Renal Pathology

Front 1

What are the 3 R's of the renal system?

Back 1

redundancy: 2 kidneys

reserve: only need 1/4 - 1/3 of total renal mass to survive

regeneration: tubules (great) vs. glomerulus (none)

Front 2

What is the most common sign of glomerular dysfunction?

Back 2

proteinuria

Front 3

What are the primary functions of the kidney?

Back 3

excrete nitrogenous & other metabolic wastes: BUN, creatinine, ammonia, P, K

conserve body water, electrolytes (Na, Cl, Ca), AAs, proteins, glucose

regulate pH: conserve HCO3-, excrete H+, NH3+

Front 4

ADH

a. located of receptors
b. effect
c. where produced

Back 4

a. collecting tubules
b. reabsorption of H2O
c. produced by hypothalamus, stored in pituitary

Front 5

PTH

a. located of receptors
b. effect
c. where produced

Back 5

a. tubules responsible for Ca-P homeostasis
b. reabsorption of Ca, excretion of P
c. parathyroid glands

Front 6

aldosterone

a. located of receptors
b. effect
c. where produced

Back 6

a. tubules
b. reabsorption of Na, excretion of K
c. adrenal glands

Front 7

What are the 4 disorders that make up the nephrotic syndrome?

Back 7

proteinuria, hypoproteinemia, edema, hypercholesterolemia

Front 8

What are some non-renal lesions that are associated w/ uremia?

Back 8

vasculitis: more characteristic of ACUTE uremia (lesions: petechiae, ecchymosis, GI hemorrhage, edema, ascites, necrosis of tip of tongue, oral ulcers)

edema: primarily in dog & cat

stomatitis
hemorrhagic, ulcerative lesions in GI tract
mineralization
parathyroid hyperplasia & hypertrophy: chronic
renal osteodystrophy (rubber jaw): chronic
pulmonary thrombosis
anemia: mild to moderate nonregenerative (chronic)

Front 9

familial progressive renal dystrophy

a. signalment
b. lesions

Back 9

a. dogs (Lhasa Apso, Shih Tzu, Cockers, Norwegian Elkhounds, Dobermans, Samoyeds, etc.); common
b.
-CRF, chronic lesions, despite young age
-kidneys normal at birth
-kidneys undergo severe fibrosis & atrophy, often at a young age
-may be hypercalcemic (rather than usual hypocalcemia assoc. w/ renal failure)

Front 10

What is the pathogenesis of congenital renal cysts?

Back 10

failure of mesonephros (collecting part) to fuse w/ metanephros (secretory part) --> blind ended tubule that fills w/ fluid

may be simple or polycystic

Front 11

What is the pathogenesis of acquired renal cysts?

Back 11

some physical structure (ex. calculus, chronic inflammation, scar tissue) obstructs tubules --> tubules proximal to obstruction dilate & become cystic

Front 12

What are the gross lesions of hydronephrosis?

Back 12

hydroureter, symmetrical dilation of pelvis on cut surface, bilaterally symmetrical (if obstruction is distal enough)

can see calices & interstitium: shouldn’t be able to see

Front 13

What is the pathogenesis of ascites d/t glomerular dz?

Back 13

↑ permeability of filter --> protein leakage --> proteinuria --> hypoproteinemia --> ↓ colloidal osmotic pressure --> edema, ascites

Front 14

What are the 2 mechanisms of glomerulonephritis?

Back 14

immune mediated
embolic

Front 15

What is the pathogenesis of immune mediated glomerulonephritis?

Back 15

-immune complexes (ICs) in circulation trapped in walls of small caps in glomeruli, eyes, synovium
-ICs --> chemotaxis of WBCs & activation of inflammatory cascades
-Igs deposited (positively charged) --> BM thickens & becomes more permeable --> area loses net negative charge --> loss of filtering function
-net negative charge normally contributes large part to functional barrier of glomerulus to circulating anions like albumin
-Abs directed against these Ags form ICs: heartworm dz, FelV, pyometra, endocarditis, SLE, Ehrlichia canis, etc. (most cases: IDIOPATHIC)

-anti-GM: Abs against glomerular basement mem (rare)

Front 16

What is the pathogenesis of embolic glomerulonephritis?

Back 16

septicemia --> bacteria lodge in glomeruli & interstitial caps & expand to adj. parenchyma

-sources of sepsis: endocarditis, umbilicus (neonates: FPT), Actinobacillosis (foals)
-infection usually disseminated: joints, adrenals, lungs

Front 17

What are the gross lesions of embolic glomerulonephritis?

