UWorld_4.7

Question 1

Anti-arrhythmics with use-dependence

Answer 1

• class I – esp. class IC

Question 2

Verapamil: MOA, use, SE

Answer 2

• MOA: non-dihydropyrimadine Ca2+ channel blocker
  
  • more specificity to heart vs. nifedipine
  • slows conduction through AV node
• use: Afib with reentrant
• SE
  
  • constipation
  • gingival hyperplasia
  • AV node block

Question 3

PMNT purpose and control

Answer 3

• PMNT = phenylethanolamine-N-methyltransferase
• synthesizes Epi from NE
• under control of cortisol ==> increased gene expression of PMNT

Question 4

Anti-metabolite drugs

Answer 4

• folate antagonist
  
  • methotrexate
• purine analogs
  
  • thiopurines (6-MP, 6-GP
  • Fludarabine ==> CLL
  • Cladribine ==> HCL
    
    • adenosine analog resistant to adenosine deaminase
• pyrimadine analogs
  
  • 5-FU
  • Capecitabine
  • Cytaribine
  • Gemcitabine

Question 5

Most common cause of native valve endocarditis

Answer 5

• mitral valve prolapse
• rheumatic fever possible, but less common in US due to tx of Strep A with antibiotics

Question 6

Most important pathogenic mechanism for shigella

Answer 6

• 1. mucosal invasion
• 2. exotoxin ==> increased virulence + HUS [but not most important]

Question 7

Characteristics of PBC

Answer 7

• autoimmune destruction of liver bile ducts + cholestasis
• usually @ middle-aged women, insidious onset
• initial sx: pruritis and fatigue
• progression: jaundice, steatorrhea, portal HTN, osteopenia
• PE: hepatosplenomegaly and evidence of cholestasis (xanthelasma, pale stool)

Question 8

Cause of cutaneous flusing with niacin + tx

Answer 8

• due to prostaglandin release
• tx = pretreat with aspirin

Question 9

Bioavailability calculation

Answer 9

F = (AUC oral x IV dose)/(AUC IV x oral dose)

Question 10

Patients for whom ACE-i are contraindicated

Answer 10

bilateral renal artery stenosis/renal artery stenosis + atherosclerosis

Question 11

Main antiviral agent that does not require intracell phosphorylation to be active

Answer 11

foscarnet

Question 12

Polyethylene glycol laxative type? + similar disease process

Answer 12

• osmotic laxative
• also – MgOH
• lactase deficiency ==> osmotic diarrhea

Question 13

Anti-arrhythmics that ==> QT prolongation

Answer 13

• quinidine
• procainamide
• disopyramide
• ibutilide
• defetilide
• sotalol

Question 14

Beurger’s disease

Answer 14

• vasculitis in smokers; aka thromboangiitis obliterans
  
  • rxn to injected tobacco extract
• small-medium vessel vasculitis; mostly @ tibial and radial arteries
• histo = acute+ chronic inflammation; segmental thrombosis can extend into contigous veins and nerves

Question 15

_____ ==> similar presentation to Friedrich Ataxia

Answer 15

vit E deficiency