MNP urinary/fecal continence

Question 1

lower urinary tract anatomy in male/female

Answer 1

interwoven layers of smooth muscles = detrusor accompanied by mucosal/submucosal/serosal layers.

uretral: outer layer of striated muscle, inner layer of smooth

• female: smooth m uniformly throughout the lenght of the urethra. at the external urethral orificel, striated m enclose all but the dorsal surf of the uretral . Regardless to neuter status female have higher prop of collagen lower m
• male: smooth m limited to prostatic and cranial half of membranous urethra, ticker than female. external striated m 50-70% of urethral wall, circular orientation

Question 2

storage phase

Answer 2

• low-level bladder distension: afferent signal (increase in strenght) conducted in pelvic nerve to neurons in periaqueducal grey
• pontine urine storage center (L region): excitatory connection with nicotinic cholinergic motor neuron of Onuf’s nucleus ->pudendal nerve -> external urethral sphincter
• intermedio-lateral column L1-L4 (dog) -> splanchnic nerves -> synapse with nicotin cholinergic recept on cell bodies of mesenteric ganglion or within bladder wall -> hypogastric nerve -> pelvic plexus -> inhib beta-3adrenergic recep of detrusor, excit alpha-1A adrenergic of bladder trigone

Question 3

voiding phase

Answer 3

when critical volume of bladder has been reached

A delta afferent from mechanorecept in the bladder wall -> pelvic nerve -> periaqueducal grey

M region of pontine mict center -> sacral spinal nuclei -> pelvic nerve -> pelvic plexus -> synapse in pelvic plex ganglion or bladder wall -> M3 recept in body and neck of the bladder ->detrusor contraction and uret relax

Question 4

afferent innervation of the baldder

Answer 4

L1-4: hypogastric nerve, pain recept
S1-3: pelvic nerve, stretch recept
pudendal nerve, recept for flow, distention, pain

Question 5

efferent innervation of the bladder

Answer 5

L1-4: sympathetic (caudal mesenteric ganglia, hypogastric) beta3 adren (-) within bladder wall, alpha 1A adren (+) bladder trigone (smooth m)
S1-3: parasymp (pelvic nerve and ganglia) Ach-m in bladder wall
somatic (pudendal) Ach-n in striated m spincter

Question 6

common cause of urinary incontinence in dog

Answer 6

• storage disorder (normal postvoiding residual volume):
  1. Non neurogenic: urethral spincter mechanism incompetence , urinary tract infection, blader fibrosis/hypoplasia, detrusor instability, ectopic ureters, fistulae, pelvic bladder, short or dilated urethra, vesicourethral diverticula
  2. Neurogenic: dysautonomia, disorder of sacrocaudal SC/ of cauda equina
• voiding disorder:
  1. Non neurogenic: fonctional outflow obstruction atonic bladder, bladder fibrosis, idiopathic functional outflow obstruction), mechanical outflow obstruction, (bladder torsion, foreign object, blood clot, neoplasia, proliferative urethritis, fibroepithelial polyps, prostatic disease, uroliths…)
  2. Neurogenic: cranial to S1, to sacrocaudal SC or nerve root

Question 7

breeds overrepresented in developing USMI

Answer 7

german sheperd
rottweiler
doberman pinscher
giant schnauzer
old english sheepdog
boxer
english springer spaniel
weimaraner
irish setter
soft-coated wheaten terrier

Question 8

pattern of urinary incontinence in female

Answer 8

1/ urgency or incont after voiding: detrusor instability (rule out UTI and other lower urinary tract disease, cystoscopy) -> oxybutynin (antimuscarinic)

2/ incontinence more severe at rest: urethral sphiincter mechanism incompetence (abd US, cystoscopy) ->alpha agonist (phenylopropanolamine) or estrogen (estriol)

3/ incont at rest or during normal activ: ectopic ureters (US or CT) ->surgical

Question 9

pattern of urinary incontinence in male

Answer 9

1/ weak or interrupted urine stream: voiding disorder and overflow incont (fonctional overflow obst) (rule out MOO, cytourethrogram, cystoscopy) ->alpha antagonist +/- sq m relaxant

2/ incont at rest and during normal act
- urethral sphincter mechanism incomp (cystoscopy) -> alpha ago (phenylpropanolamine) or testosterone
- ectopic ureters (us or ct) -> EU ablation

Question 10

post voiding resiudal volume in dog

Answer 10

0.2 to 1 mL/kg

Question 11

Give 2 molecules to help for urine stockage and their mechanism of action.

Answer 11

Oxybutynin: muscarinic receptor antagonist (decrease detrusor contractility)

Phenylpropanolamine: sympathomimetic (increase internal sphincter tone)

Question 12

Give 5 molecules to help for urine voiding and their mechanism of action.

Answer 12

Betanechol: parasympathomimetic (increase detrusor contractility)
Alfuzosin, prazosin, phenoxybenzamine: alpha-1 blockers (decrease internal sphincter tone)
Dantrolene: calcium release inhibitor in muscle (myorelaxant -> decrease external sphincter resistance)