Urinary Tract Flashcards
struvite is more common in males or females?
females
struvite is associated with what bacteria and pH?
urease producing bacteria (urea –> ammonia –> ammonium + OH)
resulting in an alkaline pH –> precipitation of struvite
95% of uroliths are…
struvite and calcium oxalate
calcium oxalate is associ. w/ what urine pH?
acidic urine
what is the most radio-opaque urolith?
calcium oxalate
calcium oxalate is more common in males or females?
males
defective uric acid cycling causes…
urate stones
which stones are radiolucent?
urate and cystine
PSS, Liver failure and dalmations are more likely to have what type of stone?
urate
are silicate stones radiopaque?
yes
what is the only urolith associated with alkaline urine?
struvite
what metabolic dz predispose to calcium oxalate stones?
Cushing’s (hyperA)
which stones look like stars?
silicate
when is medical dissolution of stones possible?
If struvite, urate or cystine stones of a small size.
*Note- if do not have stone for stone analysis - how do you know stone type?
indications of nephrotomy
- nephrolithiasis (if dilated/big)
- haematuria of renal origin
- biopsy needed
3 approaches to sx treatment of ureterolith/ureteral obstruction
- ureterotomy
- resection/anastomosis
- ureteral reimplantation
common complication with ureteral sx
ureter so small and fragile often get ongoing leakage post-suturing
what is the preferred technique for proximal ureteral obstructions?
SUBS
- subcutaneous ureteral bypass system
- is a salvage sx
tx of urethral stones
- flush ureteral stones back into bladder (retro-hydropulsion)
- stone removal via cystotomy
how long should you persist w/ retrohydropulsion of a urethral stone?
no longer than 20minutes
steps of a cystotomy
- Caudal midline coeliotomy - drape in prepuce/vulva
- Pack of urinary bladder w/ moist lap. pads
- Place stay sutures in the apex of the bladder and laterally
- ID the median lig of the bladder and remove this w/ Metzenbaum scissors
- Make a stab incision (11 blade) into the ventral surface of the bladder at the level of the median ligament and extend the incision w/ Metzenbaum scissors
- Remove the stones from the bladder atraumatically (keep stone for analysis)
- Pass a u-cath from the outside (penis) to the level of the obstruction (for a female pass from inside bladder first to help w/ catheterisation)
- Flush urethra retrograde
- Flush urethra normograde
rpt flushes + check for stones - Obtain a bladder mucosal sample for C&S
- Close the bladder in simple interrupted appositional closure 4/0 PDS. (submucosa is strength layer)
- Local lavage
- Close body wall
What diagnostics should you perform post-op *cystotomy?
- stone analysis
- bladder histo/C&S
- rads w/ contrast (for radiolucent stone type)
indications for urethrotomy
- obstructed males (calculi that cannot be retropulsed)
- strictures
2 approaches to urethrotomy in the male
perineal or prescrotal
what location do you perform a urethrostomy in the male?
scrotal - urethra widest and most superficial
- less urine scalding
indications for urethrostomy
- severe urethral or penile trauma
- recurrent obstruction (medical management failed)
- unresolvable obstruction
- stricture
- neoplasia
- penile amputation
complications of canine scrotal urethrostomy
- haemorrhage 3-7d
- stricture ***need magnification to get perfect tissue layer aposition
- dehiscence
- UTI
what is FLUTD?
feline idiopathic/interstitial cystitis
- most common cause for urethral obstruction
- sterile urethral plug or inflammation
current tx strategy of FLUTD male cats?
- IVFT + manage azotaemia
- GA –> Pass U-cath to unblock **can be V. difficult
- Place cystostomy tube to bypass urethra
- Block off tube after a few days to see if cat can urinate
advantages of placing a cystostomy tube in a FLUTD cat?
- you don’t need to leave a U-cath in which causes ongoing inflam
- bladder remains empty to treat detrusor atony
- bypass urethra completely (rests to reduce inflam)
- can occlude to ‘challenge’ bladder intermittently and see if urination through urethra possible
indications of cystostomy
- FLUTD
- urethral obstruction
- damaged/traumatised urethra
- bladder atony
cystostomy technique steps
- Bladder distended
- Small midline skin incision - retraction
- Small midline body wall incision (grid incision) - retraction (Gelpis)
- Visualise bladder surface
- 2-4 sutures through body wall and into bladder (stay sutures)
- Cruciform stab (+)
- Tube fed through - Foley (w/ guide wire)
- Close rectus fascia/sc/skin around tube
- Finger trap
- Closed collection system
ideally a cystostomy tube stays in place for how many days?
