Urolithiasis and FLUTD Flashcards
what is a urolith?
urinary calculus/stone
primarily inorganic or organic crystalloids
organic matrix
is crystalluria synonymous with urolithiasis?
no
what is crystalluria?
microscopic crystals in urine
does crystalluria cause clinical signs?
no
what is initiation of urolith formation dependent on?
supersaturation of urine with lithogenic crystalloids
what are the theories of urolith initiation?
precipitation-crystallization
matrix nucleation
crystallization inhibition
kidney/bladder stones form by a combination of _________________________________
many small crystals into a larger conglomerate
what factors affect supersaturation?
increased excretion of stone constituent molecules can lead to crystalluria
reduced urine volume
alteration in urine pH
what things inhibit stone formation?
citrate
magnesium
glycosaminoglycans
proteins
what things facilitate stone formation?
low urine volume or abnormal pH
high calcium, sodium, oxalate, and urate
what are the steps of stone formation and growth?
supersaturated urine
nucleation and crystal growth
small crystals
growth and aggregation
large crystals
crystal aggregates
what are the consequences to urolithiasis?
trauma to bladder wall: polyps
incomplete urine voiding
sequestration of bacteria
obstruction
what can calculi be classified by?
location
composition
what are renal calculi?
nephrolithiasis
what are the clinical signs of urolithiasis in the urethra?
dysuria, stranguria
paradoxical incontinence
signs of uremia if blocked
obstruction most common in males
what are the clinical signs of urolithiasis in the bladder?
pollakiuria
stranguria
dysuria
hematuria
inappropriate urination
what are the clinical signs of urolithiasis in the ureters?
may have no clinical signs
dogs: flank pain, painless hematuria
cats: clinical signs associated with hydronephrosis (anorexia, vomiting, weight loss)
what are the clinical signs of urolithiasis in the kidney?
asymptomatic
signs of pyelonephritis
signs of uremia
what stones are common as nephroliths?
calcium oxalate
struvite
how are uroliths named?
mineral if single type
mixed if two or more minerals
compound if different minerals are separated into distinct bands or layers
are struvite calculi radiopaque?
yes
how do dogs get most struvite calculi?
UTIs
how does urease producing bacteria lead to struvite calculi?
hydrolysis of urea leads to increased ammonium ions which increases the urine pH
change in ionization state of phosphorous
high pH leads to precipitation of struvites
struvite crystalluria occurs in ___________________ of healthy dogs, including animals without urinary tract infections
greater than 50%
how effective is medical dissolution of both sterile and infection-induced struvite uroliths?
highly effective
what are some other treatment options if the urolith cannot be bathed in modified urine or infection cannot be eliminated?
voiding urohydropropulsion
surgical removal
lithotripsy for lodged urethral calculi
percutaneous cystolithotomy or cystoscopy
are calcium oxalate calculi radiopaque?
yes
how common are calcium oxalate calculi in dogs and cats?
41% of canine uroliths
42% of feline uroliths
what are some predisposing factors for calcium oxalate calculi?
hypercalciuria
+/- hyperoxaluria
calcium oxalate crystallization inhibitors
acidification of urine
high protein diet
how can you prevent calcium oxalate stones?
decrease urine concentration
avoid urine acidification
avoid diets with excessive protein content
are cystine calculi radiopaque?
no
what cause cystinuria?
inherited proximal tubular transport defect
also includes ornithine, lysine, and arginine
what are the three possible mutations in amino acids transporter genes?
type Ia
type IIa
type IIIa
which breeds get the type Ia mutation in amino acid transport?
newfoundland dogs
landseer
how do you prevent cystine calculi?
neuter
decrease urine concentration
limit animal protein intake
limit sodium intake
increase urine pH
tiopronin: reduces urinary cystine excretion
who does urate calculi occur most commonly in?
dalmations
english bulldogs
black russian terriers
if a dog has urate calculi but is not a breed predisposed to them, what is your next differential?
liver disease: portosystemic shunts, chronic hepatic failure
how do you treat and prevent urate stones?
treat liver disease/portosystemic shunt
decrease urine concentration
promote alkaline urine
limit purine intake
xanthine oxidase inhibitors if therapeutic diet fails
are silica calculi radiopaque?
yes
are urate calculi radiopaque?
often no
are calcium phosphate carbonate-apatite calculi radiopaque?
yes
what is the prevalence of FLUTD?