Back 17

early: red dots (hyperemia, hemorrhage in glomeruli)
later: white foci
late: multifocal abscesses

Front 18

What is the pathogenesis of renal amyloidosis?

Back 18

deposition of unique protein (AA) assoc. w/ chronic bacterial infections, hyperimmune conditions (pyelonephritis, osteomyelitis, foot abscess, pleuritis, pneumonia, neoplasia, etc.)

Front 19

What is the name of dz in the tubules?

Back 19

nephrosis

Front 20

What are the 2 types of nephrosis?

Back 20

toxic
ischemic

Front 21

What are some etiologies of toxic nephrosis?

Back 21

ethylene glycol, oakbud (cows), aminoglycosides, Phenylbutazone, Clostridium (pulpy kidney: sheep), endogenous, etc.

Front 22

What is the pathogenesis of ischemic nephrosis?

Back 22

↓ perfusion to lower nephron --> degeneration & necrosis of tubular epi: shock, severe DIC

Front 23

What is the pathogenesis of intravascular hemolysis --> ischemic necrosis?

Back 23

↓ O2 carrying capacity --> ↓ O2 to cells --> stimulation of renin release --> vasoconstriction --> further ↓ perfusion

Front 24

What is the one exception to the rule that interstitial nephritis is chronic?

Back 24

leptospirosis

Front 25

What are some etiologies assoc. w/ suppurative hematogenous interstitial nephritis?

Back 25

-endocarditis
-septicemia: Actinobacillosis in foals, white spotted kidney dz (E. coli) in cows, Erysipelothrix in pigs

Front 26

What are some etiologies of granulomatous interstitial nephritis?

Back 26

FIP
early stage of leptospirosis

Front 27

What is the pathogenesis of suppurative hematogenous interstitial nephritis?

Back 27

hematogenous spread of infection to kidney where bacterial emboli usually lodge in glomeruli & interstitial caps (usually an embolic suppurative GN along w/ interstitial suppurative inflammation)

Front 28

What are some causes of chronic interstitial nephritis?

Back 28

-idiopathic: most common
-Leptospirosis: see granulomatous interstitial dz
-K9 herpes virus: rare
-cats: most common renal dz assoc. w/ renal failure (develop hypokalemia)
-horses: any renal dz is uncommon, but CIN can occur & may be assoc. w/ hypercalcemia & hypophosphatemia

Front 29

What are 2 etiologies for renal petechiae?

Back 29

septicemia
K9 herpes: neonatal pups (< 10 d.): petechiae in & on kidneys & other organs (ex. lungs): petechiae essentially diagnostic

Front 30

What are the gross lesions of renal infarcts & why is infarction of kidney common?

Back 30

-focal or multifocal, often wedge shaped
-only so many nephrons function at a time (only those will be plugged w/ emboli)
-dehemoglobinization: removal of Hb causes color change from red to white

-common in kidney d/t little or no collateral circulation (rarely produces renal failure)

Front 31

What is renal cortical necrosis?

Back 31

-thrombosis in many glomerular caps --> sudden ischemic necrosis (multifocal or diffuse depending on # of nephrons involved)
-severe lesion, will kill patient unless you treat DIC & primary dz vigorously
-cause: DIC

Front 32

What are the 2 types of pyelonephritis?

Back 32

hematogenous (descending)
urogenous (ascending)

Front 33

What are some causes of hematogenous (descending) pyelonephritis?

Back 33

endocarditis, septicemia (newborns), Actinobacillosis (foals)

just an advanced stage of suppurative embolic glomerulointerstitial nephritis that now has extended into pelvis

Front 34

What is the pathogenesis of urogenous (ascending) pyelonephritis?

Back 34

infection ascends from lower urinary tract, penetrates pelvis --> necrosis --> extends into tubules, then interstitium

cystitis ascends via vesicoureteral reflux --> bacteria from bladder to pelvis

Front 35

What type of inflammation is mostly commonly associated w/ pyelonephritis & what 2 species are most commonly affected?

Back 35

suppurative

dogs, cows

Front 36

What are the gross lesions of pyelonephritis?

Back 36

-acute: small suppurative foci
-chronic: abscess: can be large & make kidneys huge; fibrosis w/ time
-cut surface: erosion, ulceration of pelvis, pus in pelvis
-progresses to multiple abscesses scattered thru out cortex & medulla
-can look like LSA, infarcts, or white spotted kidney dz on natural surface (cut surface is diagnostic)

Front 37

What are etiologies of papillary necrosis?

