Incontinence in small animals Flashcards
Categories - urinary incontinence
- neurogenic/ non-neurogenic
- by presenting sign: congenital, overflow, stress, urge, paradoxical, by response to tx, hormonal
- useful aid to problem solving but not dx
Causes of juvenile canine incontinence
- ureteral ectopia
- congenital USMI
- genitourinary dysplasia
- bladder hypoplasia
- intersexuality
- pervious urachus
- neurological dz
- combinations of above.
Causes of adult canine incontinence
- USMI
- prostatic dz
- neurological dz
- urogenital neoplasia
- fistulae
- bladder atony
- cystitis
- detrusor instability
- pelvic masses
- combinations/ others
Define and decribe USMI
= Urethral sphincter mechanism incompetence
- common cause of incontinence in dogs, esp neutered bitches, although castated male dogs and entire bitches can bee affected
- usually acquired but may be congenital and may occur with anatomical defects (ureteral ectopia, intersexuality)
- usual sign is urine leakage during recumbency
- severity of leakage variable
- often follows neutering
Pathophysiology - USMI
- mutlfactorial aetiology
- medium-large breeds most commonly
- factors: anatomical, hormonal, environmental, unknown
USMI - risk factors
- prevalence 3-12% post-neutering
- 75% cases develop within 3 years of neutering
- certain breeds (irish setter, rottweiler, OESD, doberman)
- docked dogs and dogs >20kg significantly more at risk
- effect of prepubertal neutering unclear
- causal effect on neutering unclear (not d/t adhesions, possibly oestrogen and protegesterone levels and gonadotrophin effects)
Dx - USMIA
- PE unremarkable
- Dx based on hx, CS, investigation, response to trial tx, r/o other causes
- caudally positioned bladder neck is supportive but not diagnostic
USMI in mae dogs
- uncommon
- congenital/acquired
- acquire more likely in castrated larger breeds
- leak predominantly when recumbent (suggests similar mechanism of inreased abdominal pressure –> resting urethral resistane)
- intrapelvic bladder neck adn castrration statistically signficant factors
- responds to medical tx less well than bithc
- sx described
What is ureteral ectopia?
= ureters pass bladder and open into urethra or occasionally into vagina
- congenital > acquired
- inherited/ familial in some breeds (golden retriever)
- females> males
- dogs > cats
- bilateral/unilateral
- openings may be single/ double/ elongated (troughs)
Describe differences between dog/cat ureteral ectopia
- dogs most likely to have an intramural ectopic ureter
- cats usually have extramural ectopic ureter
CS - ureteral ectopia
- continued dribbling urinary incontinence
- may have severe scalding
- frequently associated with UTIs
- may have concomitant SMI
- may have other abnormalities (hydronephrosis, hydroureter, rarely ureterocoeles)
Describe genitourinarydysplasia
- rare cause of urinary incontinence in cats and v occasionally dogs
- more common than ectopic ureters in cats
= congenital developmental abnormality affecting vagina and urethra
Other causes - urinary incontinence - 4
- INTERSEXUALITY: rare cause of juvenile incontinence, incontinence most frequently d/t urine refluxing into another structure, may also get concomitant SMI. Tx depends on underlying defect, frequently sx.
- BLADDER HYPERPLASIA: rare, usually associated with other congenital defects e.g. bilateral ectopic ureters, diagnosed radiographically, signs d/t low volume, poorly compliant bladder –> overflow, guarded px
- BLADDER ATONY: usually secondary to bladder distension, tight junctions in bladder wall disrupted –> atonic bladder and urinary retention with overflow, px guarded, tx requires indwelling catheter.
- PERVIOUS URACHUS: v rare in cats/dogs, more likely in farm spp.
Approach - urinary incontinence
Hx –> PE –> clincail pathology (urine, investigate PUPD if present) –>trial tx if suspect USMI –> diagnostic imaging/ endoscopy
Role of diagnostic imaging in urinary incontinence
- cause urinary incontinence
- result from incontinence
What diagnostic imaging should be used?
- Plain films (RLR, VD)
- IVU (IV urography)
- Retrograde study: most useful as provides most information on intra-pelvic anatomy
- ultrasound: confirm normal ureteral emptying into bladder, additional info on kidneys, bladder, prostate
- others
Outline endoscopy in urinary incontinence diagnosis
- excellent visualisation: ectopic ureters, other lesions of urethra –> bladder neck which may –> incontience. Subjective indication of urethral tone
- can facilitate biopsy
- recently used to tx intramural ectopic ureters using a laser
- no information of urethro-pelvic relationships
- not widely available in UK
Tx - urinary incontinence
- ideally based on definitive diagnosis
- without this tx is TRIAL and SYMPTOMATIC
- not necessarily undesirable provided owners understand this is the case
Medical tx - urinary incontinence
- Tx UTI (base on C+S, confirm eradication)
- Tx underlying systemic dz (PUPD may exacerbate or precipitate condition)
- Diet if obese
- specific medication depends on dx
Medical tx - SMI in dogs
- Phenlypropanolamine = PPA (most effective)
- Ephedrine hydrochloride (cheaper)
»> both of above are alpha-adrenergic agonists
Which disorders have sx options?
- only with definitive diagnosis
- ureteral ectopia
- USMI in dogs (female and male)
- genuto-urinary dysplasia
- congenital genito-urinary malformations
- bladder, urethral or vaginal masses
- prostatic dz
Management pre-sx
- UTI and obesity to be managed 1st
- owners should be given realistic expectations as success not guaranteed
Sx tx options for SMI
- MOST SUPPORT: colposuspension, urethropexy, prosthetic sphincter, endoscopic injection of collagen
- OCCASIONAL REPORTS: vas deferens pexy, urethrocystoplasty (cats), sling urethroplasty, cysto-urethropexy, other transpelvic slings, other variations/ combinations
Principles - sx for USMI
- improve pressure transmission to bladder neck
- increase urethral resistance
- or both