7-8% of all feline admissions to veterinary hospitals reported
most FLUTD first occurs in cats between _____________ years of age
2 and 6
what are the sings we see with a non-obstructed cat with lower urinary tract disease?
stranguria
dysuria
pollakiuria
hematuria
periuria
males and females
how common is feline interstitial cystitis?
20-50%
uncommon in cats >10 years
what percentage of cats presenting with feline lower urinary tract disease have feline interstitial cystitis?
20-50%
who do we primarily see bacterial cystitis in with cats with feline lower urinary tract disease?
cats older than 10 years
what is the primary cause of feline lower urinary tract disease in cats less than 10 years of age?
60-70% are idiopathic
what is the primary cause of feline lower urinary tract disease in cats more than 10 years of age?
> 50% will have a UTI or urolithiasis
what characterizes idiopathic feline lower urinary tract disease?
hematuria with minimal inflammatory cells in urine
acute or chronic
resolution in 5-7 days
functional
multifactorial
what does a urethral plug form in response to potentially?
underlying inflammation of the bladder and urethra
when is a workup to rule out infection and urolithiasis warranted with feline lower urinary tract disease?
recurrent
response to treatment does not work
_________________ is most widespread and economically important urinary disease of ruminants
urolithiasis
what are the predisposing factors of urolithiasis in small ruminants?
decreased salt or water intake
urinary stasis
urinary tract infection
high urine pH
increased calcium
increased phosphate (goats)
what are the earlier signs of urolithiasis in small ruminants?
blood in urine
stranguria, dysuria
decreased urine production
dribbling urine
tail flagging
abdominal pain
rectal exam: feel pulsation of urethra
what predisposes small ruminants to obstruction?
sigmoid flexure and urethral process
narrowness of male ruminant urinary tract
what is the gold standard treatment of urolithiasis in small ruminants?
tube cystotomy
what is the most common site of obstruction in sheep and goats?
urethral process
what do you see with phosphate in ruminants who are blocked?
normophosphate or hypophosphatemia
why do ruminants have a normal or low phosphate when they are obstructed?
secrete most phosphate into saliva and feces
less urine excretion of phosphorous
what additional clinical signs might you see with hypophosphatemia with urinary tract disease in ruminants?
muscle weakness
rhabdomyolysis
bone pain
intravascular hemolysis
worse prognosis
what makes up uroliths most commonly in ruminants?
phosphatic calculi (struvite or apatite)
when can you get a calcium oxalate stone with regards to calcium?
when there is a low calcium diet
all species
when might you see silica uroliths in ruminants?
pastured ruminants
>50% steers on range in Western Canada: depends on where silica levels are higher in soil
in which species are uroliths uncommon?
horses
what types of uroliths do horses get?
calcium carbonate or phosphate
how does the initiation of a urolith happen?
formation of crystal nidus: nucleation
what makes up the organic matrix in urinary calculi?
serum proteins
uromucoid and matrix substance A
lipids
polysaccharides
other cell derived material
what inhibits stone formation?
citrate
magnesium
glycosaminoglycans
proteins
what are some conditions that contribute to stone formation?
high concentration of salt or other constituent in urine
retention of these salts and crystals in urinary tract for a certain period of time
optimal pH that favors salt crystallization
scaffold for crystal formation
decrease in body’s natural inhibitors of crystal formation
what are the names of calculi based on location?
cystic calculi: bladder
nephrolithiasis: renal
ureterolithiasis: ureteral
urethreolithiasis: urethral
what are the clinical signs of ureteroliths?
may have none
dogs: flank pain, hematuria
cats: hydronephrosis: anorexia, weight loss, vomiting
what is the most common type of ureterolith?
calcium oxalate
what clinical signs are associated with nephroliths?
asymptomatic
+/- hematuria
pyelonephritis signs
uremia signs
should you treat nephroliths in a patient that is asymptomatic?
no
are most struvite calculi in cats sterile?
yes
can you dissolve calcium oxalate calculi?
no
cystine calculi are more soluble in ____________ urine
alkaline
what are the three possible mutations in amino acid transporter genes with cystine inheritence?
Ia: newfoundland dogs, ladseer
IIa: australian cattle dogs, border collie
IIIa: miniature pinschers
what eliminates cystinuria in androgen-dependent cystinuria?
neutering
what are some risks of xanthine oxidase inhibitors?
risk of xanthine urolith formation
