Nutrition for Urolithiasis

Question 1

T/F: crystalluria indicates uroliths are present

Answer 1

false – crystalluria alone is not definitive for urolithiasis.

Question 2

When you see bacteria present on your patients UA, what urolith type would you most likely suspect is present?

Answer 2

struvite

Question 3

What urine pH supports struvite stone growth?

Answer 3

alkaline

therefore treatment is to acidify the urine to dissolve the stone with DL-methionine

Question 4

What are nutritional factors you can implement for patients with sterile struvite stones?

Answer 4

1. more water
2. limit dietary precursors (magnesium, protein, phosphorus)
3. enhance NaCl
4. acidify the urine (with diet or suppl. DL-Methionine)

Question 5

If a dog has a struvite stone + a UTI and this is their FIRST episode of struvite, then what is not required in treatment?

Answer 5

dissolution/prevention diet

just manage the UTI.

Question 6

T/F: it may take months for large struvite stones to dissolve via diet.

Answer 6

true

you should continue the diet 1 month past negative imaging.

if the dissolution diet is not working, check with owner compliance, supplement DL-methionine, culture the urine, or reconsider the stone type.

Question 7

What does cranberry extract contain that is helpful for managing chronic recurring UTIs associated with struvite stones? and what is the mechanism of action

Answer 7

proanthocyanidins
they reduce microbial adherence to the bladder wall.

Question 8

What are the 3 ways you can manage recurrent chronic UTIs through dietary managemnet?

Answer 8

1. cranberry
2. d-Mannose powder
3. probiotics (visbiome)

Question 9

What urine pH favors calcium oxalate stone formation and are these stones able to be dissolved?

Answer 9

acidic urine favors formation

they cannot be dissolved, they require manual removal.

Question 10

What breeds are prone to forming calcium oxalate stones?

Answer 10

schnauzers
bichons
shih tzus
lhasa apsos
yorkies
mini or toy poodles

Question 11

What are key nutritional factors to prevent calcium oxalate stones from forming?

Answer 11

1. water!
2. limit dietary precusors (calcium, vitamin D, oxalate, vitamin C)
3. limit protein
4. enhance inhibitors (citrate, magnesium)

Question 12

What are 2 conditions associated with hypercalcemia can lead to calcium oxalate urolith formation?

Answer 12

1. primary hyperparathyroidism
2. feline idiopathic hypercalcemia

Question 13

T/F: many urinary diets are low fat

Answer 13

false – high fat.
so take this into consideration if you have a patient with a history of pancreatitis or lymphangiectasia

Question 14

What can be added to the diet if the patients urine pH is persistently < 6.5 and you want to prevent calcium oxalate stone formation?

Answer 14

potassium citrate.

Question 15

What urine pH supports formation of purine uroliths and are these stones able to be dissolved via diet or medical management?

Answer 15

acidic pH
yes these stones can be dissolved using diet or medical management

Question 16

What are risk factors for purine uroliths?

Answer 16

1. portosystemic shunts
2. UTIs (urease bacteria)
3. acidic or high-protein diet
4. genetic

rare in cats

Question 17

What breed is prone to purine uroliths?

Answer 17

dalmations

Question 18

what is involved in the prevention and dissolution of purine stones?

Answer 18

1. water
2. limit protein (esp organ meat; boiled meat = lower in purines)
3. alkalinize the urine (low protein diet, or vegetarian diet)
4. give antibiotic if UTI
5. give urine alkalinizer (potassium citrate if urine pH <7.0), but monitor K.
6. Allopurinol for dissolution (xanthin oxidase inhibitor)

Question 19

What is used to dissolve purine uroliths?

Answer 19

allopurinol (a xanthase oxidase inibitor) in addition to a low purine diet.

dissolution takes ~14+ weeks.

Question 20

How do you manage cystine stones?

Answer 20

potassium citrate

Question 21

What is involved in the monitoring of a patient with urinary stones?

Answer 21

1. BW/BCS/MCS
2. appetite and behavior
3. urinalysis every 3-6 months
4. urine culture
5. radiographs (every 2-4 weeks during dissolution of struvite and purine stones)
6. determine target urine pH