UWorld_3.16

Question 1

How long till continuous infusion or drug reaches steady state?

Answer 1

• IF: continuous infusion + elimination via first-order kinetics ==>
• steady state plasma concentration @ 4-5 half lives

Question 2

Stages of arrest of oocytes

Answer 2

• @ fetus: oocytes progress ==> prophase I and are arrested until ovulation
• @ ovulation: oocytes progress ==> metaphase II and first polar body released until fertilization

Question 3

t(15:17)

Answer 3

• AML
• retinoic acid receptor (17) placed next to PML gene on 15
  *

Question 4

Giardia pathogenesis & immune response

Answer 4

• Giardia attaches to intestinal brush border + release toxins ==> inflammation and diarrhea
• Secretory IgA prevents adherence <== most important immune response in combating Giardia
  
  • CD4+ helper T cells also involved in combating infection

Question 5

Presentation of ethylene glycol toxicity

Answer 5

• ethylene glycol metabolized ==> glycolic acid & oxalic acid
• anion-gap metabolic acidosis
• calcium oxalate crystals in urine
• increased osmolar gap
• acute kidney injury/renal failure
  
  • damage to tubular epithelium
    
    • vacuolization
    • ballooning

Question 6

Characteristics of AFib rhythm

Answer 6

• absent P waves
• narrow QRS complexes
• irregularly, irregular R-R intervals
• repeated/frenetic electrical impulses through atria that lead to inneficient contraction of the atria
• ventricles contract after electrical impulse passes through AV node
  
  • AV node refractory period determines rate/number of electrical impulses from artria that result in contraction of the ventricles

Question 7

Common cause/consequences of long thoracic nerve injury?

Answer 7

• mastectomy
  
  • or any trauma to the axilla area
• ==> paralysis of serratus anterior
  
  • ==> winging of scapula
  • ==> inability to abduct arm above horizontal

Question 8

Presentation of theophylline toxicity + tx

Answer 8

• theophylline ==>
  
  • N/V + abdominal pain
  • arrhythmias
  • seizures **
• Tx
  
  • gastric lavage
  • activated charcoal
  • cathartics (increase elimination via GI tract)
  • beta-blockers ==x arrhythmias
  • benzodiazepines & baribituates ==x seizures

Question 9

Lithium: indications, side effects

Answer 9

• bi-polar; manic and depressive episodes, maintenance
• SE
  
  • DI
  • tremor
  • hypothyroidism
  • Epstein’s anomaly

Question 10

Valproate: indications, SE

Answer 10

• manic episodes; maintence in bipolar & generalized/absence/myclonic seizures
• SE
  
  • hepatotox
  • NTDs

Question 11

Carbamazepine: indications, SE

Answer 11

• manic episodes, maintence
• partial generalized seizures
• trigeminal neuralgia
• SE
  
  • agranulocytosis
  • NTDs
  • hyponatremia (SIADH)

Question 12

Lamotrigine: indications, SE

Answer 12

• depressive episodes, maintenance in bipolar
• focal seizures
• SE
  
  • stevens-johnson
  • benign rash

Question 13

Mood stabilizers in bipolar

Answer 13

• lithium
• valproate
• carbamazepime
• lamotrigine

Question 14

Lab test: mix serum w/cholesterol, lethicin, and cardiolipin ==> flocculation?

Answer 14

• test looking for antibodies to cardiolipin <== released in to serum after cellular destruction of Treponema species
• indicates possible Syphillis infections

Question 15

Sepsis/shock ==> pulmonary problems?

Answer 15

• ARDS = fluid accumulation @ alveoli

Question 16

Pathophys ==> wedge-shaped necrosis @ lung?

Answer 16

pulmonary embolus

Question 17

Ornithine role in cellular metabolism

Answer 17

• involved in the urea cycle
• ornithine transported into mitochondria in oder to help break down ammonium
• defect in ornithine ==> problems with protein metabolism

Question 18

Child w/gray pharyngeal exudates + cervical lymphadenopathy ==> dx + mechanism

Answer 18

• Corynebacterium diptheria
  
  • gram + bacillus
• diptheria toxin = AB exotoxin ==> inactivation of EF2 via ADP-ribosylation = interrupted protein synthesis ==> pseudomembrane formation

Question 19

Prevention and complications of diptheria infection

Answer 19

• prevention = vaccine w/diptheria toxoid
• complications
  
  • suffocation due to colonization/pseudomembrane
  • neurotoxicity
  • myocarditis/heart failure

Question 20

Cell types that contain telomerase

Answer 20

• stem cells
  
  • e.g. epithelial basal cells
  • e.g. gastric lining stem cells
  • e.g. bone marrow stem cells
• cancer cells

Question 21

Micro characteristics of Legionella

Answer 21

• intracell motile gram (-) rod
• weakly stains with gram stain, silver stains improve visualization
• grows on buffered charcoal yeast extract agar w/ supplemation by L-cysteine and iron

Question 22

Use/Effects:

Physostigmine vs. Neostigmin vs. Edrophonium

Answer 22

• all AChE inhibitors
• use = reverse atropine toxicity
• neostigmine/edrophonium = only fxn @ peripherphy; cannot penetrate CNS
• physostigmine = fxns @ periphery & CNS

Question 23

Etanercept: MOA, SE

Answer 23

• MOA = TNF-a inhibitor
  
  • used in mod/sever RA, esp. @ patients who have failed methotrexate
• SE
  
  • can reactivate latent TB infection <== PPD skin test for latent TB

Question 24

Adverse effects of thionamides (antithyroid drugs)

Answer 24

• ==> agranulocytosis
• methimazole: teratogen; cholestasis
• propthiouracil: hepatic toxicity; ANCA-assoc. vasculitis

Question 25

Adverse effects of:

radioactive ablation of thyroid

thyrectomy

Answer 25

• radioiodine
  
  • permanent hypothyroid
  • worsening opthalmo
  • radiation se
• surgery
  
  • permanent hypothyroid
  • recurrent laryngeal nerve injury
  • hypoparathyroidism

Question 26

Characteristic’s of Friedrich’s Ataxia

Answer 26

• trinucleotide repeat; AR; gene locus on chromosome 9
• abnormal mitochondrial fxn ==> degeneration of spinal tracts and peripheral nerves
• spincerebellar tracts degen ==> abnormal gait
• dorsal degen ==> loss of vibration/position
• kyphoscoliosis & foot abnormalities
• hypertrophic cardiomyopathy ==> heart failure
• DM

Question 27

calories in 1g protein, carb, fat

Answer 27

• 1 g carb or protein = 4 cal
• 1 g fat = 9 cal