Functional renal anatomy and contrast media

Question 1

What is the blood supply and chain in the kidney?

Answer 1

Main renal artery
Interlobar artery
Arcuate artery at corticomedullary junction
Interlobular artery
Affarent arteriole

Question 2

Why is the kidney good at regulating GFR and renal blood flow despite changes in blood volume or pressure?

Answer 2

Because it is sandwiched between two resistive capillary networks

Question 3

What is the macula densa? What is the juxtaglomerular apparatus?

Answer 3

Tubular component of the juxtaglomerular apparatus, which is the site of renin synthesis. Between ascending loop of henle and distal convoluted tubule

Question 4

What is meant by the term clearance?

Answer 4

rate at which a substance is removed from the plasma

Question 5

What is the main cause of toxicity in contrast agents?

Answer 5

Osmolality

Question 6

What are the two low osmolarity classes of contrast agent?

Answer 6

1 - nonionic monomers. Hydrophilic nonionizing radicals that dont dissociate, increasing the ratio of iodine to particles in solution to 3 from 1.5 (omnipaque)

2 - monoacidic dimers - 6 iodine atoms to one particle (visipaque)

Question 7

What is vicarious excretion?

Answer 7

Excretion of contrast via the biliary tract or small bowel

Thought to be due to protein binding of the contrast medium that is then expelled via hepatic excretion

Question 8

What is the relationship between temperature and viscosity?

Answer 8

Raising temperature decreases viscosity

Question 9

what is the relationship between sex and contrast reaction?

Answer 9

Females more commonly have a reaction but males are more often fatal

Question 10

Is there a relationship between dose and incidence of contrast reaction?

Answer 10

Only for severe reactions, and only if >20g

Question 11

Which has a lower rate of contrast reaction? IV or IA

Answer 11

IA by 1/2

Question 12

What is iodism?

Answer 12

acute reaction to iodine itself characterized by sialadenitis, diarrhea, and pulmonary edema

Question 13

Which type of contrast, HOCM or LOCM should be used in angiography?

Answer 13

HOCM

LOCM has less anticoagulant effect and can cuase clots

Question 14

What is the initial treatment for contrast extravasation?

Answer 14

Elevate extremity
Ice packs
Close obs

Question 15

When to get a plastic surgery consult for contrast extravasation?

Answer 15

>30 ionic or >100mL nonionic
skin blistering
Altered tissue perfusion
Increasing pain
Loss of pulse of numbness

Question 16

What is the relationship between contrast and metformin?

Answer 16

Metformin is renally excreted, and it is thought that those with renal issues or getting contrast will have a slower excretion and thus higher rate of lactic acidosis.

Free to take up to exam, but hold 48hrs until renal function normalizes

Question 17

does dose play a role in adverse contrast reactions?

Answer 17

yes

Question 18

what is the most effective way to prevent acute renal dysfunction follwoing contrast?

Answer 18

IV hydration, sodium bicarb has been shown to help as well

Question 19

What is the treatment for bronchospasm and laryngeal edema? if subq vs iv?

Answer 19

Subq - 1:1000 epinephrine 0.3-0.5mL

IV - 1:10000 3-5mL