Urinary Incontinence Flashcards
Describe the nerves and muscles involved in bladder filling and storage
- Primarily sympathetic via hypogastric nerve
- Beta-adrenoreceptors in the detrusor muscle (relaxation)
- Alpha-adrenoreceptors in the urethral smooth muscle and trigone (contraction) - Somatic (voluntary) nervous system via the pudendal nerve
- Urethral striated muscle contraction
- Inhibition of the detrusor reflex
Describe the nerves and muscles involved in bladder emptying
Parasympathetic nervous system predominates via the pelvic nerve
- Stimulation of stretch receptors in the bladder wall
- Contraction of the detrusor muscle
- Relaxation of the urethral muscle (Detrusor reflex)
How is urinary continence maintained?
Cerebral cortex gives voluntary control by over-riding the detrusor reflex
How is urinary incontinence investigated?
Detailed history
Clinical examination
Biochemistry and haematology
Felv test (cats)
Urinalysis
Urine culture and sensitivity
Observe patient urinating
How can urinary incontinence be further investigated?
- Plain abdominal radiographs - Useful screening procedure (eg. calculi?)
- Intravenous urogram/CT angiography - Essential to achieve opacification of kidneys and ureters
- Retrograde (vagino) urethrogram
- Ultrasound examination of the urinary tract
- Urethroscopy/cystoscopy?
What are the typical findings in a patient with abnormalities of the filling phase?
Patients can urinate normally
Patients can empty bladder normally
Patients dribble urine between urinations
Patients often have reduced bladder capacity
List the DDx for abnormalities of the filling phase
- Congenital or acquired ectopic ureter
- Reduced pressure at the bladder neck: congenital or acquire USMI, intrapelvic/caudal bladder, short urethra, hypoplastic bladder (probably all part of USMI), bladder neck mass, urethral dysplasia
- Involuntary contractions: bacterial infections, cystitis, drug induced
What are the typical findings in a patient with abnormalities of the emptying phase?
Distended bladder
? Constant dribbling of urine
Often no normal urination
List the DDx for abnormalities of the emptying phase
Partial/complete urethral obstruction
Chronic distension of bladder
- Urethral obstruction
- Pelvic trauma
- Intervertebral disc protrusion
- Feline dysautonomia: idiopathic polyneuropathy
Define dyssynergia
Urethral spasm during bladder contraction, urine dribbling, ddx: urethral obstruction, tx: muscle relaxants
What is urethral sphincter mechanism incontinence
- Commonest cause of incontinence in bitch
- Intermittent involuntary passage of urine
- Incontinence usually whilst dog is relaxed (lying down/sleeping)
- Do not constantly dribble urine, can urinate normally
- Acquired and congenital forms
Describe the aetiology of USMI
Low urethral tone: striated m. tone reduced
- ? Hormonal influence
- Spayed bitches
- Prior to 1st season
- Obesity
- Intrapelvic bladder
Acquired USMI is more commonly seen in which dogs?
Usually medium/large breeds
- Dobermans
- Boxers
- Irish setters
- OESD
Usually neutered females
Can occur long time after spay
Congenital USMI is more commonly seen in which dogs?
- Juvenile bitches (prior to 1st season)
- 50% resolve after 1st season (don’t spay these bitches until after 1st season)
- Ectopic ureter is main ddx for this condition but both conditions can be present
How can USMI be medically managed?
- Increase muscle tone
- Phenylpropanolamine or ephedrine
- Estriol (alone or in combination with above drugs) - Reduce contributing factors
- Weight loss
- Treat secondary UTI
How can USMI be surgically managed?
- Colposuspension (relocation of bladder neck cranially, increase in functional urethral length)
- Urethropexy (relocation of bladder neck cranially, increase in urethral resistance)
- Colposuspension and urethropexy
- Artificial urethral sphincter (hydraulic occluder) (constant low level of urethral compression)
- Submucosal urethral injections of bulking agents (increase in urethral resistance)
Describe acquired USMI in male dogs
Uncommon
Usually older, castrated medium/large breeds
Usually overweight
How is acquired USMI in male dogs treated?
Phenylpropanolamine or ephedrine
Oestrogen based dugs?
Weight loss
Surgery
What are ectopic ureters?
Congenital anomaly, ureter bypasses bladder to empty into urethra, vagina or rectum
- Intramural
- Extramural
Describe the predispositions of ectopic ureters
80-90% are unilateral
Intramural more common
Female: male 20:1
Golden/Labrador Retrievers, Skye terriers, Siberian Huskies have greater incidence
Describe the physical exam of a patient with ectopic ureters
Particular attention should be paid to the following areas:
1. External genitalia
- Wet or dry?
- Inflamed?
- Normal in appearance?
2. Abdominal palpation
- Palpable bladder?
How can ectopic ureters be treated?
- Treatment of associated UTI
- Early surgical management (before irreversible secondary changes)
- Technique depends on whether uni/bilateral and intra/extramural ectopia, and secondary changes
- Exploratory coeliotomy
- Cystotomy to assess trigone area
What is the most common cause of feline urinary incontinence?
Neurogenic
eg. tail pull, sacral fracture
Poor prognosis if no improvement after 6 weeks
What are the three types of ureter obstruction
- Intraluminal
- Ureteric calculus
- Pedunculated mass - Intramural
- Tumour (very rare)
- Fibrosis/stricture - Extramural
- Compression or invasion by abdominal tumour/mass
- Ligation during spey (!)
- Uterine stump infection
What condition can develop following prolonged ureter obstruction?
Hydronephrosis
How is uretic trauma definitively diagnosed?
Intravenous urography
How is uretic trauma/avulsion treated?
Correct electrolyte/metabolic abnormalities
Management depends on site and severity of injury
