Micturition Disorders Flashcards
Let’s start slow, the peripheral NS is divided into which groups?
- Autonomic NS (involuntary)
2. Somatic NS (skeletal m- voluntary)
The autonomic NS is divided into parasympathetic and sympathetic. What is the responsibility of each with regards to the bladder?
Parasympathetic: ACh: causes the bladder to contract –> urinate
Sympathetic: Noraadrenalin: causes the bladder to relax –> fill up
-causes the internal m sphincter to contract, keep the bladder full
What is the Somatic NS responsible for with the bladder?
Motor component! ACh causes contraction of the external urethral sphincter
Sensory component
What happens during the passive phase of filling (reservoir)?
Innervated by L1-L4 (hypogastric: sympathetic)
- activate beta receptors to allow stretching - activates alpha 1 receptors of the trigone and proximal urethra - blocks parasympathetic outflow
What happens during the active phase (voiding)?
Reflex: stretch receptors –> pelvic n –> SC –> brain stem –> parasympathetic outflow (pelvic n S1-S3)
Contraction of the bladder wall –> m fibers contract
Pudendal n is inhibited by decreasing urethral sphincter tone
Can be overridden by the cerebrum
I am sitting in class and I have to pee because I always have to pee. I’m holding it in because that’s what’s socially acceptable. What stage am I in?
Active phase: squeezing to hold it in
The following things are associated with UMN bladder or LMN bladder:
- sphincter hyperreflexia
- reflex dyssynergia can also occur
- small volumes of urine
- small bladder
- difficult to express
- lesion about sacral segment
UMN bladder!
How do we tx UMN bladder?
baclofen: anti spasmodic, acts as inhibitory NT, skeletal m relaxant
The following things are associated with UMN bladder or LMN bladder:
- large bladder
- easily expressed
- constantly leaks
- sacral spinal cord segment or pelvic segment lesion
LMN bladder!
How do we tx LMN bladder?
Express bladder 3-4 times/day, bethanecol
How is Detrusor-Sphincter Reflex Dyssynergia initiated and treated?
with initiation of detrusor contraction, the urethral sphincter spasms
tx w alpha adrenergic blockers (phenoxybenzamine)
Is dysautoanomia something we will frequently see in dogs?
No! It is rare but if we do see it, it’s in cats. Poor prognosis
The following things describe what problemo
- occurs from OVERFILL (obstruction)
- large, flaccid bladder
- neurological exam is normal
- tx: manual express
Detrusor atony
What is the issue occurring during Urge Incontinence aka detrusor instability/detrusor hyperreflexia?
-detrusor contraction during storage of urine or low compliance of the detrusor muscle, which may be confirmed by cystyometrography
What are the clinical signs of urge incontinence?
- pollakuria
- stranguria
- dysuria
How do we tx urge incontinence?
anticholinergic: oxybutynin, imipramine or dicyclomine
All of the following describe what problem:
- the involuntary escape of urine during the storage phase of the urinary cycle
- intermittent or continuous dribbling of urine with a normal voiding episode
- loss of voluntary control of urination and consequent leakage of urine
Urinary Incontinence
What’s the MOA for urinary incontinence?
- intravesicular pressure greater than urethral pressure
- anatomical abnormalities
What is the most common etiology of urinary incontinence?
Urinary Sphincter Mechanism Incompetence (SMI)
SMI is responsible for what percentage of urinary incontinence?
85%!
What clinical signs do we see with SMI?
- soiled, perineal coat
- urine scald
- anatomical abnormality
What is our typical signalment and predispositions in SMI?
- typical signalment= spayed bitch
- incidence higher in large breed dogs
- bladder neck position and urethral length may play a role in the development of USMI (everything depends on urethral tone- if you have a longer urethra then the overall pressure is higher which is GOOD as far as holding pee in. If you have a shorter urethra then it will have less pressure and will more likely to drip)
The following pathomechanism describes what:
- pelvic bladders (meaning, >5% of bladder in the pelvis)
- lack of estrogen will decrease sensitive of the smooth m receptors to sympathetic stimulation: ‘estrogen responsive incontinence’
- Reduction in urinary sphincter pressure drops from a mean of 18 to 10 after spaying; if less than 7.5 then will develop this
- Type I smooth m fibers control continence, these decrease substantially after OVH
SMI!!!!
This theory is called what and is associated with what “disease” (idk what it’s considered)
When the urethral neck is not in the abdominal cavity, it is not subjected to the same pressures as the intra abdominal bladder. The bladder pressure exceeds urethral pressure and thus leaking happens.
Pressure transmission theory and is associated with SMI
This theory is called what and is associated with what problem:
The anatomic structures maintaining the position of the bladder and urethra are abnormal.
Hammock theory and is associated with SMI
What are the indications for urodynamic urethral pressure profiles?
- urethral sphincter mechanism incompetence
- detrusor instability
- reflex dyssynergia
- neurogenic abnormalities
How do we intervene with incontinence?
- use bovine collagen
- GAX= acellular bovine dermis-derivative primarily consisting of type I collagen cross liked w glutaraldehyde
- European study: long term outcome found GAX implantation in incontinent female dogs reported that 68% of 40 dogs were continent for 1-64 mos after 1 injection (median 8 mos)
- may necessitate repeated GAX implantation procedures per the dog’s lifetime
What surgical procedure/s can we perform to correct incontinence ?
Colposuspension and urethropexy are current accepted surgical techniques
53% continent after sx
The following clinical signs are associated with what
- wet coat
- inflamed perineum
- excoriations (a break in the skin surface; the act of wearing off skin)
Ectopic ureter
What should we perform prior to sx on a patient with ectopic ureter?
Urethral profilometry
What diagnostic methods have the greatest accuracy for detecting ectopic ureters?
Contrast enhanced (excretory urogram) CT and cytoscopy
What is the tx of choice for ectopic ureters?
Cystoscopic laser ablation
What are the important factors to consider with regards to ectopic ureters? aka why do we care
- can be hereditary
- UTI –> pyelonephritis
- culture and tx infection, need to get rid of the infection before sx
- once treated, clinical signs may persist as USMI accompanies this condition!!
