Urolithiasis

Question 1

What urine type predisposes to urolith formation?

Answer 1

Supersaturated/concentrated urine

Question 2

What is the order of formation of a urolith?

Answer 2

• Supersaturation
• Precipitation of a nucleus
• Crystal growth and aggregation
• Calculus retention

Question 3

T/F: If the animal has crystals in its urine that means it has uroliths?

Answer 3

False- it means that the urine is supersaturated

Question 4

T/F: Crystals may form in stored urine.

Answer 4

True- always check urine soon after sampling

Question 5

T/F: Radiographs are always diagnostic or urolithiasis.

Answer 5

False- Only CaOx and Struvite show up

Question 6

Is nutritional therapy always helpful for treating uroliths?

Answer 6

No

Question 7

What is voiding urohydropropultion?

Answer 7

Filling the bladder and aggressively emptying it manually

Question 8

What is required with voiding voiding urohydropropultion?

Answer 8

Small stone size- must be able to fit through the urethra

Question 9

What kind of animal does voiding urohydropropultion work best on?

Answer 9

Female dogs- can take 5-15mm

Question 10

What is the objective of retrograde urohydropropulsion?

Answer 10

Push uroliths obstructing the urethra back into the bladder where they can be dealt with easier with sx or dissolved

Question 11

What are the different urolith types?

Answer 11

• Struvite
• Calcium oxalate
• Cystine
• Urate
• Silicate
• Mixed/compound

Question 12

What is the composition of struvite crystals?

Answer 12

Magnesium ammonium phosphate hexahydrate

Question 13

Where are struvite crystals usually found?

Answer 13

Mainly lower tract, occasionally upper

Question 14

What are struvite crystals typically associated with in dogs?

Answer 14

Urinary tract infections with urease producing bacteria

May also be breed related- mini schnauzers, shitzu, mini poodle, cocker spaniels, lhasa apso

Question 15

What are struvite crystals typically associated with in cats?

Answer 15

Diet

Question 16

What do struvite uroliths look like?

Answer 16

Big, smooth, radiodense (less radiodense than CaOx)

Question 17

What is the therapy of choice for struvite uroliths/crystalluria?

Answer 17

Dietary

Lower pH and dilute urine

Question 18

What is a worry with dietary therapy in struvite cystals?

Answer 18

Predisposing to CaOx

Question 19

Which hills diet treats and which prevents struvite crystals?

Answer 19

Treatment- s/d

Prevention- c/d

Question 20

What animals are most prone of calcium oxalate crystals?

Answer 20

Male dogs

Question 21

What kinds of things can predispose to calcium oxalate crystals?

Answer 21

Acidifying diets
Obesity
Hypercalciuria
Breeds

Question 22

What do calcium oxalate crystals look like?

Answer 22

Small, very radiodense

Spiney and rarely cause obstruction

Question 23

What are the treatments for calcium oxalate crystals?

Answer 23

Therapy for hypercalcemia

Surgery, lithotripsy, cystoscopy

Question 24

How do you prevent calcium oxalate crystals?

Answer 24

High pater diet, potassium citrate, thazide diuretics, avoid vitamens C and D

Question 25

What is potassium citrate?

Answer 25

Binding agent for dietary calcium

Question 26

Why do most animals get ammonium urate and xanthine (purine) crystals?

Answer 26

Hepatic disease (PSS or cirrhosis) or genetic tubular defects

Question 27

What breeds are predisposed to urate crystals?

Answer 27

Dalmatians, and black russian terrier

Question 28

What predisposes certain breeds to urate crystals?

Answer 28

Decreased uptake of uric acid from hepatocytes to recycle properly to allantoin

Question 29

What urine pH favors urate and xanthine crystal formation?

Answer 29

Low pH

Question 30

T/F: Urate crystals can be diagnosed with radiography.

Answer 30

False- they are radiolucent

Question 31

What therapy should be followed for urate stones?

Answer 31

Dietary dissolution- low protein, increase pH ( potassium citrate and sodium bicarb)

Question 32

What breed are xanthine oxidase inhibitors used in?

Answer 32

Dalmatians- decreases uric acid production Die effects- hyper sensitivity, toxic epidermal necrolysis

Question 33

What disease process is supportive of a diagnosis of urate stones?

Answer 33

Hepatic dysfunction

Question 34

What is the percentage of cystine calculi?

Answer 34

1-8%

Question 35

What breeds are predisposed to cystine calculi?

Answer 35

Australian cattle dogs, dachshunds, newfoundlands, bulldogs

Question 36

What is the pathopysiology of cystine calculi formation?

Answer 36

Defective tubular carrier proteins that are supposed to reabsorb cystine

Question 37

T/F: Cystine calculi are radioopaque.

Answer 37

True- but are very hard to see on radiographs so not clinically useful if suspected

Question 38

What drugs are used to treat cystine calculi?

Answer 38

Thiol drugs- big risks, must talk to owner first

Question 39

What can be done to the diet to help manage cystine calculi?

Answer 39

Alkalinize the urine and low protein diet

Question 40

What condition is usually implicated in calcium phosphate uroliths?

Answer 40

Primary hyperparathyroidism

Question 41

What diets will result in silica uroliths?

Answer 41

Using plant as primary protein sources (rice and soybean), cheap diets with improper protein