Week 6- Approach to Urinary Incontinence Flashcards
What occurs during the urine storage phase?
- Bladder fills and relaxes
- Urethral sphincter remains closed
- abnormalities result in urinary incontinence
What occurs during the Urine Voiding phase?
- Bladder contracts
- Urethral sphincter/ Urethra relaxes
Which phase is true urinary incontinence?
Urine Storage Phase
Under what control does the storage phase occur?
under sympathetic control
* Contraction of outflow tract + active relaxation of the detrusor muscle
* Beta adrenergic receptors in the bladder
How is urine stored?
When the outlet tract pressure exceeds the vesicular pressure
What is overflow incontinence?
- Failure of voidance
- Increased Intravesicular pressure
What three things may cause True Incontinence?
- Urethral sphincter mechanism incompetence
- Ectopic Ureters
- Lower Motor Neuron Bladder
What may cause paradoxical incontinence?
- Detrusor atony
- Functional Obstructions…
What is dysuria?
Difficult or painful passage of urine
What is stranguria?
Straining or hesitancy prior to or after urination
What is pollakiuria?
Increased frequency of urination
What is nocturia?
The urge or need to urinate at night
What is enuresis?
unconscious leaking of urine from a sleeping animal
What does a bladder with urethral disease look like?
Stranguria, Tense/ Full bladder
What does a bladder with sacral disease look like?
- Soft bladder
- Easily expressed
- Other neuro signs
What does a bladder with sphincter incompetence look like?
- Soft bladder
- No over-distension
- No stranguria/ dysuria
- No other neuro signs
What may predispose to infection?
Altered Urethral Defence Mechanisms (Sphincter Incompetence)
What two medications relax the detrusor muscle, allowing the bladder to enter the storage phase?
- Phenylpropanolamine
- Oestriol
What is USMI?
Urethra weakens and becomes leaky
Why is USMI more common in spayed bitches?
Lack of estrogen= decreased muscle tone
How would you treat USMI?
- Weight loss
- Therapeutics
- Phenylpropanolamine
- Ephedrine
- Oestriol
What are the aims of USMI Surgery?
Increase urethral resistance: Artificial Urethral Sphincter
(AUS) or collagen implant (intraurethral bulking agent).
* Collagen injected around proximal urethra.
* 70% improve but deteriorate over 12 months.
* Can be repeated but expensive.
* Move bladder neck into abdomen: colposuspension,
urethral sling, transvaginal sling, cystourethropexy.
* Colposuspension: 50% cured, 40% improved.
What is detrusor overactivity?
Rare in small animals – recognised in humans (OAB).
* Bladder fails to relax during storage phase
* Detrusor hyperactivity (neurologic)
* Detrusor instability (non-neurologic)
What is the treatment for detrusor overactivity?
aimed at increasing bladder capacity/decreasing spasticity (voidance).
* Antimuscarinic (anticholinergic) agents (propantheline, oxybutynin)
* Relaxants (imipramine)
What do ectopic ureters result from?
Results from dysembryogenesis of the metanephric ducts.
What are the signs and signalment of ectopic ureters?
Often evident from birth but not always – may be mistaken for
poor house training!
* Continuous incontinence but may be intermittent.
* More commonly seen in bitches.
* Some breed predispositions - WHWT, Border terrier,
Newfoundland, Siberian Husky, Lab and Golden Retrievers
How might you diagnose ectopic ureters?
Urinalysis, but it is susceptible to UTI’s
Radiography or Contrast Radiography
Ultrasonography- may often see a distended ureter (hydroureter/hydronephrosis)
What is the gold standard for diagnosing ectopic ureters?
Transurethral Cytoscopy
How might you treat ectopic ureters?
- Suregery is required for correction
- Intramural EC: transurethral cytoscopic ablation of intramural ectopic ureters
- Nephrectomy if required
What is patent urachus?
Foetal urachus remains patent
* Evident early in life and can be surgically corrected
What is iatrogenic uretovaginal fistulation?
Occurs when a ureter is accidentally incorporated into the vaginal ligature during an
ovariohysterectomy.
* Patient unwell few days post-sx, then incontinent
* Don’t confuse with USMI
* Tx: anastomose ureter to bladder or nephrectomy/ureterectomy.
What is detrusor atony?
Over distention damages tight junctions resulting in weak, uncoordinated or absent bladder contractions
What does detrusor atony look like on a physical exam?
often bladder is large but flaccid.
What is the treatment for detrusor atony?
address any underlying cause, relieve any obstruction
(catheterise if necessary), manually express bladder (neurological cases)
What medication would you use for detrusor atony?
Parasympathomimetics like bethanechol (only effective on intact smooth
muscle cells).
* Relax US: prazosin, phenoxybenzamine (IUS), diazepam (EUS).
What is the prognosis for detrusor atony?
Prognosis dependent on cause: recovery of detrusor reasonable for acute cases but guarded prognosis if chronic.
What is reflex dyssynergia?
Functional abnormality - failure of coordination of sphincter relaxation and detrusor contraction.
* Initiation of detrusor contraction stimulates simultaneous contraction of sphincter muscles.
* Leads to bladder distension → bladder atony, UTIs.
In what dog breeds is bladder dyssnergia most common?
Large and giant breeds of dog
What causes reflex dyssnergia?
neurogenic: lesions of spinal cord; non-neurogenic: idiopathic (‘IRD’: idiopathic reflex dyssynergia)
What is the treatment for reflex dyssynergia?
want to prevent bladder distension and restore normal detrusor contraction.
* Catheterisation
* Parasympathomimetic (bethanechol) to restore detrusor contraction and a sympatholytic agent
(prazosin) to allow sphincter relaxation (decreasing outflow resistance).
* Monitor for UTIs
What does lower motor neuron bladder cause?
storage issue.
* Sacral spinal cord segments and nerve roots + pudendal nerve + pelvic nerve.
* Weakness here causes urine dribbling – not aware that bladder is full, no detrusor tone, can express
bladder easily. Often absent perineal reflex, tail paresis and absent tail sensation.
* Tail pull injury.
* Lumbosacral disease.
* Fibrocartilagenous embolism.
* Neoplasia.
What does upper motor neuron cause?
overflow issue.
* Lesion cranial to sacral segments.
* Bladder distension and increased tone, very difficult to express.
* Overdistension → permanent damage, detrusor atony.
* Can develop reflex micturition.
How might you treat neurological incontinence?
with catheterization, manual expressing, ensure no UTI, relax US (prazosin 0.5mg/kg PO BID,
phenoxybenzamine 0.5mg/kg TID PO, improve contraction with bethanecol.
