Urinary 5

Question 1

What happens in the storage phase of the bladder (physiology)

Answer 1

Sympathetic output via hypogastric nerve stimulates
1) Beta receptors in detrusor activated to cause relaxation of bladder
2) Alpha receptors in urethral smooth muscle activated to cause contraction and stop leakage

Question 2

How is voluntary control of urinary done

Answer 2

HIgher cortex via pons and spinal cord activates pudendal nerve
- Pudendal nerve acts on nicotonic receptors on urethral striated muscle to keep it closed and prevent urination

Question 3

How does the physiology behind bladder emptying work after it is full

Answer 3

Stretch receptors in bladder wall are activated and signal to CNS to activate pelvic nerve (parasympthetic)
- Pelvic nerve activates muscarinic receptors on destrusor muscle to cause contraction

+ the pons mediates inhibition of the alpha receptors on the urethra to allow relaxation; inhibitino of symp nervous system

Question 4

Difference in urethral anatomy between males and females

Answer 4

Females have short urethra and only distal 1/3 has striated muscle
vs mlaes have longer urethra and distal 2/3 has striated muscle

So females much more prone to urinary incontinence

Question 5

What are cats less prone to urethral incontinence

Answer 5

Because they have a narrow urethra which provides resistance

Question 6

What is the most common congenital vs acquired cause of urinary incontinence

Answer 6

Congenital = ectopic ureters
Acquired = urethral sphincter mechanism incompetence

Question 7

Where should ureters enter the bladder and what are the two ways we can get ectopic ureters

Answer 7

Should enter at trigone
- Can have intramural ureters that travel through bladder wall to uretha; this is more common in dogs
- Can have extra-mural ureters which miss the bladder and enter directly into ureter; more common in cats

Question 8

Which breeds get ectopic ureters

Answer 8

Golden retrievers, labradors, french bulldogs, poodles

Question 9

What does urethral sphincter mechanism incompetence mean

Answer 9

Weakness of the urethral muscle
- More common acquired but can be congenital

Question 10

What is spay incontinence

Answer 10

Type of urethral sphincter mechanism incompetence where there is a loss of hormonal influence (estrogen) that normally contributes to the number of alpha receptors on urethral smooth muscle ad their activity

Question 11

How can we get secondary bladder hypoplasia

Answer 11

If puppies are always incontinent can stop proper bladder development

Question 12

What s destrusor gyperexcitability

Answer 12

Urge incontinence
An acquired cause or urinary incontinence which is presumed where patients don’t improve with treatment

Question 13

What is overflow incontinence and when is it seen

Answer 13

When there is leakage down the ureathra from obstruction or malfunction of the bladder e.g in neuro conditions, bladder atony, urethral/bladder neck partial obstruction

Question 14

Acquired causes of urinary incompetence

Answer 14

USMI
OVerflow incontinence
UTI; tipping borderline incontinent patients over line
PU/PD putting lots of pressure on system
Destrusor hyperexcitability

Question 15

What is urodynamics and what is it used to

Answer 15

Catheter with pressure detectors placed in bladder and withdrawn through urethra to give urethral pressure profile

Used to diagnose USMI

Question 16

How to medically manage bladder atony/overstretching

Answer 16

Want to increase detrusor contractivity
- Via activation of parasymp system with Methanecol Chloride
–> Improves voiding efficiency

Side effects = non-specific parasympathomimetic effects: salivation, vomiting, diarrhoea, GI hypermotility

Question 17

How to medically manage urge incontinence

Answer 17

Treat any UTIs first
Then antimuscarinics e.g oxybutinin or propantheline to reduce unstable contractions and reduce detroser contratility

Side effects: decreased salivation, constipation, reduced GI motility, tachycardia

Question 18

MEdical management of USMI

Answer 18

Increase urethral resistance
- Can use alpha-adrenergic agonists to act on alpha receptors of smooth muscle; phenylpropanolamine
NB: can lead to aggression, restlessness, hypertesion (since it is a sympathomimetic)

Oestrogens use to increase sensitivity of urethral muscle to catecholamines

Question 19

Medical management of feline urethral spasm or reflex dyssynergia in dogs

Answer 19

Want to reduce urethral resistance

Smooth muscle relaxation:
- Use alpha-adrenergic blockers e.g Prazosin, Phenoxybenzamine to reduce smooth muscle tone
Side effects = hypotension since reduced symp tone

