Introduction to Acute Kidney Injury

Question 1

Definition of acute kidney injury

Answer 1

Rapid reduction of GFR manifested by a rise in plasma creatinine, urea, and other waste products.

Question 2

Definition of pre-renal azotemia

Answer 2

Decrease in GFR due to a decrease in renal plasma flow and/or renal perfusion pressure

Question 3

Definition of post-renal azotemia or obstructive nephropathy

Answer 3

Decrease in GFR due to obstruction of urine flow

Question 4

Definition of intrinsic renal disease

Answer 4

Decrease in GFR due to direct injury to the kidneys. May be due to a variety of insults.

Question 5

Definition of oliguria

Answer 5

24hr urine volume

Question 6

Definition of anuria

Answer 6

24hr urine volume

Question 7

What is the most common cause for abrupt fall in GFR in a hospitalized patient?

Answer 7

Pre-renal azotemia is the most common cause of an abrupt fall in GFR in a hospitalized patient

Question 8

T/F: Pre-renal azotemia is only associated with hypovolemia.

Answer 8

F. Congestive heart failure, for example, is one of many hypervolemic states that can lead to pre-renal azotemia

Question 9

Name two conditions that can lead to a low effective arterial blood volume (EABV)

Answer 9

Congestive heart failure and cirrhosis.

Question 10

How do the renal tubules function in pre-renal azotemia?

Answer 10

Normally

Question 11

In pre-renal azotemia, urine creatinine is _____

Answer 11

High

Question 12

In pre-renal azotemia, urine sodium is _____

Answer 12

Low

Question 13

T/F: A unilateral obstruction in Jason’s left kidney could lead to postrenal azotemia.

Answer 13

F. In normal persons, a bilateral obstruction is necessary to drastically decrease GFR.

Question 14

What is the most sensitive test for the diagnosis of renal obstruction leading to postrenal azotemia?

Answer 14

Ultrasound. Although those bastards in the ER would probably order a CT as well.

Question 15

What are the four types of intrinsic renal disease that lead to AKI?

Answer 15

1. Vascular
2. Glomerular
3. Interstitial
4. Tubular
   These are the 4 parts of the kidney. Vessels, glomeruli, tubes, interstitial.

Question 16

What causes acute tubular necrosis (ATN)?

Answer 16

Ischemia or nephrotoxins (usually medications)

Question 17

T/F: Finding hyaline casts in Ned’s urine would be a pathologic finding

Answer 17

F. Hyaline casts are acellular and are normal findings in healthy individuals

Question 18

What are RBC casts associated with?

Answer 18

Glomerulonephritis

Question 19

What are WBC casts associated with?

Answer 19

AIN (allergic interstitial nephritis)

Question 20

In general, what does a low FENa suggest?

Answer 20

A low FENa suggests prerenal azotemia

Question 21

With what is a high FENa associated?

Answer 21

A high FENa is associated with AKI associated from NON-prerenal causes.

Question 22

How do you treat post-renal azotemia?

Answer 22

Clear the obstruction

Question 23

How do you treat ATN?

Answer 23

Try to avoid it in the first place. If that doesn’t happen dialysis and convert from oliguric using loop diuretics.