Midterm - Lecture 11 Flashcards
What is urolithiasis?
stones in the urethra, bladder, kidney of various species
What gender suffers urethral blockages more?
males due to a narrower urethra
What is a struvite stones characteristics?
tend to be finer sand like particles, composed of MgNH4PO4 6H2O
What species are struvite stones found in?
cats and ruminants
What is a silica urolith stones characteristics?
high in silica, sandy soils
What species are silica urolith stones found in?
ruminants
How are calcium oxalate stones formed?
oxalate formed in body or consumed binds Ca and forms insoluble crystal precipitate
What species are calcium oxalate stones found in?
all species
What species commonly get calcium carbonate mucoprotein stones?
horses and rabits
Where are urate stones commonly found?
dalmations
What species are cystine stones commonly found in?
Newfoundlands and labradors
What do stones form as a result of?
infection, animal somehow fails to make factors that inhibit crystallization, urine solutes rise high enough or pH changes enough to cause precipitation of minerals
How does infection lead to stones?
protein and neutrophils accumulate in urine and form crystals
bacterial urease breaks down urea to NH4 which raises the pH
How do you treat urolithiasis?
- get the animal to produce more dilute urine
- acidify the urine IF stone is more soluble in acid
- avoid over-supplemental with minerals that are contributing to uroliths
How do you get the animal to produce more dilute urine?
add salt to the diet, small effect until about 2-3% salt
How do you acidify the urine?
add anions to the diet; preferably chloride salts
What stones should you acidify the urine for?
struvite, ca phosphate concretions, silicate based stones
Which stones should you NOT acidify the urine for?
ca oxalate (worsens by acid urine), urate crystals, cysteine crystals (acid is a precipitate for cysteine)
In small animals, how do you acidify the urine?
add NH4Cl in small amounts to get the urine pH to 6-6.5
What amino acids are used for acidifying urine in small animals?
methionine and cysteine because they are sulfur containing amino acids
In ruminants and horses, how do you acidify the urine?
use HClproducts, try to get the urine pH below 7
What minerals do you want to avoid that contribute to uroliths?
magnesium, calcium, and oxalate precursors
Which food is better to feed cats in order to prevent uroliths?
Wet food because it contains more ml/g than dry food
What is the typical urine pH of ruminants?
alkaline 7.8-8.5
What are the common causes of uroliths in ruminants?
- sheep ingest soil as the crop grass to ground
- often linked to too much phosphorus in the diet
- sodium oxalate containing plants
- bacterial infection
What are the common causes of horse uroliths?
- high potassium from forages
- calcium carbonate
How does the kidney of a horse play a role in uroliths that it can get?
use the kidney to control blood Ca by excreting excess Ca from diet absorption, the Ca typically stays in the bladder
What is the best way to cure uroliths in horses?
cut calcium in the diet and if that does not work, acidify the urine
What is the cause of cysteine uroliths?
a genetic defect in Newfoundlands, labradors, and some cats that fails to reabsorb cysteine after it is filtered across the kidney
Why do dalmations get urate uroliths?
because they cannot metabolize uric acid
How do you prevent urate uroliths in dalmations?
avoid feeding DNA
What are the attributes of struvite dissolution diets?
- Encourages water intake
- Has higher fat to get metabolic water produced
- Utilizes only animal proteins – higher in S-amino acids and generally better utilized
- Drops urine pH below 6.1 – uses ammonium chloride, calcium chloride, calcium sulfate, DL-methionine
- No excess protein, magnesium and phosphorus
- Few oxides or carbonates minerals
What are the attributes of struvite prevention diet?
similar to struvite dissolution diets but the acidifying action is less
