UWorld_3.17 Flashcards Preview

USMLE Step 1 > UWorld_3.17 > Flashcards

Flashcards in UWorld_3.17 Deck (34)
1

Blood testing in suscipicion of celiacs

  • blood test for:
    • IgA anti-endomysial
    • Iga anti-tissue transglutaminase

2

Transmural inflammation of arteries w/fibrinoid necrosis ==> dx?

  • polyarteritis nodosa

3

Characteristics of polyarteritis nodosa

  • segmental, fibrinoid necrosis of small-med arteries
  • Sx
    • fever
    • abdominal pain
    • peripheral neuropathy
    • weakness
    • weight loss
  • assoc. w/hep B in 10-30% of cases

4

Most common point of occurence of intusseception

ileocecal jxn

5

Characteristics of a transaminase reaction

  • reaction between amino acid and an alpha-keto acid
    • e.g. glutamate & oxaloacetate
  • often occur to allow amino acids to enter TCA cycle/Urea cycle
  • Vit B6 (Pyroxidine) = cofactor for transaminase and decarboxilation reactions

6

TH1 cytokines (+ purpose) =

TH2 cytokines (+ purpose) = 

  1. interferon-gamma, IL-2 ==> activate macs & attract CD8+ t cells
  2. TH2 ==> stimulate B cells [adaptive immunity]
    1. IL4 + IL13 ==> IgE from B cells
    2. IL5 ==> IgA + eosinophil

7

"Red neurons" on histo section of brain

  • ischemia/infaction within the past 12-24 hrs

8

Characteristics of lynch syndrome

  • hereditary nonpolyposis colon cancer
  • due to defect in mismatch repair 
  • AD
  • due to mutations @
    • MSH2 ==> MutS
    • MLH1 ==> MutL

9

a. that runs with the radial n.

deep brachial 

10

anatomic structure that runs through the hepatoduodenal ligament

  • portal triad = hepatic artery, portal vein, common bile duct

11

Mechanism of relaxation of cardiac muscle

  • calcium efflux preceeds relaxation
  • accomplished via:
    • Ca2+ ATP pump
    • Na/Ca exchanger

12

Most common cause of bronchiolitis + tx

  • RSV
  • 1st line = O2 or IV fluids
  • in @ risk for progression, can give ribavirin:
    • nucleoside analog
    • active against RSV and hep C

13

K+ in DKA

  • total body decrease in K+
  • decreased intracell stores of K+
  • normal to increased serum K+
    • K+ drawn out in exchange for H+; low insulin levels
    • increased if hypovolemic

14

HCV vs. HBV most common transmission

  • HCV 
    • most common = blood transfusion or IV drug use
    • possible, but less common = sexual transmission
  • HBV
    • blood contact (transfusion, needle stick, IV drug use) OR unprotected sex

15

Strep infections that lead post-strep syndromes

  • Impetigo (step skin infect) OR strep pharyngitis ==> APSGN
  • ONLY strep pharyngitis ==> rheumatic fever

16

Common cause of fluid filled cavity in liver + fever chills

  • dx = hepatic abcess
  • underdeveloped countries ==> parasitic infection (entamaeba histolytica)
  • developed countries ==> bacterial infection
    • biliary tract infection (asc. cholangitis)
    • portal vein pyremia (bowel or peritoneal sources e.g. appecitis, peritonitis, enteric pathogens)
    • hepatic artery (hemat spread from distant site)
    • penetrating injury or trauma

17

ST elevation @ V1-V3 ==> dx?

occlusion at left anterior descending coronary artery

18

Riboflavin biochemical role

  • Riboflavin + Pi ==> FMN = coenzyme
  • FMN + Pi ==> FAD (i.e. FAD+) ==> oxidation/reduction reaction
    • e.g. @ TCA cycle: succinate + FAD+ ==> fumarate + FADH2

19

Palpaple, nontender gallbladder + jaundice ==> dx?

  • palpable, nontender gall = "Courvosier's sign" 
  • dx = adenocarcinoma of the head of the pancreas obstructing CBD  

20

Presentation and risks for adenocarcinoma of the head of the pancreas

  • ==> courvosiers sign (palpable, distended, nontender gallbladder) + anorexia + obstructive jaundice
    • obstructive jaundice = jaundice + dark urine + pale stools
  • risks
    • age > 50
    • smoking
    • DM
    • chronic pancretitis
    • genetic predisposition: HNP, FAP, MEN

21

Ondansetron: MOA, use

  • MOA
    • central =  5HT3 inhibitor @ chemoreceptor trigger zone (medulla) & solitary nuceus
    • periphery = inhibit vagus-mediated nausea
  • use: post-chemo anti-nausea

22

5HT3-inhibitors

  • ondansetron
  • granesetron
  • dolasetron

23

Rapid and complete relief in RA [short-term]

glucocorticoids, e.g. prednisone

24

Methotrexate: MOA, use

  • MOA: antimetabolite, antifolate
  • use: RA, other autoimmune

25

Auer Rods ==> dx?

  • AML (/PML)

26

Nevirapine: MOA, similar drugs

  • NNRTI
  • inhibits reverse transcription, doesn't need phosphorylation to be active
  • other drugs
    • efavirenz
    • delaviridine

27

Canagiflozin: MOA, use, SE

  • MOA
    • oral anti-diabetic
    • = SGLT2 inhibitor ==> decreased reabsorption of glucose @ proximal renal tubule
    • ==> urinary glucose loss
  • SE
    • renal effects <== monitor Creatinine and BUN

28

Lithium toxicity antidote

hydrocholorthiazide ==> trapping in urine

29

Cause of decreased gene transcription in Huntington's

  • CAG repeats ==> gain of fxn ==> pathologic interactions w/trxn factors
  • abnormal huntingtin ==> histone deacetylation ==> repressed trxn ==> decreased production of neurotrophic factors ==> impaired neuron survival 

30

Causes of polyhydramnios

  • decreased fetal swallowing
    • intestinal atresia/obstruction
    • anencephaly
  • increased urine production
    • twin-twin transfusion
    • high CO due to anemia

31

Enhancer and inhibitor of morphine/opoid tolerance

  • mechanism = ~ phosphorylation of receptors, increased cAMP 
  • glutamate ==> increased NMDA receptor activity ==> potentiation of tolerance
  • ketamine ==I tolerance

32

RANK receptor fxn

  • ==> formation and differentiation of osteoclasts ==> increased bone resorption
  • ligands for RANK receptor = 
    • RANK ligand <== osteoblast-produced
    • MSC <== osteoblast produced
  • bone formation regulated by RANK/OPG (osteoprotegerin) balance
    • OPG also produced by osteoblasts 

33

Location of PTH receptors in bone marrow

osteoblasts

34

Ras protein type & association

  • part of MAP kinase pathway ==> cell growth and differentiation
  • G protein; activated by GTP

Decks in USMLE Step 1 Class (97):