Intro to Acute Renal Failure and Clearance

Question 1

What is inulin?

Answer 1

A polymer of fructose

Question 2

Creatinine is made by the _________ and stored in the __________.

Answer 2

kidneys and liver; muscles

Question 3

________ percent of creatinine is secreted.

Answer 3

Fifteen

Question 4

Creatinine is a breakdown product of _____________.

Answer 4

muscle metabolism

Question 5

Creatinine clearance is determined by this equation: ____________.

Answer 5

GFR x plasma creatinine levels

Question 6

What is SNGFR?

Answer 6

Single nephron glomerular filtration rate

Question 7

SNGFR is proportional to __________.

Answer 7

pressure in the glomerular capsule

Question 8

What does the renal blood flow do in response to acute hypovolemia?

Answer 8

The afferent arteriole dilates and the efferent arteriole constricts.

Question 9

What are three sources of azotemia?

Answer 9

Pre-renal (cardiac)
Intrarenal
Post-renal (obstructive, commonly ureteral or urethral)

Question 10

__________ are pathognomonic for glomerular injury.

Answer 10

Red blood cell casts

Question 11

With pre-renal tubular injury, sodium will be ________.

Answer 11

low

Question 12

Pre-renal AKIs don’t have to result from hypovolemic states. Some can even be __________.

Answer 12

hypervolemic, such as CHF

Question 13

Give the formula for FENa.

Answer 13

FENa = ([urine sodium] / [plasma sodium]) / ([urine creatinine] / [serum creatinine]) x 100

Question 14

List the types of intrinsic renal injury and some causes of each.

Answer 14

Vascular: renal vein thrombosis, cholesterol emboli
Glomerular: hemolytic uremic syndrome, glomerulonephritis
Interstitial: infection, myeloma kidney, and allergic interstitial nephritis
Tubular: ischemic kidney, nephrotoxic injury

Question 15

What is Tamm-Horsfall?

Answer 15

A mucoprotein that lines the tubule

Question 16

Casts are _____________.

Answer 16

mucoproteins primarily found on the distal tubule that congeal onto tubular epithelial cells; will catch anything flowing in the tubule, such as RBCs or WBCs

Question 17

_________ azotemia will have high specific gravity.

Answer 17

Prerenal (vasculitis and glomerulonephritis can also have high SGs, but they are often isotonic)

Question 18

Granular casts are indicative of __________.

Answer 18

tubular injury

Question 19

What is the formula for clearance?

Answer 19

Cl = ([urine concentration] x [urine production]) / (plasma concentration)

Question 20

What is the formula for estimating creatinine clearance?

Answer 20

[(A) x (140 - age) x weight]/ (72 x SCr)
Where A is 1 for men and 0.85 for women
Weight is in kilograms
Scr is in mg/dl