Skeletal muscle relaxants:
Dantrolene, sedatives

Question 20

Why don’t we use diazepam in cats

Answer 20

Risk of idiosyncratic hepatic necrosis

Question 21

How can we do surgery to deal with bladder atony

Answer 21

Put in. a cystostomy tube to rest the detrusor muscle to allow tight junctions to reform and recover from overstretching

Question 22

What should we do before starting urinary surgery

Answer 22

Treat concurrent UTI; otherwise tissue friable and more risk of post-op sepsis if urine leaks out
Imaging to see what stone type and where etc

Question 23

Surgical approach for cystotomy and where on the bladder do we incise

Answer 23

Caudal midline coeliotomy from caudal to umbilicus to pubis

Incise on the ventral midline to avoid the ureters

Question 24

How long does bladder take to heal after surgery

Question 25

What suture material do we use to close the bladder and which layer

Answer 25

Use monofilament, absorbable synthetic

If bladder all healthy monocryl will last long enough
If more inflamed use PDS to last a bit longer

Simple continuous pattern
Avoid penetrating the mucosa but not a big issue if do as will be covered by urothelium ; submucosa = the suture holding later

Question 26

How do we work out if it is urine which is free fluid in abdomen

Answer 26

Do an abdominocentesis and compare the K+ and creatinine level in this fluid to the blood
If it is much higher = urine

Question 27

How could a patient with uroabdomen present

Answer 27

= Depressed, tacky MMs, distended abdomen and fluid thrill, relative bradycardia

high K+, azotaemic, acidotic

Question 28

How to deal with high K+ and azotaemia before starting surgery

Answer 28

• Hartman’s bolus ; NB we choose this because combats acidosis better than saline and the small amount of K+ in hartman’s is not too significant
• Calcium gluconate to protect heart
• Drain urine using foley catheter

Then check if this worked
If it didn’t; insulin+glucose to drive K+ into cells; sodium bicarbonate

Question 29

What is a percutaenous cystolithotomy

Answer 29

Minimally invasive way to remove stones via hole in body wall and laparascopic trochar into bladder

Good magnification and illumimination so less liekly to leave stones behind
NB: can’t remove stones >2cm

Question 30

What is a partial cystectomy and when might we do it

Answer 30

REmoval of part of bladder
- With discrete neoplasia, polyps, trauma with necrosis, patent urachus/urachal diverticulum

Can remove 75% of bladder and will be fine
Must leave trigone in tact to avoid incontinence

Question 31

What are cystotomy tubes for

Answer 31

Temporary or permanent urinary diversion in cases of bladder atony, neoplasia, trauma, urethral obstruction (durng stabilisatino)

Can be surgically placed
Or percutaneous in an emergency to provide drainage

Question 32

What breed is prone to urate stones due to metabolic defect stopping urea breakdown

Answer 32

Dalmations

Question 33

Scrotal urethrostomy indications

Answer 33

Create opening proximal to the narrow penile urethra
- When stones likely to recur e.g dalmation with urate stones or have recurred

Must castrate to do this

Question 34

Indications for perineal urethrostomy

Answer 34

To remove a narrow urethral portion e.g recurrent spasm/plug causing obstruction, urethral stricture, trauma, very recurrent urolithiasis, priapism
- Dont in cats

Question 35

Treatment options for intramural ectopic ureters

Answer 35

Cystoscopic laser ablation is minimally invasive
Nephro-ureterostomy side-side
Ureteral re-implantation
Ureteronephrectomy i.e removing ureter and kidney as salvage

Question 36

Treatment options for extra-mural ureters

Answer 36

Just ureteral re-implantation or salvage ureteronephrectomy

Question 37

Surgical treatment options for USMI summary

Answer 37

Re-location of bladder neck via colposuspension or pexy procedures

Increasing urethral resistance: artificial urethral spincter or urethral bulking agents

Question 38

What is colposuspension and how is it used to treat USMI

Answer 38

Suture between vagine and body wall to move the bladder into a more intra-abdominal area
This was when the animal lies down there is the same pressure on the urethra and bladder so don’t get leakage

Commonly done in females = this or artificial sphincter

Question 39

How does an artifical urethral sphincter work

Answer 39

Place a silicone cuff around the urethra which is adjustable over time to inflate if needed
Up to 50% are continent without inflation