Chapter 10 Acute Kidney Injury/ICU Nephrology

Question 1

What is the significance of acute kidney injury?

Answer 1

1. Increased mortality.
2. Increased risk of de novo chronic kidney disease.
3. Increased risk of accelerated chronic kidney disease progression.
   * Even in AKI that does not require dialysis.

Question 2

What is the KDIGO definition of AKI?

Answer 2

1. Increase in serum creatinine by 0.3 mg/dL within 48 hours or increase in serum creatinine by > 1.5 times baseline within prior 7 days.
2. Urine volume < 0.5ml/kg/hr for >/= 6 hours.

Question 3

What features would an ideal biomarker for AKI have?

Answer 3

1. The biomarker (in blood or urine) is increased within minutes to hours of the renal insult.
2. The biomarker remains elevated as long as the injury is present.
3. The biomarker elevation is proportional to the extent of injury.
4. The biomarker decreases with renal recovery.

Question 4

Name biomarkers used for the early detection of AKI.

Answer 4

1. KIM-1
2. NGAL
3. TIMP-2
4. IGF-binding protein 7 (IGFBP7).

Question 5

When are hyaline casts found?

Answer 5

Hyaline casts are found when there is reduced renal perfusion:

1. Volume depletion
2. Hypotension
3. Acute cardiopulmonary event
4. Drug-induced reduction in glomerular filtration
5. Abdominal compartment syndrome

Question 6

When are red blood cell casts found?

Answer 6

Red blood cell casts are found in acute glomerulonephritis.

Red blood cell casts can also be found in acute tubulointerstitial nephritis.

Question 7

When are white blood cell casts found?

Answer 7

White blood cell casts are found in pyelonephritis or tubulointerstitial nephritis.

Question 8

When are granular casts found?

Answer 8

Granular casts are non-specific.

Question 9

When are muddy brown casts found?

Answer 9

Muddy brown casts are found in acute tubular necrosis.

Question 10

When are waxy casts found?

Answer 10

Waxy casts are found in CKD with poor urine flow.

Question 11

When does anuria occur?

Answer 11

Anuria occurs in:

• Complete urinary obstruction
• Vascular catastrophe
• Severe acute tubular necrosis
• Severe rapidly progressive glomerulonephritis