20-4 (Acute Tubular Injury) Flashcards
ATI
Acute Tubular Injury
What characterizes ATI?
Acute renal failure + tubular cell necrosis
What are 2 causes of ATI?
- Ischemia due to decreased blood flow
2. Toxins (endogenous/exogenous)
What is the most common cause of an acute kidney injury?
ATI
acute tubular injury
Why is it important to recognize ATI soon?
It is reversible if caught
The pathogenesis of ATI involves 2 steps. What are they?
- Tubular cell injury
2. Persistent and severe disturbances in blood flow
The pathogenesis of ATI involves 2 steps. What are they?
- Tubular cell injury
2. Persistent and severe disturbances in blood flow
What factors predispose tubular cells to injury?
- Increased surface area and active transport system
- High rate of metabolism and O2 consumption
- Capable of resorbing toxins
If ATI is caused by ischemia, how does that result in tubular cell injury?
Ischemia –> vasoconstriction –> injury
With ATI, what portion of the nephron is usually injured?
Proximal tubule
With ATI, what is the main 2 things seen on morphology?
- Necrosis
- Occlusion of the tubular lumen by casts
With ATI, what is the 2 main things seen on morphology?
- Necrosis
- Occlusion of tubular lumen by casts
If ischemia due to decreased blood flow causes ATI, what will the necrosis look like in the tubules?
Patchy in the PCT and PST
Patchy necrosis in the PCT and PST indicates that ____ caused the ATI
Ischemia
If toxins cause ATI, how will the necrosis look in the tubules?
Continuous necrosis in the PCT and PST
Continuous necrosis in the PCT and PST indicates that _____ caused the ATI
Toxins
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?
Ascending loop of henle
What are the 3 stages of ATI clinical manifestations?
- Initiation phase
- Maintenance phase
- Recovery phase
Initiation phase of ATI
Inciting event + slight decrease in urine output and slight increase in BUN/Cr
Maintenance phase of ATI
Oliguric crisis and uremia
Recovery phase of ATI
Increased urine output + hypokalemia
Inciting event + slight decrease in urine output and slight increase in BUN
Initiation phase of ATI
Oliguric crisis + uremia
Maintenance phase of ATI
Increased urine output + hypokalemia
Recovery phase of ATI
What does recovery from ATI depend on?
Magnitude and duration of injury and involvement of other organs
Most casts that are occluding the tubular lumen in the ascending loop of henle suggest that the ATI was caused by?
Ischemia due to decreased blood flow
What are the 2 common causes of ATI and what are the 2 steps in the pathogenesis?
Causes: 1. Ischemia 2. Toxins Pathogenesis: 1. Tubular cell injury 2. Persistent and severe disturbances in blood flow