14 days minimum to allow fibrous adhesions to abdominal wall
indications for a perineal urethrostomy
- challenge and still no urine
- stricture/unresolvable blockage
- recurrent episodes refractory to medical management
goal of perineal urethrostomy
enlarge the urethral opening to prevent blockage
does PU predispose to a UTI?
no
does PU predispose to incontinence?
no
what is a PU?
amputation of penis and scrotum –> meticulous suturing of urethra to skin to create a large opening
abdominocentesis analysis of a uroabdomen
- elevated creatinine 2.4xserum
- elevated K+ 1.4x serum
- +/- neutrophils, bacteria
management of uroabdomen as medical emergency
- Delay surgery until stable
- Reduce K+: insulin + dextrose, terbutaline, IVFT
- Reduce cardiotoxicity: calcium gluconate
- Peritoneal dialysis/peritoneal catheter (Jackson Pratt Drain) to remove urine
- ABs
what is acquired urethral sphincter mechanism incompetence associated with?
gonadectomised females, older, large breed
prognosis for puppy with urethral sphincter mechanism incompetence
w/ congenital USMI - 50% resolve w/ first oestrus
neutered bitches w/ USMI have a problem with smooth or striated muscle in the urethra?
smooth!
medical management of USMI focuses on what?
the tone of urethral smooth muscle (internal sphincter)
give 2 examples of a-adrenergic agonists used to tx USMI
- phenylpropanolamine
- pseudoephedrine
MOA of a-adrenergic agonists in USMI
that contract the urethra acting on a- receptors
response rate of a-adrenergic agonists to tx USMI
80%
complications ot a-adrenergic agonists tx of USMI
- hypertension
- restlessness
- anxiety
- tachycardia
how does diethylstilboestrol tx USMI?
it improves the smooth muscle sensitivity to a-adrenergic stimulation
response to diethylstilboestrol tx of USMI
65%
complications of diethylstilboestrol tx of USMI
- vulval swelling + attraction to male dogs
- higher doses assoc. w/ bone marrow suppression
success rate of colposuspension to tx USMI
~50%
what does a colposuspension achieve?
the vagina is pexied to the prepubic tendon resulting in bringing the bladder cranially which lengthens the urethra reducing the diameter and increasing resistance
risk of colposuspension
can compress the urethra
success rate of colposuspension + urethropexy to tx USMI
~70%
what is a urethropexy?
urethra pexied to prepubic tendon
success rate of urethropexy to tx USMI
55%
new surgical txs of USMI focus on what?
the tone of the urethral smooth muscle (internal sphincter)
which surgical techniques focus on the physical properties of the urethra to tx USMI?
colposuspension + urethropexy
what agents are used for urethral submucosal injections
teflon/collagen
benefits of artificial hydraulic sphincter tx of USMI
- high success: 91% achieved complete continence
- if medical management fails - good option
- O cannot commit to daily meds $$/time constraints
where should the ureter enter the bladder?
into the trigone
ectopic ureters are usually intramural in dogs or cats?
and extramural in dogs or cats?
intramural dogs
extramural cats
other abnormalities associated with ectopic ureters
- USMI
- hypoplastic bladder
- Secondary hydronephrosis/hyroureter/pyelonephritis
signalment assoc. w/ ectopic ureters
- female
- labs, goldens, huskies, WHWT, poodles, newfies, bulldogs
common findings assoc. w/ ectopic ureters
- perivulvar staining
- UA: concurrent UTI, crystalluria
- incontinent since puppy - positional/nocturia
what imaging modality is necessary to determine surgical approach to ectopic ureters?
contrast CT
4 options to tx ectopic ureters
- Neoureterostomy - new opening
- Ureteroneocystostomy - ureteral re-implantation
- Laser-guided ablation (for intramural only)
- Nephroureterectomy - remove kidney and ureter
prognosis after sx treatment of ectopic ureters
- Often not a cure: 22-67% full restoration of continence
2. Ongoing medications: further 7-28% improvement
common causes of a urethral prolapse
Young, intact bulldogs and yorkies
+ Excitement
+ UTI
surgical approach to urethral prolapse
- resection of redundant mucosa + anastomosis to penile mucosa
- urethropexy
+ castrate –> sexual excitement causing over-protrusion
common canine renal neoplasias
- carcinoma, sarcomas, nephroblastomas
nodular dermatofibrosis is associated with what dog breed?
GSD
most common renal neoplasia of cats
lymphoma
technique of renal biopsy
tangential to surface to sample cortex only!
indications for nephroureterectomy
- severe hydronephrosis or pyelonephritis
- haemorrhage
- neoplasia
- cysts
CHECK FUNCTION OF CONTRALAT KIDNEY!
3 types of malignant bladder neoplasias
TCC (most common)
SCC
Leiomyosarcoma
benign bladder neoplasias?
leiomyoma, fibroma
polyp
Ddx. for urolithiasis
bladder neoplasia causing a partial or complete obstruction
what condition to sx tx bladder neoplasia by partial cystectomy
trigone is unaffected and neoplasia benign
what drugs can be used to medically tx bladder neoplasia?
piroxicam + cyclophosphamide
