Urinary Calculi

Question 1

Uroliths

Answer 1

Polycrystalline concentrations located within the urinary tract
- >90% weight is composed of inorganic/organic crystalloid, with remainder consisting of organic matrix

Question 2

Canine bladder uroliths are commonly _______

Answer 2

Struvite!

Question 3

Most common stone is seen in the _____

Answer 3

Bladder

Question 4

Most common bladder stones are seen in _____

Answer 4

Female dogs

Question 5

Most female bladder stones are ______

Answer 5

Struvite

Question 6

_____ stones are common in dogs that eat sand

Answer 6

Silica

Question 7

Most common stone in cats is ______

Answer 7

Oxalate

Question 8

Urolith matrix

Answer 8

• matrix substance A
• tamm-horsfall mucoprotein
• uromucoid
• albumin
• globulins

Question 9

Initiation phase

Answer 9

Formation of a crystal nidus (nucleation) in the presence of urine supersaturation with calculogenic crystalloids

Question 10

Growth phase

Answer 10

Continued circumferential crystal deposition around the crystal nidus

Question 11

Do stones form in the ureters/urethra?

Answer 11

NO

Question 12

Urolith formation is influenced by

Answer 12

• urine supersaturation
• organic matrix
• urine pH
• crystal transit time
• crystallisation inhibitors or promoters

Question 13

Which stones form in acidic urine?

Answer 13

Oxalate

Question 14

Which stones form in alkaline urine?

Answer 14

Struvite

Question 15

Citrate in urine is a stone _____

Answer 15

Inhibitor

Question 16

Urine analysis

Answer 16

Urine sediment, collect by cystocentesis!

• crystalluria
• bacteriuria
• pyruia

Question 17

Crystalluria

Answer 17

Presence of crystals in urine

• limited diagnostic meaning, some crystals are found in normal urine
• nature of crystalluria does not always reflect type of calculus!

Question 18

Struvite crystals

Answer 18

House roofs

Question 19

Calcium oxalate dihydrate crystals

Answer 19

Square envelopes

Question 20

Calcium oxalate monohydrate crystals

Answer 20

Double ended picket fences

• do not form stones!
• end point of ethelene glycol toxicity

Question 21

Urate crystals

Answer 21

Brown, spiky

• not normally seen in urine, except Dalmations
• usually sign of severe liver dysfunction
• not benign

Question 22

Cystine stones

Answer 22

6 sided

• hereditary, common in bulldogs
• not normal in other breeds
• prone to cystine stones

Question 23

Imaging techniques

Answer 23

• plain radiography
• contrast radiography
• ultrasonography

Question 24

_____ and _____ are the same density on radiographs

Answer 24

Bladder and urine

Question 25

Radiopacity of uroliths

Answer 25

From radiodense to radiolucent: | - phosphate --> oxalate --> cystine --> uric acid/urate

Question 26

Every stone shows up on _______

Answer 26

Ultrasound! | - may miss stones in the urethra

Question 27

A renal calculus is also known as a _____

Answer 27

Nephrolith

Question 28

Severe hydronephrosis

Answer 28

End stage kidney dz secondary to ureter obstruction due to a stone that did not pass

Question 29

Stone analysis

Answer 29

- chemical or physical | - surgery is often the only means of obtaining a stone for analysis

Question 30

With a mixed stone, you would treat based on the type of stone in the ______

Answer 30

Middle | - the nidus

Question 31

Which stones are dissolvable?

Answer 31

Struvite and urate

Question 32

Which stones are resistant to dissolution?

Answer 32

- oxalate - silica - cystine - calcium phosphate

Question 33

Non-surgical alternatives

Answer 33

- voiding urohydropropulsion - ureteral stents - lithotripsy: intracorporeal and exttracorporeal

Question 34

Struvite

Answer 34

Magnesium ammonium phosphate hexahydrate | - most common in dog, relatively common in cat

Question 35

Infection induced struvite

Answer 35

Most commonly associated with urinary tract infection with urease-producing organisms - staph, proteus, ureaplasmas

Question 36

Sterile struvites

Answer 36

Struvite calculi may (less commonly) occur in the absence of infection

Question 37

Medical management of struvite

Answer 37

- antibiotics - calculolytic diet - urinary acidifiers (bottom 2 are for sterile stones)

Question 38

Calcium oxalate

Answer 38

Most common in cats, most common nephrolith

Question 39

Calcium oxalate contributing factors

Answer 39

- hypercalciuria - hypocitraturia - hyperoxaluria - decreased inhibitors

Question 40

Can you medically get rid of calcium oxalate stones?

Answer 40

No - surgical removal - voiding urohydropropulsion - lithotripsy

Question 41

Medical management of calcium oxalate to prevent recurrence

Answer 41

- find/correct hypercalcemia - dietary modification - urinary alkalinization - thiazide diuretics

Question 42

Dalmation urate urolith formation

Answer 42

Excrete excessive uric acid in urine due to defective uric acid metabolism, and are prone to urate stones

Question 43

Can you see urate stones on x ray?

Answer 43

NO

Question 44

Urate urolith in dalmations - medical management

Answer 44

- calculolytic diet - urinary alkalinisers - xanthine oxidase inhibitors (allopurinol)