20-4 (Acute Tubular Injury)

Question 1

ATI

Answer 1

Acute Tubular Injury

Question 2

What characterizes ATI?

Answer 2

Acute renal failure + tubular cell necrosis

Question 3

What are 2 causes of ATI?

Answer 3

1. Ischemia due to decreased blood flow

2. Toxins (endogenous/exogenous)

Question 4

What is the most common cause of an acute kidney injury?

Answer 4

ATI

acute tubular injury

Question 5

Why is it important to recognize ATI soon?

Answer 5

It is reversible if caught

Question 6

The pathogenesis of ATI involves 2 steps. What are they?

Answer 6

1. Tubular cell injury

2. Persistent and severe disturbances in blood flow

Question 7

The pathogenesis of ATI involves 2 steps. What are they?

Answer 7

1. Tubular cell injury

2. Persistent and severe disturbances in blood flow

Question 8

What factors predispose tubular cells to injury?

Answer 8

• Increased surface area and active transport system
• High rate of metabolism and O2 consumption
• Capable of resorbing toxins

Question 9

If ATI is caused by ischemia, how does that result in tubular cell injury?

Answer 9

Ischemia –> vasoconstriction –> injury

Question 10

With ATI, what portion of the nephron is usually injured?

Answer 10

Proximal tubule

Question 11

With ATI, what is the main 2 things seen on morphology?

Answer 11

• Necrosis

- Occlusion of the tubular lumen by casts

Question 12

With ATI, what is the 2 main things seen on morphology?

Answer 12

• Necrosis

- Occlusion of tubular lumen by casts

Question 13

If ischemia due to decreased blood flow causes ATI, what will the necrosis look like in the tubules?

Answer 13

Patchy in the PCT and PST

Question 14

Patchy necrosis in the PCT and PST indicates that ____ caused the ATI

Answer 14

Ischemia

Question 15

If toxins cause ATI, how will the necrosis look in the tubules?

Answer 15

Continuous necrosis in the PCT and PST

Question 16

Continuous necrosis in the PCT and PST indicates that _____ caused the ATI

Answer 16

Toxins

Question 17

With ATI from either cause, casts will occlude the tubular lumen in the DCT and CD. Although, if due to ischemia, there will be more casts where?

Answer 17

Ascending loop of henle

Question 18

What are the 3 stages of ATI clinical manifestations?

Answer 18

1. Initiation phase
2. Maintenance phase
3. Recovery phase

Question 19

Initiation phase of ATI

Answer 19

Inciting event + slight decrease in urine output and slight increase in BUN/Cr

Question 20

Maintenance phase of ATI

Answer 20

Oliguric crisis and uremia

Question 21

Recovery phase of ATI

Answer 21

Increased urine output + hypokalemia

Question 22

Inciting event + slight decrease in urine output and slight increase in BUN

Answer 22

Initiation phase of ATI

Question 23

Oliguric crisis + uremia

Answer 23

Maintenance phase of ATI

Question 24

Increased urine output + hypokalemia

Answer 24

Recovery phase of ATI

Question 25

What does recovery from ATI depend on?

Answer 25

Magnitude and duration of injury and involvement of other organs

Question 26

Most casts that are occluding the tubular lumen in the ascending loop of henle suggest that the ATI was caused by?

Answer 26

Ischemia due to decreased blood flow

Question 27

What are the 2 common causes of ATI and what are the 2 steps in the pathogenesis?

Answer 27

Causes:
1. Ischemia
2. Toxins
Pathogenesis:
1. Tubular cell injury
2. Persistent and severe disturbances in blood flow