MNP urinary/fecal continence Flashcards
lower urinary tract anatomy in male/female
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
storage phase
- 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
voiding phase
when critical volume of bladder has been reached
A delta afferent from mechanorecept in the bladder wall -> pelvic nerve -> spinothalamic/spinobulbar -> thalamus -> periaqueducal grey + voiding mict center (L region) ->pontine reticulospinal -> sympat, parasympat
unmyelin C fiber ->spinomesen, spinoreticular, spinohypothal
autonomic regul
+ paraventricular and periventricular nuicelus of hypothalamus, redu nucleus, raphe nulceus, cerebellum
afferent innervation of the baldder
L1-4: hypogastric nerve, pain recept
S1-3: pelvic nerve, stretch recept
pudendal nerve, recept for flow, distention, pain
efferent innervation of the bladder
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
common cause of urinary incontinence in dog
- 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
breeds overrepresented in developing USMI
german sheperd
rottweiler
doberman pinscher
giant schnauzer
old english sheepdog
boxer
english springer spaniel
weimaraner
irish setter
soft-coated wheaten terrier
pattern of urinary incontinence in female
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
pattern of urinary incontinence in male
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
post voiding resiudal volume in dog
0.2 to 1 mL/kg
Give 2 molecules to help for urine stockage and their mechanism of action.
Oxybutynin: muscarinic receptor antagonist (decrease detrusor contractility)
Phenylpropanolamine: sympathomimetic (increase internal sphincter tone)
Give 5 molecules to help for urine voiding and their mechanism of action.
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)
changes after suprasacral SC injury
C fiber activation (expression lower threshold Na channel, K channel functionnaly incapacited)
=> concurent detrusor and sphincter contraction
inneficient bladder emptying, high residual volume, detrusor hypertrophy, blader overdistention
reflex micturition is mediated by
C fibers
most prevalent uropathogen
E coli
