Ch 115 - Ureters Flashcards
What % of felines have circumcaval ureters?
- Right 30.6%
- Left 1.3%
- Bilateral 3.3%
7% have a double cava
List the layers or the ureter
- Outer adventitial layer
- Central muscular layer
- Inner mucosal layer (lamina propria and transitional epithelium)
What is the response in terms of ureteral pressure in response to acute ligation?
Ureteral pressures increase and peak by 5 hours and then lessen but remain elevated for 12-24hr
What is the response of renal blood flow after acute ureteral ligation?
- 24hr - 40% of normal
- 2 weeks - 20% of normal
Results in a decreased GFR and a compensatory increased GFR in the contralateral kidney
What cellular response is seen in response to acute ureteral ligation?
- Influx of macrophages and T-lymphocytes
- Macrocyte proteolytic enzymes and cytokines resilt in fibroblast recruitment and activation
- Interstitial fibrosis or glomerulosclerosis
What is the expected return of GFR after ureteral obstruction in previouslt healthy kidneys?
- 1 week obstruction - 65% of normal GFR over 5wk
- 2 week obstruction - 46% of normal over 4m
Slight, moderate and severe fibrosis occurs over 1, 2 and 3 weeks respectively
List important points to discuss with the owner in a cat with ureteral obstruction
- Cannot predict how long the obstruction has been presetn and how well the cat will recover
- Most have some degree of chronic interstitial nephritis which will progress despite surgery
- If azotaemic with unilateral obstruction, cat has bilateral kidney disease
- Significant risk of complications - overall mortality 18-21%
List options for surgical management of ureteral obstruction
- Ureteral resection with reimplantation
- Ureterotomy
- Double-pigtail ureteral stent
- SUB
- Ureteral resection and anastomosis
- Lithotripsy
What % of cats need removal or replacement of a double pigtail stent?
27% - stent occlusion or dysuria
List complications associated with a SUB
- Urolith occlusion 13%
- Occlusion with blood clot under 3%
- Kinking 3%
- Urine leakage - rare
- Infection
- Migration into intestines
What is the % of reported urine leakage after a ureterotomy?
6-12%
May heal on its own with draining from an abdominal or nephrostomy drain
What are the most common ureteroliths in dogs?
- Struvite and calcium oxalate
What is the most common primary ureteral neoplasia in dogs?
Benign fibroepithelial polyps
DDx: leimyoma, TCC, sarcoma, MCT
Where are congenital ureteral strictures most commonly located?
Ureteropelvic junction
What is a urinoma?
What is the treatment?
A collection of urine within the retroperitoneal space that causes fat necrosis and subsequent reactive fibrosis
Tx: ureteronephrectomy with ablation or omentalisation of the urinoma cavity
What breeds and sex are overrepresented for ectopic ureters?
- Skye terriers
- Golden retrievers
- Labs
- Huskies
- Newfies
- Bulldogs
- WHWT
- Fox terriers
- min and toy Poodles
Females are 20x more likely
What is the sensitivity and specificity of CT for diagnosing ectopic ureters?
What other imaging technique is highly valuable?
- 91 and 100%
- Endoscopy of the vagina, urethra and bladder
What is the prognosis after surgical repair of ectopic ureters?
- Continence in 22-72%
- Additional 7-28% become continent with medical management
Those with continued incontinence likely have a functional abnormality of the bladder neck and urethra
List the treatment options for ectopic ureters
Neoureterocystostomy (extramural)
- End-to-side intravesicular or extravesicular
- Side-to-side
Cystoscopic guided laser ablation (intramural)
How does the prognosis of ectopic ureters differ for males as apposed to females
Males seem to have a better outcome
- 5/5 and 9/11 continent after neoureterocystostomy
- 4/4 continent with laser ablation
- Longer urethra, increased pressure within prostatic urethra
What is the major difference regarding ectopic ureters in cats vs dogs
Majority of cats are extramural
What is a ureterocoele?
What are the subtypes?
Treatment?
Dilatation assoc with the distal ureter or ureteral orifice that occurs as a faulty embryonic development (Chwalla membrane fails to regress)
- Orthotopic/intravesicular - Ureteral orifice in normal positionand entire ureterocoele is within the bladder
- Ectopic - If any portion of ureterocoele is within the bladder neck or urethra
Treatment: Resection of the ureterocoele (ureterocoelectomy) +/- neoureterocystostomy (if ectopic)
What is used as a temporary stent when suturing a ureterotomy site?
2-0 to 4-0 suture material
What are the 2 options for end-to-side neoureterocystostomy?
- Intravesicular - vental cystotomy performed to pull ureter from outside in and suture mucosa to mucosa after spatulating the ureter
- Extravesicular - no cystotomy required, sutured to mucose with knows external
Cats with contralateral nephrectomy had creatinine concentrations reduce more rapidly with extravesicular technique
List options for tension reduction for a neoureterocystostomy
- Renal descensus
- Pexy apex of bladder to caudal pole of kidney
- Pexy apex of bladder to iliopsoas muscle (psos cystopexy)
What is the prognosis for reimplantation vs ureterotomy
- Similar rates of uroabdomen (15% reimplantation vs 16% ureterotomy)
- Persistent obstruction more common after reimplantation (11% vs 3%)
What is the reported reduction in GFR after a nephrotomy in feline kidneys?
- 10-20% reduction over 78 weeks
