiploic artery anastomoses with R. gastroepiploic

Question 19

Q 19. What is target of isoniazid?

Answer 19

mycolic acid synthesis

Question 20

Q 21. What electrolyte imbalance should be considered with succinylcholine? what serious complication is caused by this electrolyte imbalance?

Answer 20

hyperkalemia -> cardiac arrhythmia

succinylcholine is depolarizing muscle relaxant.
constant depolarization => hyperkalemia

Question 21

Q 22. What is renal compensation to high altitude sickness? Within how many hours will renal compensation occur?

Answer 21

high altitude -> respiratory alkalosis

renal excretion of HCO3- (or decreased renal HCO3- reabsorption) to compensate
compensation occurs usually within 24-48 hrs

Question 22

Q 23. Mass in lymph node. What needs to be checked to ensure that this mass is malignant?

Answer 22

key difference between simple hyperplasia and neoplasia is that hyperplasia is polyclonal expansion, while neoplasia is monoclonal expansion

• according to pathoma,
  relative amount of Ig light chain isoforms (kappa:lamda) is normally 3:1. But in neoplasia ratio can bump up to 6:1, indicating monoclonal expansion.
• Pathoma p.23 extensively covers this topic

Question 23

Q 25. Pathophsiology of gait ataxia in Friedrich ataxia?

Answer 23

degeneration of spinocerebellar tract and lateral corticospinal tract

Question 24

Q 27. Key difference between atopic dermatitis and dermatitis herpitiformis? what about similarity?

Answer 24

key difference is onset age

• atopic dermatitis: common in all age
• dermatitis herpiformis: as a complication of celiac, it happens at 40-50 age.

Both presents as pruritic rash

Question 25

Q 28. marker of cells surrounding caseating granuloma in TB

Answer 25

epitheloid macrophage surrounds granuloma

CD 14 is marker of marcrophages

Question 26

Q 30. What is prognostic factor for PSGN?

Answer 26

age of onset

kids with PSGN usually completely recover for >95% cases, while adults completely recover for only 60%

Question 27

Q 31. which medication can precipitate side effect of lithium? why?

Answer 27

thiazide

thiazide -> decreased GFR (due to less water coming in kidney after volume loss) -> decreased renal clearance of lithium

• sketchy: guy on the top of diving pole that says low clearance on left top corner

Question 28

Q 33. porcelain gallbladder

• possible cause
• imaging finding
• increased risk for what?

Answer 28

• chronic cholecystitis
• calcification along gallbladder WALL
• gallbladder adenocarcinoma

Question 29

Q 34. increased ALP indicates what two types of pathology. After increased ALP, what serum marker would be useful as a follow up? why?

Answer 29

• ALP can be marker for pathology of
  1. bone: pagets, osteomalacia, osteitis fibrosa cystica (primary/secondary hyperparathyroidism)
• anytime u need to make more bone due to bone destruction- EXCEPT OSTEOPOROSIS, where all values are normal
  2. liver: cholestasis
• After increased ALP is detected, gamma-glutamyl transpeptidase can be used as a follow up. gamma-glutamyltranspeptidase is not seen in bone disease.
  it is seen only for liver.

Question 30

Q 37. What hematologic malignancy can present mediastinal mass? what would be physical exam findings (3)

Answer 30

Acute lymphoblastic T cell leukemia

• mediastinal mass -> dysphagia, stridor, SVC syndrome like presentation (flushing, facial edema)