Session 2- Clearance

Question 1

Normal GFR?

Answer 1

90-120ml/min

Question 2

GFR in pregnancy?

Answer 2

50% increase, 130-180ml/min

Question 3

Who can grow new nephrons?

Answer 3

Children

Question 4

What do adults do instead of making new nephrons?

Answer 4

Compensatory hypertrophy

Question 5

After age 30 how much does GFR decline per year

Answer 5

6ml/year

Question 6

What is eGFR appropriate for measuring?

Answer 6

CKD

Question 7

What is eGFR not appropriate for?

Answer 7

In pregnancy, AKI, children/elderly, GFR >60ml/min

Question 8

What does eGFR account for

Answer 8

Age, sex, black

Question 9

Problem with creatinine?

Answer 9

Individual variation- if more muscly make more creatinine
Diet- eat more meat then more creatinine
Secretion- some actively secreted in PCT so GFR is overestimated by 10%

Question 10

What’s good about creatinine?

Answer 10

Endogenously made (unlike inulin), not reabsorbed, freely filtered at glomerulus

Question 11

What GFR measure can you use for children or renal transplant?

Answer 11

51 Cr-EDTA- radioactive, inject, 3 bloods.

Question 12

Creatinine secretion ________ with worsening GFR

Answer 12

Increases (so underestimates renal failure)

Question 13

Using creatinine _______ GFR

Answer 13

Overestimates

Question 14

If GFR is low then serum creatinine _____

Answer 14

Increases

Question 15

Baby GFR…

Answer 15

20ml/min

Question 16

Renal clearance equation

Answer 16

Cx = Ux x V / Pax (arterial plasma)

Question 17

Creatinine clearance is used clinically for…

Answer 17

Pregnant women

Question 18

Ideal high creatinine person…

Answer 18

Black, bodybuilder, loves meat, on trimethoprim, eating creatine supplements

Question 19

Ideal low creatinine person….

Answer 19

Old, low muscle mass, female, hispanic/indo-asian, vegetarian

Question 20

True GFR can be measured with

Answer 20

Inulin

Question 21

You can have some decline in kidney function but no change in GFR…how is this possible?

Answer 21

Compensatory hypertrophy

Question 22

Little old lady will have lower serum creatinine- why is this a problem?

Answer 22

eGFR equations use serum creatinine levels so GFR will appear lower