Urolothiasis Flashcards
How are Uroliths described/ characterised?
Mineral Component
Location
e.g. cystolith = stone in the bladder
How/ When are Uroliths formed?
formed when urine is supersaturated
e.g. tequila salt analogy- more salt in tequila= precipitation & obstruction
How can we predict Urolith type based on history, diagnostic imaging and physical exam? (3)
Signalment such as sex, breed, age
Radiopaque or Radiolucency on Radiographs
Urine pH
[or just download the Urolith app lol]
What treatments can be considered for Uroliths?
Surgical removal / urinary bypass
Dietary dissolution
Benign neglect
How should we treat upper urinary tract uroliths and why?
Surgery as it is hard to dissolve these stones with diet/ medication
How would we treat stones in the bladder?
Medical dissolution
Voiding urohydropropulsion
Cystotomy
What is the best way to treat urethral stones?
Retrograde flush
When is it appropriate to practice medical management for Urolithiasis as opposed to surgery?
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
What forms of medical management are available?
increase water intake to dilute the urine (lower the concentrations)
alter urine pH with diet or drugs
What is urohydropropulsion?
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
What are Struvite stones made from?
Magnesium Ammonium Phosphate
Who is most at risk of Struvite crystals? (4)
Females predisposed
Collies, GSD, Samoyed also predisposed
Dogs with a higher alkaline urine pH
Dogs with UTI’s
How do struvite crystals appear on diagnostic imaging?
Appear markedly radiopaque and are often large stones
What diet modification can resolve Struvite stones?
Low protein diet
(& increased water intake)
What is the issue with preventative diets for struvite management?
the diets usually predispose the patient to calcium oxalate stone formation
Are calcium oxalate crystals predominantly found in the upper or lower urinary tract?
Upper
Which groups are predisposed to Calcium Oxalate crystals formation? (3)
Terriers, Poodles, Schnauzers, Burmese cats
Males predisposed
Older animals
What is Laser Lithotripsy?
uses a laser to break kidney stones into tiny pieces
What causes the formation of Ammonium Urate crystals? (3)
reduced conversion of uric acid to allantoin
defective transport mechanism of uric acid out of the urine into the liver
hepatic dysfunction
How can we treat and prevent ammonium urate crystals?
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)
How do Ammonium Urate crystals appear on diagnostic imaging?
Radiolucent
How do Cystine stones appear on diagnostic imaging?
Radiolucent
Why are certain breeds predisposed to Cystine stones?
because they have a renal tubular defect resulting in excess urine cystine which is poorly soluble and forms stones instead
How do we treat and prevent Cystine stone formation?
Castration can decrease cystine excretion
Dissolve using diet (but this is expensive)
What is the most common stone type in Rabbits and Horses?
Calcium Carbonate
When do Calcium Phosphate crystals form?
associated with primary hyperparathyroidism or due to mineralisation of a blood clot