Back 37

= necrosis of papilla d/t ischemia

-pyelonephritis: most common cause (papillary necrosis insignificant compared to pyelonephritis)
-vascular: edema in kidney, amyloid in kidney (esp. in cats), diabetes mellitus
-chemicals: Bute, sulfonamides (↓ H2O intake required to produce lesions)
-obstruction: esp. d/t renal calculi

Front 38

What is the pathogenesis of central diabetes insipidus?

Back 38

structural lesion in pituitary --> ↓ ADH (ddx: idiopathic, tumor, abscess)

Front 39

What is the pathogenesis of nephrogenic diabetes insipidus?

Back 39

CRF --> cells that respond to ADH are gone OR cells present but something interferes w/ ADH (ex. steroids (Cushing’s), hypercalcemia, E. coli toxin (pyometra))

Front 40

What are some causes of end stage kidneys?

Back 40

chronic GN, chronic pyelonephritis, chronic interstitial nephritis
-less common: severe amyloidosis, renal calculi

Front 41

What are some causes of renal mineralization?

Back 41

renal failure, Vit. D toxicity, primary hyperparathyroidism, hypercalcemia of malignancy, Ca X P > 90, Cushing’s, dystrophic mineralization

Front 42

What is Fanconi syndrome & with what breed of dog is it associated?

Back 42

-tubular reabsorption defect (biochemical problem w/ no morphologic lesion)
-urine: ↑ glucose, protein, AAs, lipid, etc.

Basenjis (up to 30%)

Front 43

What are some predisposing factors for cystitis?

Back 43

-anatomic: short urethra in females w/ wide lumen favors ascending infection
-trauma: induced by calculi
-neurogenic: d/t loss of innervation (ex. dogs (IVDD), horses (Sorghum cystitis))
- lack of innervation --> bladder atony --> urine pooling/stasis
-bacteria: esp. urea splitting bacteria --> alkalotic urine
-concurrent infection
-chronic steroid administration: --> hypotonic urine, ↓ neutrophil function
-parasites

Front 44

What are some etiologies of acute hemorrhagic cystitis?

Back 44

trauma (catheter, calculi), blister beetles (horses)

cats: severe hemorrhage & necrosis makes bladder wall susceptible to rupture, esp. if calculus is blocking exit of urine

Front 45

What are common causes for uroabdomen in:

a. foals
b. cats
c. cows

Back 45

a. newborn male foals, may occur during parturition
b. feline urological syndrome: necrotic bladder wall prone to iatrogenic rupture
c. “water belly”, usually d/t calculus lodged at sigmoid flexure

Front 46

Where are uroliths likely to lodge in:

a. cattle
b. rams
c. cats

Back 46

a. sigmoid flexure
b. sigmoid flexure &/or urethral process
c. tip of penis

Front 47

What contributes to the formation of uroliths?

Back 47

need a nidus for rest of elements to precipitate on (ex. matrix of bacteria, fibrin, mucus, protein, dead cells, etc.)

other factors: ↓ H2O intake (KEY!!), diet, acid vs. alkaline pH, diseases, familial

Front 48

What conditions may result from urolithiasis?

Back 48

pyelitis, cystitis, obstruction, uroabdomen, hydronephrosis, papillary necrosis, PAIN

Front 49

What is feline urological syndrome?

Back 49

common: blocked male cats
crystals --> uroliths --> obstruction
death usually d/t hyperkalemia
etiology: unknown (↓ H2O intake important)

Front 50

What are some primary renal tumors?

Back 50

adenocarcinoma: most common PRIMARY renal tumor of dogs (uncommon)

also adenoma, embryonal nephroma, nephroblastoma

Front 51

What is the most common tumor of the kidneys, what does it look like grossly, and what are the ddx in cows & cats?

Back 51

LSA
-multiple white nodules in any species (fairly common in dogs, cats, cows)
-will always be in other tissues as well

-cow ddx: pyelonephritis, white spotted kidney dz, LSA, infarct

-cat ddx: FIP, LSA
-differentiate by histology/cytology, FIP (peritonitis, pleuritis, polyclonal gammopathy), LSA (big lymph nodes, thymus, BM leukemia)

Front 52

What are 2 common tumors of the urinary bladder?

Back 52

transitional cell carcinoma: most common; very malignant

squamous cell carcinoma
-cattle: brackfern (80% of bladder neoplasms are carcinoma)