1 Acute Kidney Injury, part 1

Question 1

Remarks on Acute Kidney Injury

Answer 1

For most causes of AKI, global or regional decrease in renal blood flow is the final common pathway. Recovery from AKI first depends on restoration of renal blood flow.

Question 2

The most common cause of intrinsic AKI

Answer 2

ischemic injury or ischemic tubular necrosis (also historically called acute tubular nacrosis), when renal perfusion is decreased so much that the kidney parenchyma is affected.

Question 3

This is virtually pathognomonic of obstruction

Answer 3

alternating oliguria and polyuria

Question 4

Stage 1 AKI

Answer 4

Serum Crea ↑ 1.5x
or
Crea ↑ >0.3 mg/dL over <48 hours
or
GFR ↓ 25-50%
or
Urine output 0.5 mL/kg/h for 6 hours

Question 5

Stage 2 AKI

Answer 5

Serum crea ↑ 2.0 - 3.0x
or
GFR ↓ 50-75%
or
0.5 mL/kg/h for 12 hours

Question 6

Stage 3 AKI

Answer 6

Serum Crea ↑ >3.0x
or
Serum Crea >4 mg/dL (≥354 umol/L)
and acute ↑ >0.5 mg/dL (44 umol/L)
or
GFR ↓ >75%
or
0.3 mL/kg/h for 24 h
or
Anuria for 12 hours

Question 7

Acute Kidney Loss

Answer 7

Complete loss of kidney function for >4 weeks

Question 8

End-stage renal disease

Answer 8

Need for renal replacement therapy for >3 months

Question 9

For AKI in the ED, the goals are

Answer 9

1. Identify patients at risk for AKI
2. Correct metabolic effects
3. Decrease ongoing renal injury
4. Prevent iatrogenic injury

Question 10

Fastest screening test for hyperkalemia

Answer 10

ECG
But sensitivity for a level over 6.5 mmol/L is 14-60%
Peaked T waves are only seen in 34% of patients

Question 11

This suggests bladder outlet obstruction

Answer 11

A large postvoid bladder residual volume (>125 mL)

Question 12

Anuria is defined as

Answer 12

<100 mL of urine per day, and can be present with prerenal, postrenal, or intrinsic

Question 13

Remarks on prerenal AKI

Answer 13

Prerenal AKI is also a common precursor to ischemic and nephrotoxic conditions, leading to intrinsic AKI

Question 14

The most common cause of postrenal AKI

Answer 14

prostatic hypertrophy

Question 15

most common cause of AKI in hospitalized patients

Answer 15

intrinsic kidney injury
Hospital AKI si due to toxic and ischemic insults in most cases.

Question 16

Contrast-induced nephropathy is defined by

Answer 16

a relatively small change in serum creatinine (25% increase from baseline or an absolute increase of 0.5 mg/dL [44 umol/L] 48 to 72 hours after infusion)

Question 17

Remarks on contrast-induced nephropathy

Answer 17

Studies found no differences in mortality, development of chronic kidney disease, or need for dialysis or renal transplantation in the future between contrast-exposed patients and unexposed patients.

Prevention of worsening renal function due to contrast exposure continues to serve as an indication for hydration prior to contrast-enhanced imaging for patients with preexisting chronic kidney disease

Question 18

Most common causes of crystal-induced AKI

Answer 18

Elevated uric acid levels in the setting of tumor lysis syndrome
and some medications - in particular, acyclovir, sulfonamides, indinavir, and triamterene

Question 19

Remarks on ACE inhibitors and NSAIDS

Answer 19

ACEi cause a preferential efferent arteriolar vasodilation in the renal glomerulus

NSAIDS cause afferent renal arteriole vasoconstriction (decreasing both GFR and renal blood flow)

Question 20

This drug class may cause rhabdomyolysis

Answer 20

Statins

Question 21

The most common antiviral implicated in AKI

Answer 21

antiretrovirals
acyclovir
valacyclovir

Question 22

Nephrotic syndrome

Answer 22

Proteinuria
Hypoalbuminemia
Edema
Hyperlipidemia

Question 23

Nephritic syndrome

Answer 23

Hematuria, RBC casts
Oliguria
Hypertension