Lecture 22

Question 1

What are the characteristics of focal segmental glomerulosclerosis (FSGS)?

Answer 1

-most common cause of non-ICGN
-less than 50% of glomeruli have sclerosis in less than 50% of their tuft
-due to podocyte injury

Question 2

What are the characteristics of primary FSGS?

Answer 2

-assumed to be due to abnormal podocyte genes/proteins
-seen in soft-coated wheaten terriers

Question 3

What are the potential causes of secondary FSGS?

Answer 3

-systemic hypertension
-obesity
-decreased nephron mass/increased single nephron GFR
-podocytotoxic drugs

Question 4

How does glomerulonephritis differ from glomerulitis?

Answer 4

*glomerulonephritis:
-immune-mediated lesion

*glomerulitis:
-inflammation restricted to glomeruli

Question 5

What are the characteristics of embolic nephritis?

Answer 5

-caused by bacteria or viruses
-bacteremia is most common cause
-hematogenous route of infection
-spectrum of glomerulitis leads to multifocal interstitial nephritis
-initially a suppurative inflammation
-gross appearance of petechial hemorrhages and abscesses smaller than 1 mm
-always multifocal, almost always bilateral, and predominantly cortical

Question 6

What is the gross appearance of acute tubulointerstitial disease?

Answer 6

-may look normal
-paler than normal
-swollen
-red foci from hemorrhages
-bulges on cut section
-streaking in parenchyma

Question 7

What is the gross appearance of chronic tubulointerstitial disease?

Answer 7

-lumpy bumpy
-pits and depressions on cortical surface
-smaller than normal
-firm and pale tan to white-tan

Question 8

What are the characteristics of granulomatous nephritis?

Answer 8

-mass lesions
-often involves other organs
-can be difficult to distinguish from neoplasia

Question 9

What are the potential causes of granulomatous nephritis?

Answer 9

-systemic fungi
-parasite migration; Toxocara
-Mycobacterium bovis
-FIP

Question 10

What are the gross findings in FIP?

Answer 10

-multifocal to coalescing, soft to firm, white-tan nodules
-lesions often focused around vessels/vasculitis

Question 11

What are the differential diagnoses for the gross white-tan nodular appearance seen in FIP?

Answer 11

-neoplasia or nodular hyperplasia
-abscess
-granuloma

Question 12

What are the characteristics of acute tubular injury?

Answer 12

-acute tubular necrosis
-most important lesion underlying acute kidney injury
-main clinical signs are oliguria/anuria
-renal tubular epithelium is metabolically active and highly susceptible to injury

Question 13

What are the most common acute tubular injury causes?

Answer 13

-nephrotoxins
-pigmentary nephropathy
-tubular ischemia
-obstruction

Question 14

What is the gross appearance of acute tubular injury?

Answer 14

-often looks normal
-swollen
-bulges on cut section
-pale streaks or diffusely pale tan to beige

Question 15

What are the characteristics of ethylene glycol toxicity?

Answer 15

-most common in cats, then dogs, then other species
-rapidly absorbed from GI tract
-metabolized in liver into metabolites that are nephrotoxic

Question 16

What are other potential causes of oxalate crystals other than ethylene glycol?

Answer 16

-high dietary oxalates
-high amounts of ascorbic acid
-chronic pancreatitis

Question 17

What are the determinants for recovery in acute tubular injury cases?

Answer 17

-timely removal of cause
-maintenance of tubular basement membranes
-cytokine expression in tubular epithelial cells

Question 18

What are the characteristics of hemoglobinuria?

Answer 18

-consequence of severe intravascular hemolysis
-large quantities of hemoglobin in urinary filtrate make epithelium more prone to ischemic injury + toxic to tubules
-gross appearance is dark red-black kidneys and red urine

Question 19

What are possible causes of hemoglobinuria?

Answer 19

-lepto
-bacillary hemoglobinuria
-babesiosis
-chronic copper poisoning
-red maple toxicity

Question 20

What are the characteristics of myoglobinuria?

