Uroliths Flashcards
What are struvite uroliths made of?
Magnesium ammonium phosphate (MAP).
What percentage of lower urinary tract stones in dogs are struvite uroliths?
what are they accosiated with?
What are the main risk factors for struvite uroliths in dogs?
Approximately 40%.
UTIs with urease-producing bacteria,
Risk factors:
* urine retention, conditions predisopsing to UTIs eg diabetes mellitus or hyperadrenocorticism.
* Susceptible breeds – Miniature schnauzer, Shih Tzu, Bichon
What percentage of struvite uroliths in cats are sterile?
what percentage of uroliths affecting cats do stuvite acount for?
what are the risk factors?
90% are sterile, account for 50% of stones affecting cats
Risk Factors
* Abnormal retention of urine
* Formation of concentrated urine – moisture content of food, water intake
* Urine-alkanising metabolites in diets
What are calcium oxalate uroliths caused by?
What are the risk factors for calcium oxalate uroliths?
what percentage of stone affecting cats and dogs do calcium oxalate account for?
- Aetiology poorly understood
Hypercalciuria, hyperoxaluria, and hypocitraturia.
risk factors:
Acidifying diets, calcium supplements outside meals, high protein diets, and concentrated urine.
- Recurrence common
- Account for approx. 40% of stones in dogs and cats
What are urate uroliths composed of?
Which dog breeds are predisposed to urate uroliths?
what are they associated with?
what are the risk factors?
Uric acid, sodium urate, or ammonium urate.
Dalmatians and Black Russian Terriers.
- Often associated with portosystemic shunt PSS – due to impaired hepatic metabolism of uric acid and ammonia - so urate uroliths also associated with breeds predisposed to PSS eg Yorkshire Terriers
Risk factors:
* High Purine intake (glandular meat)
* Persistent aciduria in a predisposed animal
What causes cystine uroliths?
which dog breeds are predisposed?
what is the signalment?
what are the risk factors?
Cystinuria, a metabolic disorder. inborn error of metabolism caused by defective tubular resorption of cysteine and other amino acids
* Breeds with genetic mutations include Newfoundlands, Labradors, Australian cattle dogs, mastiffs and bulldogs
* Not all cystinuric dogs develop cysteine uroliths – cystinuria is a predisposing factor
* Predominantly intact male dogs affected
Risk factors:
* Genetic predisposition to cystinuria
* Acidic, concentrated urine
* Urine retention
What are other, less common types of uroliths?
Calcium phosphate (< 1%) and xanthine (linked to genetic defects or allopurinol therapy).
What are uroliths?
Uroliths, or calculi, are stones found in the urinary tract, primarily affecting the bladder and urethra in dogs and cats.
What are the main clinical signs of uroliths?
What additional signs might occur with urate uroliths?
Dysuria, haematuria, pollakiuria, and possible urinary obstruction.
urate - Symptoms related to portosystemic shunt (PSS).
What is the role of urinalysis in diagnosing uroliths?
It includes pH monitoring, UTI screening, and detecting crystals (though crystal presence isn’t always reliable).
what type of uroliths are radiopaque, why is this important?
Calcium Oxalate, Struvite, Calcium phosphate - make up 80-90% of uroliths - good because can see on Xray
How do struvite and calcium oxalate uroliths differ in radiographic appearance?
Struvite stones are round/smooth, while calcium oxalate stones are irregular.
What diagnostic imaging can detect radiolucent uroliths?
Ultrasound.
Which type of uroliths can be dissolved through dietary management?
what does this diet need to consit of?
Struvite uroliths (with antibiotic treatment for infection-related cases (most of them in dogs).
- diet needs to be acidifying
cysteine and xanthine can also be dissolved with alkanising diets
what is the specific treatment for urate uroliths?
- Allopurinol – Xanthine Oxidase inhibitor – for dissolution – takes at least 4-6 weeks, sometimes required long term
- Not effective if PSS – need to manage the shunt
