Urolothiasis

Question 1

How are Uroliths described/ characterised?

Answer 1

Mineral Component
Location
e.g. cystolith = stone in the bladder

Question 2

How/ When are Uroliths formed?

Answer 2

formed when urine is supersaturated
e.g. tequila salt analogy- more salt in tequila= precipitation & obstruction

Question 3

How can we predict Urolith type based on history, diagnostic imaging and physical exam? (3)

Answer 3

Signalment such as sex, breed, age
Radiopaque or Radiolucency on Radiographs
Urine pH

[or just download the Urolith app lol]

Question 4

What treatments can be considered for Uroliths?

Answer 4

Surgical removal / urinary bypass
Dietary dissolution
Benign neglect

Question 5

How should we treat upper urinary tract uroliths and why?

Answer 5

Surgery as it is hard to dissolve these stones with diet/ medication

Question 6

How would we treat stones in the bladder?

Answer 6

Medical dissolution
Voiding urohydropropulsion
Cystotomy

Question 7

What is the best way to treat urethral stones?

Answer 7

Retrograde flush

Question 8

When is it appropriate to practice medical management for Urolithiasis as opposed to surgery?

Answer 8

If there is no obstruction
No contra indications to diet therapy
If it is a struvite, cystine or urate- these are generally amenable to dissolution

Question 9

What forms of medical management are available?

Answer 9

increase water intake to dilute the urine (lower the concentrations)
alter urine pH with diet or drugs

Question 10

What is urohydropropulsion?

Answer 10

When the bladder is filled with saline, the patient is positioned vertical and bladder agitated to allow stones to settle at the caudal end of the bladder before we initiate bladder emptying

Question 11

What are Struvite stones made from?

Answer 11

Magnesium Ammonium Phosphate

Question 12

Who is most at risk of Struvite crystals? (4)

Answer 12

Females predisposed
Collies, GSD, Samoyed also predisposed
Dogs with a higher alkaline urine pH
Dogs with UTI’s

Question 13

How do struvite crystals appear on diagnostic imaging?

Answer 13

Appear markedly radiopaque and are often large stones

Question 14

What diet modification can resolve Struvite stones?

Answer 14

Low protein diet
(& increased water intake)

Question 15

What is the issue with preventative diets for struvite management?

Answer 15

the diets usually predispose the patient to calcium oxalate stone formation

Question 16

Are calcium oxalate crystals predominantly found in the upper or lower urinary tract?

Answer 16

Upper

Question 17

Which groups are predisposed to Calcium Oxalate crystals formation? (3)

Answer 17

Terriers, Poodles, Schnauzers, Burmese cats
Males predisposed
Older animals

Question 18

What is Laser Lithotripsy?

Answer 18

uses a laser to break kidney stones into tiny pieces

Question 19

What causes the formation of Ammonium Urate crystals? (3)

Answer 19

reduced conversion of uric acid to allantoin
defective transport mechanism of uric acid out of the urine into the liver
hepatic dysfunction

Question 20

How can we treat and prevent ammonium urate crystals?

Answer 20

Reduce purines in the diet by using prescription diets
Give Allopurinol- it inhibits xanthine oxidase which reduces uric acid (must keep dietary protein intake low)

Question 21

How do Ammonium Urate crystals appear on diagnostic imaging?

Answer 21

Radiolucent

Question 22

How do Cystine stones appear on diagnostic imaging?

Answer 22

Radiolucent

Question 23

Why are certain breeds predisposed to Cystine stones?

Answer 23

because they have a renal tubular defect resulting in excess urine cystine which is poorly soluble and forms stones instead

Question 24

How do we treat and prevent Cystine stone formation?

Answer 24

Castration can decrease cystine excretion
Dissolve using diet (but this is expensive)

Question 25

What is the most common stone type in Rabbits and Horses?

Answer 25

Calcium Carbonate

Question 26

When do Calcium Phosphate crystals form?

Answer 26

associated with primary hyperparathyroidism or due to mineralisation of a blood clot