Acute Kidney Injury 3

Question 1

What are the main causes of prerenal AKI?

Answer 1

Hypovolemia, hypervolemia with decreased effective circulating volume, and hypotension.

Question 2

What are examples of hypovolemic causes of prerenal AKI?

Answer 2

Hemorrhage, GI losses (vomiting, diarrhea), urinary or cutaneous losses.

Question 3

What conditions cause hypervolemia with decreased effective circulating volume in prerenal AKI?

Answer 3

Nephrotic syndrome, cardiac dysfunction, and liver disease.

Question 4

What types of shock can lead to prerenal AKI?

Answer 4

Septic and myocardial shock.

Question 5

How does the body respond to decreased renal perfusion?

Answer 5

Increased sympathetic tone, and hormonal responses such as renin, angiotensin II, aldosterone, and ADH release.

Question 6

What role do prostaglandins play in prerenal AKI?

Answer 6

They cause afferent arteriole dilation to maintain GFR.

Question 7

How does angiotensin II affect renal arterioles?

Answer 7

It constricts efferent arterioles to preserve GFR.

Question 8

Is the renal structure intact in prerenal AKI?

Answer 8

Yes, the glomeruli, interstitium, and tubular structures remain intact.

Question 9

What happens if hypoperfusion persists in prerenal AKI?

Answer 9

It may progress to intrinsic AKI.

Question 10

What are key historical features of prerenal AKI?

Answer 10

Hemorrhage, vomiting, diarrhea, fever, weight loss, and decreased urine output.

Question 11

What physical signs indicate dehydration or hypoperfusion in prerenal AKI?

Answer 11

Tachycardia, hypotension, poor skin turgor, dry mucous membranes, sunken eyes/fontanelle, and prolonged capillary refill (>2 seconds).

Question 12

What physical finding suggests nephrotic syndrome, cardiac dysfunction, or liver disease in prerenal AKI?

Answer 12

Edema.

Question 13

What BUN-to-creatinine ratio suggests prerenal AKI?

Answer 13

Greater than 20.

Question 14

What is the typical urine specific gravity in prerenal AKI?

Answer 14

Greater than 1.020.

Question 15

What is the typical urine osmolality in prerenal AKI?

Answer 15

Greater than 500 mOsm/kg.

Question 16

What is the normal urine sodium level in children with prerenal AKI?

Answer 16

Less than 10 mEq/L.

Question 17

What is the normal urine sodium level in neonates with prerenal AKI?

Answer 17

Less than 20–30 mEq/L.

Question 18

What is the fractional excretion of sodium (FENa) in children with prerenal AKI?

Answer 18

Less than 1%.

Question 19

What is the FENa threshold in neonates with prerenal AKI?

Answer 19

Less than 3%.

Question 20

How is prerenal AKI diagnosis confirmed?

Answer 20

Return of serum creatinine to baseline after volume repletion.

Question 21

What are the core principles of managing prerenal AKI?

Answer 21

Address the underlying cause, provide volume resuscitation, and maintain adequate renal perfusion.

Question 22

How does fluid management help in prerenal AKI?

Answer 22

It restores renal perfusion and prevents progression to intrinsic AKI.

Question 23

What are clinical clues for diagnosing prerenal AKI?

Answer 23

Dehydration signs such as capillary refill >2 seconds, tachycardia, and sunken eyes.

Question 24

Why is prerenal AKI considered functional?

Answer 24

It results from decreased perfusion without structural kidney damage.

Question 25

What are common but non-specific findings in prerenal AKI urinalysis?

Answer 25

Hyaline casts.