UWorld_2.10

Question 1

Valproate during pregnancy ==> ?

Answer 1

• neural tube defects due to inhibition of folic acid absorption @ intestine
  
  • meningocele, spina bifida, etc.

Question 2

Congenital coarctation of aorta association/presentation

Answer 2

• turner syndrome
• bicuspid aortic valve
• high BP proximal to coarctation (usually @ upper extremities) + low BP distal (usually @ lower extremities)

Question 3

Congenital duodenal atresia association + presentation

Answer 3

• Down’s syndrome
• presentation
  
  • bilous vomiting w/out abdominal distention on first day of life
  • peristaltic waves visible in abdomen
  • hx of polyhydramnios

Question 4

Congenital renal agenisis association + presentation

Answer 4

• Potter Syndrome
• Presentation
  
  • oligohydramnios
  • flattened facial features

Question 5

Ebstein’s anomaly association/presentation

Answer 5

• “Ebstein’s anomaly” = “atrialization” of R ventricle due to downward displacement of tricuspid valve
• associated w/mother use of lithium during early pregnancy

Question 6

Immunologic rxn to pulmonary TB

Answer 6

• CD4+ Th1 lymphocytes + macrophages contain TB w/in caseous granuloma

Question 7

Rabies encephalitis presentation

Answer 7

• generalized sx: malaise, anorexia, mild fever, HA, N/V
• agitation, disorientation
• pharyngospasm
• photophobia
• dysphagia + hypersalivation ==> “mouth foaming”
• rabies virus activates nicotinic acetylcholine receptors ==> sx

Question 8

Rabies virus characteristics

Answer 8

• ssRNA
• bullet-shaped capsule
• glycoprotein spikes bind nicotinic acetylcholine receptors
• begins as local infection, then binds ACh receptors on peripheral nerve to travel to CNS

Question 9

Viral cellular receptors:

CMV

EBV

HIV

Rhinovirus

Answer 9

• CMV = Cellular integrins
• EBV = CR2 (CD21)
• HIV = CD4 and CXCR4/CCR5
• Rhinovirus = ICAM1 (CD54)

Question 10

young male w/gait instability + pes cavus, kyphoscoliosis, hammertoes ==> dx?

Answer 10

Friedrich’s ataxia

Question 11

Characteristics/associations w/Friedrich’s ataxia

Answer 11

• AR
• Trinucleotide repeat on chromosome 9
• sx/associations
  
  • lower extremity ataxia, gait instability
  • skeletal abnormalities: pes cavus, hammertoes, kyphoscoliosis
  • hypertrophic cardiomyopathy ==> cardiac arrhythmias or CHF
  • DM may develop

Question 12

Results of immunoflourescence/light microscopy/EM in PSGN

Answer 12

• IF: granular deposits of IgG, IgM, and C3 @ mesangium and GBM
• LM: hypercellular glomeruli = PMNs, macs, prolif of mesangium/endothelium
• EM: supepithelial humps = deposition of antibody-antigen complexes

Question 13

Damage to radial nerve ==>

Answer 13

• “wrist drop” = fingers cannot be extended

Question 14

Damage to median nerve ==>

Answer 14

• limited hand flexion
• limited opposition of thumb

Question 15

Holosystolic murmur that increases in intensity on inspiration ==> dx?

Answer 15

Tricuspid regurgitation

Question 16

Pathogenesis of atherosclerosis

Answer 16

1. chronic injury/inflammation ==> endothelial cell injury ==> increased endothelial cell permeability/dysfxn +/- exposure of subendothelial collagen
   
   1. increased perm ==> mac/lymphocyte migration into vessel walls + LDL cholesterol ==> foamy (lipid-laden) macrophages
      
      1. macrophages/lymphocytes ==> maintenance of inflammation + migration/proliferation of SMCs into intima
   2. subendothelial exposure ==> promotion of platelet aggregration
2. eventually, formation of collection of foamy macs w/necrotic core surounded by fibrous cap + SMCs

Question 17

Low disease prevelance impacts which biostatistical measure of a binary (P or N) diagnostic test?

Answer 17

Positive Predictive Value