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