Urolithiasis SA (Byron) (Parts 1 & 2) Flashcards
Calculi (or stones) in the urinary tract
Urolithiasis
(T/F) The lower the urine concentration (specific gravity), the more likely crystals are to form
False, the higher the urine conc.
(T/F) The lower the temperature of the urine, the more likely crystals are to form
True
(T/F) The lower the concentration of inhibitor substances, the more likely crystals are to form
True
(T/F) The lower the excretion of calculogenic substances, the more likely crystals are to form
False, the higher the excretion
(T/F) pH has an impact on the formation of ALL crystals
False, pH can have an impact on the formation of SOME BUT NOT ALL crystals
What stone is extremely sensitive to the pH of the solution?
Struvites, magnesium ammonium phosphate
- in high pH (basic) they are going to precipitate out
- at low pH (acidic) they go back to the solution
What is the MOST common stone in dogs?
Struvite
What is the MOST common stone in cats?
Calcium Oxalate
On what stone does the pH have no effect?
Calcium Oxalate
(T/F) Diet can be beneficial for an animal with Calcium Oxalate
False, no diet will prevent Calcium Oxalate from reforming if they already formed once
List the reasons when Crystals are a Problem:
- If seen in a patient who is a known stone-former
- Patient with lower urinary tract signs
- Male cat with a history of plug formation/obstruction
- Persistent, significant crystalluria noted
- Urate and cystine crystals
Predisposing Factors to stone formation:
- Primarily dogs, Staph spp., struvites
- Cystine, calcium oxalate
- Urate, calcium oxalate
- May predispose, but not a disease in itself
- Infection
- Tubular defects
- Metabolic defects
- Crystalluria
What is the key to diagnosing stones in a patient?
Radiographs
In dogs ________ and ________ are the most radiopaque, and then cystine and urate (may not be very well visible)
struvites, calcium oxalates
In cats ________ are more radiopaque than struvites
Calcium oxalates
coffin shape crystal
struvite
In a cat, struvites occur in the ___________ in sterile urine
bladder
(T/F) 50% of stones in dogs are associated with UTI from Staph spp. and Proteus
True
For what stone, do they belive, there is a genetic component?
Calcium Oxalate
__________ urinary citrate (and Mg and pyrophosphate) can combine with calcium and oxalic acid (soluble) and reduce CaOx (insoluble) production
increased
Hypercalcemia can predispose to:
Hypercaliuria
Oxalate can be absorbed from the:
GI tract
_____________ deficiency can increase urinary oxalate levels
Vitamin B6
(T/F) Dissolution for calcium oxalate is effective
False, dissolution is NOT effective and must be physically removed
What is the end product of vitamin C?
Oxalate
What stone is the following describing?
- Rare in cats
- Frequently recur
- Look for hepatic dysfunction, although not always present (ammonia urate circulating)
Urate
Medical dissolution for urate stones is _________ (useful/not useful) in cats
not useful
In dogs, diet management of urate stones is ___________ (useful/not useful)
useful
What stone is the following describing?
- Very rare in cats
- DSH and Siamese cats
- Defect in renal tubular transport
Cystine
What stone is the following describing?
- Rare (esp. females) but getting more common, frequently recur in dogs
- acidic urine pH
- Defect in renal tubular transport
Cystine
You have an 11-year-old female spayed miniature schnauzer that you just removed 4 calcium oxalate stones from by cystotomy. This was the first time this dog had stones. What sort of post-op plan will you make?
Increase water intake, add potassium citrate to the diet and radiograph every 3 months to monitor for recurrence
Nephroliths in SA
We do not generally remove them unless:
- Recurrent UTI
- Evidence of obstruction of ureter/renal pelvis
- Evidence of pain
Match the ureter sizes with the correct species:
- 1.3 - 2.7 mm diameter
- 1 mm outside, 0.4 mm lumen
- Canine
- Feline
- May indicate previous obstruction and permanent renal damage
- Clinically significant obstruction is often seen on the “BK” side
Big Kidney, Little Kidney
Ureteral are made of smooth muscles, what medications might you use to relax the muscles?
Prazosin - alpha 1 antagonist, can lead to hypotension
Tamsulosin - alpha 1A specific, less risk of hypotension
