Chapter 118 USMI Flashcards
What is most common cause of inconitnence in adult bithches?
And juvenile?
USMI
Ectopic ureters (next most common, USMI)
Describe the innervation to be bladder
List 4 factors that contribute to urinary continence
- Tone in urethral smooth muscle
- Tone in striated muscle
- Natural eleasticity of urerthal wall
- Physical properties of the urethra (e.g. length, diameter, pelvic diaphragm)
When does urinary continence occur?
When intravesicular pressure involuntarily exceeds that exerted by the urethral sphinters
What type of receptors ‘innervate’ the external urethral sphinter?
Nicotinic cholinergic
What might be caused for congenital USMI in cats?
Andmale dogs?
Abnormally short or absent urethra
Diverticula and dilations
List 6 factors thought to contribute to the development of USMI
-
Urethral tone and length
- USMI dogs have lower urethral pressure
- Shorter urethras
- Tail docking
-
Bladder neck position
- Pelvic bladder
-
Body size and breed
- Large and giant breeds x7 more liekly
- Doberman, Old english and Irish setter
-
Gonadectomy
- Neutering x8 increased risk (according to tobias, x2.2 according to O’neill JSAP 2017)
- Neutering –> more collagen, less muscle
- Hormonal status
-
Genital conformation
- Vestibulovaginal stenosis? Recessed vulva? May exacerbate signs
What 2 breeds are at risk of USMI in UK, according to tobias?
And according to O’Neill JSAP 2017
Tobias: Doberman + Old English Shepdog
O’Neil JSAP 2017: Irish setter (OR 8.09) and Doberman (OR 7.98)
In O’neill JSAP 2017, what was overal rate of urinary incontinence
3.14%
What should be performed in USMI work up?
- PE inc rectal and vaginal exam + vulva insoection
- Haem + Biochem
- Urinaysis + culture + susceptibility
- Advanced imaging to rule out other causes of incontinence
What two drugs can be used in the medical management of USMI? How do they work?
- Phenylpropanolamine (Propalin) = alpha-adrenergic agonist –> increased sphinter tone
- Oestrogen (Incurin) = may improve smooth muscle tone and contractility (dont use in juvenile USMI)
- (GnRh agonist (e.g. deslorelin) also shown to temporarily restore continence in USMI bitches.
IN general, what is cure rate with single therapy treatment (i.e. single sx therapy)
50%
How are surgical treatments for USMI broadly categorised. List specific tx options for each category
-
Increase urethral length or relocation of baldder neck
- Colposuspension
- Urethropexy and cystourethropexy
-
Increase urethral resistance
-
Bulking agents
- Teflon originally but –> peritoneal granuloma
- Bovine cross-linked collagen. Now out of production
- Dextranomer/hyaluronic acid co-polymer reported by Lüttman JSAP 2019 (previosuly collagen –> 71% success rate at 6 months, dextranomer/HA co-polymer –> 58% success)
- Transpelvic urethral sling
- N.B sling passed between urethra and vagina, through obrturator foramen and secured ventral midline pelvis
- Transobtruator vaginal tape
- Artificial urethral spincter
-
Bulking agents
What structures need to be avoided during palceemnt of colposuspension sutures?
External pudendal vessels
Where are colpo sutures placed
Insert approx 1-1.5cm lateral from midline (avoiding external oudendal vessels), into side of vaginal (after it has been pushed cranially by insertion of finger/poole suction tip into vestibule/vagina), then back out (ideally 2 sutures each side in average sized dog)