Urinary incontinance in small animals Flashcards
incontinence - define
involuntary passage of urine
can be categorised as __
Neurogenic / Non neurogenic
causes - juvenile - from most to least common
Ureteral ectopia Congenital USMI Genitourinary dysplasia Bladder hypoplasia Intersexuality Pervious urachus Neurological disease Combinations of above
causes - adult - from most to least common
USMI Prostatic disease Neurological disease Urogenital neoplasia Fistulae Bladder atony Cystitis Detrusor instability Pelvic masses Combinations / others
Urethral sphincter mechanism incompetence (USMI)
especially neutered bitches, although castrated male dogs and entire bitches can be affected
Most commonly acquired but may be congenital and may
occur with anatomical defects such as ureteral ectopia and intersexuality
Usual sign is urine leakage during recumbency
Severity of leakage variable
Often follows neutering
USMI - pathophysiology
Multifactorial aetiology
Medium to large breeds most commonly affected, but
can affect a wide range of other breed
hormonal, anatomical, environmental + unknown factors
USMI - risk factors
3-21% post neutering
75% of cases develop within 3 years of neutering
Some breeds more predisposed
Docked and dogs > 20kg significantly more at risk
Effect of prepubertal neutering unclear
Causal effect of neutering unclear - not adhesions, Oestrogen, Gonadotrophin and progesterone levels may have some effect
USMI - diagnosis
PE usually unremarkable History Clinical signs Investigation Response to trial treatment A caudally positioned bladder neck is supportive but NOT diagnostic
USMI in male dogs
congenital or required
leak when recumbent
Intrapelvic bladder neck and castration statistically significant factors
Responds to medical treatments less well than the bitch
Surgical treatments have been described
ureteral ectopia
Ureters by pass bladder and open into urethra or occasionally into the vagina
Usually congenital but may be acquired
unilateral/bilateral
types of ureteral ectopia
intramural or extramural
ureteral ectopia - clinical signs
Continual dribbling urinary incontinence
May have severe scalding
often have UTIs
may also have hydronephrosis, hydroureter and rarely ureterocoeles
Genitourinary dysplasia
Congenital developmental abnormality affecting vagina and urethra
bladder hypoplasia
small bladder - poor reservoir capacity
Diagnosed radiographically
Signs due to low volume, poorly compliant bladder - overflow
Guarded prognosis
intersexuality
Rare cause of juvenile urinary incontinence.
Incontinence most frequently due to urine refluxing into another structure
May also get concomitant SMI
Treatment dependent upon underlying defect but frequently surgical
pervious urachus
V.rare in cats and dogs, seen in farm species
bladder atony
Usually secondary to bladder distension
Tight junctions in bladder wall disrupted - atonic bladder and urinary retention with overflow
Prognosis guarded
Treatment requires indwelling catheter
most useful part of retrograde study
providing information on intrapelvic anatomy
ultrasound
confirming normal ureteral emptying into the bladder
additional information on kidneys, bladder and prostate
endoscopy
Ectopic ureters
Other lesions of the urethra / bladder neck
subjective indication of urethral tone
Can facilitate biopsy
Recently been used to treat intramural ectopic ureters by using a laser
Does not give information on urethro pelvic relationships
treatment of urinary incontinence
based on definitive diagnosis
trial + symptomatic
medical treatment
Treat urinary tract infection – based on culture and sensitivity, successful eradication should be confirmed
Treat underlying systemic disease – PU/PD may exacerbate or precipitate condition
Diet if obese
Specific medication dependent on diagnosis
drugs
Phenylpropanolamine - effective Ephedrine hydrochloride Oestriol - less risk of adverse effects Diethylstilboestrol Ethinyloestradiol Oestradiol benzoate testosterone
Drugs to reduce urethral tone
Phenoxybenzamine
Diazepam
Drugs to improve bladder tone / contractility
Bethanecol
surgical treatment - for which diseases
Ureteral ectopia Urethral sphincter mechanism incompetence in dogs Genito-urinary dysplasia Congenital genito-urinary malformations Bladder, urethral or vaginal masses Prostatic disease
general surgery aims - USMI
Improve pressure transmission to bladder neck
Increase urethral resistance
Colposuspension
Aims to move and retain bladder neck into an intra-abdominal position to allow equal pressure transmission to bladder and proximal urethra
increases urethral resistance
Bladder neck repositioned to an intra-abdominal position and fixed with non absorbable sutures from the prepubic tendon to the vagina
urethropexy
Similar to the colposuspension but sutures placed from urethra to prepubic tissues
Bladder neck relocated and fixed cranially
Prosthetic sphincters
increase urethral resistance
Inflatable band placed around bladder neck
Filled with saline via a subcutaneous port to achieve right amount of resistance
Allows post operative ‘tweaks’ to achieve continence
collagen
Collagen injected into peri-urethral tissues to increase urethral resistance
May be done at open surgery or via an endoscopic injector
Collagen gets degraded over time
surgery for ureteral ectopia - Re-implantation of ureter
create neo-ureterocystostomy for intra mural ureters
Ureteral transection and re-implantation for extra mural ureters
Ureteral transection and re-implantation for extra mural ureters
Continued incontinence Ascending infection and pyelonephritis Bladder oedema and dysuria Stenosis of new stoma Recanalisation of ligated distal ureter Wound breakdown
