Acute Kidney Injury

Question 1

What are the three type of Acute Kidney Injury and which is most common?

Answer 1

Pre-renal (Most Common)
Renal
Post-renal

Question 2

What is the basic etiology of pre-renal failure?

Answer 2

Lack of blood flow to the kidney (decreased renal perfusion)

Question 3

What finding is ALWAYS present in pre-renal failure?

Answer 3

Oliguria

Question 4

What is the classic BUN:Cr ratio seen in pre-renal failure? Why?

Answer 4

> 20:1

Kidney’s ability to reabsorb urea is preserved

Question 5

What is the urine osmolality in pre-renal failure? Why?

Answer 5

Increased, >500 mOsm/Kg

Kidney is still able to reabsorb H2O

Question 6

What is the urine Na+ in pre-renal failure? What is the FENa+? Why?

Answer 6

Decreased
<1%
Na+ is avidly reabsorbed in an attempt to maintain blood volume and renal perfusion

Question 7

How is urine:plasma creatinine ratio affected in pre-renal failure? Why?

Answer 7

Increased (>40:1)

Much of the filtrate is reabsorbed but not creatinine

Question 8

What are the four major groups of intrinsic renal failure?

Answer 8

Glomerular disease
Tubular disease
Vascular disease
Interstitial disease

Question 9

What is the basic pathophysiology in intrinsic renal failure? What is dysfunctional?

Answer 9

Glomerular and tubular function are impaired

Question 10

How is BUN:Cr affected in intrinsic renal failure

Answer 10

Less than pre-renal failure (<20:1), typically closer to 10:1

Question 11

How is urine Na+ level affected in intrinsic renal failure? What is the FENa+?

Answer 11

Increases

>2%

Question 12

How is urine osmolality affected in intrinsic renal failure? Why?

Answer 12

Decreased

Kidney’s ability to reabsorb water is decreased, so water is lost in the urine

Question 13

How is urine[Cr]:plasma[Cr] affected in intrinsic renal failure? Why?

Answer 13

Decreased (<20:1)

Inability to reabsorb filtrate

Question 14

What are the two major types of Acute Tubular Necrosis?

Answer 14

Ischemic

Nephrotoxic

Question 15

What are the phases of Acute Tubular Necrosis?

Answer 15

Oliguric
Diuretic
Recovery

Question 16

What are two blood findings during oliguric phase of ATN?

Answer 16

Azotemia

Uremia

Question 17

How long does the oliguric phase of ATN last?

Answer 17

10-15 days

Question 18

What is the urine output during the oliguric phase?

Answer 18

<500mL/day

Question 19

The diuretic phase of ATN begins when the urine output is what?

Answer 19

> 500mL

Question 20

What are the three factors that cause increased urine output during the diuretic phase of ATN?

Answer 20

1) Fluid overload - Excretion of retained salt, water, and other solutes from the oliguric phase
2) Osmotic diuresis: Excretion of retained solutes during oliguric phase
3) Tubular Cell Damage: Epithelial cell function recovers slower relative to GFR

Question 21

What six test should be done for any patient with AKI?

Answer 21

1. Urinalysis
2. Urine chemistry
3. Serum electrolytes
4. CBC
5. Bladder cateterization
6. Renal ultrasound

Question 22

What are the two most common deadly complications of AKI?

Answer 22

Pulmonary edema

Hyperkalemic cardiac arrest