Answer 20

-occurs when high levels of myoglobin are filtered into the tubules and lead to acute tubular injury
-gross appearance is dark red to black kidneys and dark red urine
-grossly and histologically similar to hemoglobinuria

Question 21

What are potential causes of myoglobinuria?

Answer 21

-capture myopathy in wild animals
-equine exertional rhabdomyolysis
-severe direct trauma to muscle

Question 22

What are the potential causes of ischemic acute tubular injury?

Answer 22

-hypovolemic shock
-neurogenic shock
-cardiogenic shock
-septic shock
-DIC

Question 23

What are the characteristics of papillary necrosis?

Answer 23

-ischemic necrosis of renal medulla
-due to decreased blood flow in vasa recta
-gross appearance is a darkened, recessed medullary crest or renal papilla

Question 24

What are potential causes of papillary necrosis?

Answer 24

-NSAID toxicity
-pyelonephritis
-urinary obstruction
-interstitial renal amyloidosis
-exacerbated by dehydration with any cause

Question 25

What is the acute gross appearance of tubulo-interstitial nephritis?

Answer 25

-may look normal -pale areas within cortex or diffuse pallor

Question 26

What is the chronic gross appearance of tubulo-interstitial nephritis?

Answer 26

-kidneys shrunken and firm -streaks of fibrosis -capsule adhered -finely pitted cortical surface

Question 27

What are the potential causes of tubulo-interstitial nephritis?

Answer 27

-lepto -canine lyme disease -often unknown cause

Question 28

What are the characteristics of pyelonephritis?

Answer 28

-inflammation of renal pelvis and parenchyma -can be acute or chronic -seen in pigs, cattle, and dogs most often -due to ascending bacterial infection -can cause papillary necrosis, leading to decreased concentrating ability

Question 29

What are the predisposing factors for pyelonephritis?

Answer 29

-urinary obstruction -vesico-ureteral reflux -cystitis -age -urogenital anatomy

Question 30

What is the general gross appearance of pyelonephritis?

Answer 30

-changes of inflammation in pelvis that extend into parenchyma; most severe at poles -concurrent cystitis and/or ureteritis

Question 31

What is the acute gross appearance of pyelonephritis?

Answer 31

-enlarged kidneys -suppurative exudate in pelvis -partial destruction of medulla -patchy or streaky pallor of cortex

Question 32

What is the chronic gross appearance of pyelonephritis?

Answer 32

-shrunken, misshapen kidneys -streaks of fibrosis through cortex and medulla

Question 33

What are the characteristics of hydronephrosis?

Answer 33

-dilation of renal pelvis and calyces with progressive atrophy of renal parenchyma -caused by obstruction -commonly associated with hydroureter

Question 34

What are the characteristics of "end stage kidney disease"?

Answer 34

-used to describe kidneys severely affected by chronic inflammation and fibrosis -often associated with a clinical diagnosis of CKD -not possible to identify primary insult

Question 35

What are the characteristics of Dioctiophyma renale?

Answer 35

-giant kidney worm -seen in mink, dog, and other fish-eating mammals -large nematode that resides in renal pelvis -can also be found in peritoneal cavity

Question 36

What are the characteristics of renal hemorrhages?

Answer 36

-petechial or ecchymotic -common result of vasculitis -easily overlooked if renal capsule is not removed -glomeruli preferentially affected

Question 37

What are the potential causes of renal hemorrhage?

Answer 37

-bacteremia -viremia -toxins -coagulopathies

Question 38

What are the characteristics of renal infarcts?

Answer 38

-associated with thrombosis of renal vessels -usually interlobular -common site for infarcts due to high circulating blood volume

Question 39

What is the gross appearance of renal infarcts?

Answer 39

*well-demarcated, triangular shape with apex pointing towards medulla *acute: -red to pale -soft -slightly swollen -hyperemic rim *chronic: -pale -firm -depressed surface