Diseases of Tubules and Interstitium

Question 1

What is acute renal failure?

Answer 1

Acute rise in serum creatinine

Question 2

What are the three types of ARF?

Answer 2

Prerenal, intrarenal, postrenal

Question 3

What is prerenal ARF?

Answer 3

Reduced BF to the kidneys

Question 4

What is the more commonly used name for intrarenal ARF?

Answer 4

Acute kidney injury

Question 5

How is AKI characterized?

Answer 5

By portion of the kidney that is primarily injured (glomeruli, tubules, vessels, interstitium)

Question 6

What is postrenal ARF?

Answer 6

ARF caused by urinary tract obstruction

Question 7

What is the most common cause of AKI?

Answer 7

Ischemic acte tubular injury

Question 8

If ischemia is severe enough to cause histologic tubular epithial injury, what is the Dx?

Answer 8

Considered intrarenal ARF or ischemic AKI

Question 9

T or F: Most ischemic acute tubular injury has widespread tubular epithelial necrosis

Answer 9

FALSE

Question 10

What causes ischemic ATN acute tubular injury?

Answer 10

Reduced renal perfusion associated with hypotension

Question 11

What is the typical histologic finding in Ischemic ATN acute tubular injury?

Answer 11

Flattening (simplification) of tubular epithelium due to sloughing of apical cytoplasm into urine

Question 12

What is nephrotoxic ATN caused by?

Answer 12

Chemically induced injury to epithelial cells

Question 13

What are the two general processes leading ATN AKI?

Answer 13

Dcreased glomerular filtration and tubular epithelial dysfunction

Question 14

A patient with ischemic acute tubular injury is shown. Describe the typical findings.

Answer 14

Necrosis of tubular epithelial cells is evident.

Question 15

Toxic acute tubular necrosis is shown. How is this different than ischemic tubular necrosis?

Answer 15

Widespread necrosis of proximal tubular epithelial cells.

Question 16

What is the leading cause of acute renal failure?

Answer 16

ATN ischemia

Question 17

What is characteristic of ATN ischemia?

Answer 17

Rapidly rising serum creatinine and decreased urine output (oliguria)

Question 18

What are “dirty brown” granular casts a marker of?

Answer 18

Acute renal failure

Question 19

What is the fractional excretion of sodium in a patient with prerenal ischemic acute tubular injury?

Answer 19

< 1%

Question 20

What is the fractional extretion of sodium in a kidney with tubular damage?

Answer 20

> 2%

Question 21

What are signs of kidney recovery?

Answer 21

Increased urine output and fall in serum creatinine

Question 22

What area the urinalysis sediment findings in acute tubular injury?

Answer 22

Dirty brown casts and epithelial cells

Question 23

What are the urinarlysis sediment findings in acute glomerulonephritis?

Answer 23

Red blood cell casts and proteinuria

Question 24

What are the urinalysis sediment findings in acute tubulointerstitialnephritis?

Answer 24

WBC casts and pyuria

Question 25

What is pyelonephritis?

Answer 25

Bacterial infection of the kidney

Question 26

What type of bug typically causes UTIs and acute pyelonephritis?

Answer 26

Uropathogenic E. coli

Question 27

What is a major virulence factor for uropathogenic E. coli?

Answer 27

Pyelonephritis-associated pili gene

Question 28

Following micturition, why is a minimal volume of urine preferable?

Answer 28

New sterile urine from kidneys can easily dilute remaining bacteria and decrease the likelihood of bacterial infection

Question 29

What type of renal papilla is this? What is the risk of having such a papilla?

Answer 29

Compound papilla; The peripheral compound papillae allow easier access for bacteria to the collecting system

Question 30

What is a typical finding that supports Dx of pyelonephritis?

Answer 30

Leukocyte casts

Question 31

What causes chronic pyelonephritis?

Answer 31

Recurrent/persistent bac infections due to urinary tract obstruction/urine reflux

Question 32

What can chronic pyelonephritis lead to?

Answer 32

Atrophy and scarring of papillary tip and caliectasis (calyx dilation)

Question 33

What do only chronic pyelonephritis and analgesic nephropathy lead to?

Answer 33

Caliectasis and overlying corticomedullary scarring

Question 34

A patient with acute pyelonephritis is shown. What does the infiltrate primarily consist of?

Answer 34

Neutrophils are present w/I the collecting tubules and interstitial tissue

Question 35

A kidney with polar scars is shown. What caused this injury? Why were the poles injured? Vesiculoureteral reflux

Answer 35

Vesiculoureteral reflux resulting in chronic pyelonephritis; Poles injured because their papillae are the most susceptible (compound papillae)

Question 36

A kidney with papillary necrosis in all papillae is shown. What is the cause of severe papillary necrosis caused by high pressure backflow?

Answer 36

Obstruction of the urinary tract leading to chronic pyelonephritis and papillary necrosis

Question 37

What is Xanthogranulomatous pyelonephritis?

Answer 37

Uncommon pyelonephritis caused by Proteus, E. coli, Klebsiella and Pseudomonas

Question 38

What is the ultimate result of analgsic nephropathy?

Answer 38

Papillary necrosis

Question 39

Drug -induced acute tubulointerstitial nephritis is shown below. What type of reaction is it?

Answer 39

It is a type IV hypersensitivity rxn with T cell and eosinophil infiltrates

Question 40

What proteins are deposited in light-chain cast nephropathy?

Answer 40

AL Amyloid

Question 41

Light chain cast nephropathy is shown. What determines the three subtypes? What are the three subtypes?

Answer 41

Light chain structure; Light-chain cast nephropathy, AL amyloidosis, or light-chain deposition disease

Question 42

Urate nephropathy is shown below. What are some conditions that can lead to this renal disease?

Answer 42

Increased cell turnover leading to high blood levels of uric acid

Question 43

What is the diagnostic feature of chronic urate nephropathy?

Answer 43

Gouty tophus

Question 44

What two conditions can hypercalciuria cause?

Answer 44

Nephrocalcinosis and nephrolithiasis

Question 45

What is the term used to describe nephrocalcinosis caused by hypercalcemia?

Answer 45

Metastatic calcification

Question 46

What is the term used to describe nephrocalcinosis at sites of renal parenchymal injury?

Answer 46

Dystrophic calcification