Micturition Disorders Flashcards
urinary incontinence
passive leakage of urine WITHOUT voluntary control or sense of urgency
pollakiuria
passive leakage of urine WITH voluntary control or sense of urgency
ddx for urinary incontinence
storage vs voiding
storage: ectopic ureters, USMI, overactive bladder secondary to UTI/neoplasia/infection etc
voiding: urethrolith, neoplasia, proliferative urethritis, iFUOTO
ddx for pollakiuria
UTI
uroliths
neoplasia
foreign body
foreign body
polypoid cysts
sympathetic pathway on urination
stimulates passive urine retention
L1-L4 –> caudal mesenteric ganglia –> hypogastric nerve –> NE –>
- beta receptors (bladder) –> relaxation
- alpha receptors (internal urethral sphincter) –> contraction
parasympathetic pathway on urination
stimulates urine release
S1-S3 –> pelvic nerve –> acetylcholine –> muscarinic receptors in detrusor muscle –> bladder contraction
somatic pathway on urination
conscious urine retention
S2-4 –> pudendal nerve –> acetylcholine –> nicotinic receptors in external urethral sphincter –> EUS contraction
storage disorders & PVRV & ddx
ALWAYS cause urinary incontinence
causes a NORMAL post void residual volume
ddx:
- ectopic ureters
- USMI
- detrusor instability
voiding disorders & PVRV & ddx
MAY cause urinary incontinence
causes an INCREASED post void residual volume
ddx:
- functional outflow obstruction
- mechanical outflow obstruction
- atonic bladder
do storage or voiding disorders cause stranguria in additional to urinary incontinence
voiding disorders
diagnostics to perform on urinary incontinent patients
- PE - record PVRV by measuring bladder size before and after urination on US
- UA - evaluate USG to differentiate from PU/PD, if bacteriuria + pyuria –> culture
- Urine Culture - only treat positive clinical cultures; if signs don’t resolve, pursure other diagnostics
- Ultrasound - evaluate for anatomic abnormalities (ectopic ureters)
ectopic ureters
congenital abnormal insertion of the ureters into the lower urinary tract
signalment for ectopic ureters
dogs
young (>1 ur)
female > males
huskies, labs, goldens
are most ectopic ureters intra or extramural and uni or bilateral
bilateral
intramural
what is the best first line diagnostic for evaluating a urinary incontinent dog
ultrasound
if normal on US –> refer for cystoscopy
what is the gold standard diagnostic for ectopic ureters
cystoscopy
able to treat intramural ureters with laser ablation at time of diagnosis
treatment for ectopic ureters
laser ablation (intramural)
cystotomy (extramural)
urethral sphincter mechanism incompetence (USMI)
“stress” incontinence
- considered a functional storage disorder
USMI signalment
urinary incontinence in a HEALTHY dog with a normal neurologic exam
larger breeds
obese
post-spay
diagnosis of USMI
primarily made on signalment and clinical signs
rule out neurologic disorder with neuro exam
- UA and culture
- UPP (not routinely performed)
USMI treatment
medical:
1. alpha adrenergic agonists
(PPA - pheynlopropanolamine)
2. estrogen (incurin)
surgical
1. urethral bulking agents (collagen)
2. urethral occluders
alpha agonists MOA
stimulates contraction of the internal urethral sphincter by increasing NE release and decreasing NE reuptake
side effects of adrenergic agonists
SNS stimulation
- restlessness
- anxiety
- aggression
- hypertension
- tachycardia
estrogen MOA
increase receptor sensitivity to estrogen receptors in the transitional epithelium of the proximal urethra
urethral bulking agents
bovine collagen
injection of collagen into the bladder wall around the urethral sphincter to decrease lumen size
used only if failure of PPA and estrogen
urethral occluders
external mechanical occlusion around the urethra
hydraulic occluder attached to a subcutaneous port –> can inflate the occluder using the vascular port
detrusor instability
non-neurologic associated bladder hyperexcitability
idiopathic is UNCOMMON - likely has an inflammatory disease going on that causes the bladder to be overactive
DDX for OAB
- uti
- urothelial carcinoma
- prostatitis
- proliferative urethritis
- polypoid cystitis
- foreign body
treatment for TRUE idiopathic OAB
anticholinergics (antimuscarinics)
- tolterodine
- oxybutynin
must rule out all underlying causes (bacterial cystitis, stones, neoplasia, etc)
anticholinergic MOA
blocks PNS stimulation of the detrusor muscle –> prevention of contraction
types of voiding disorders
mechanical: urethroliths, neoplasia, urethritis
functional: idiopathic functional urinary outflow tract obstruction (iFUOTO)
neurologic: upper motor neuron bladder (ex. disc disease affecting the hypogastric nerve - unable to shut off the SNS when time to void –> voiding against a contracted internal urethral sphincter)
diagnostic workup of voiding disorders
- rule out mechanical obstruction: radiographs, cystourethrogram, cystoscopy, abdominal US
- rule out neurologic: neuro exam
- rule in IFUOTO - high PVRV, can do urethral pressure profile
treatments for voiding disorders
mechanical: relieve obstruction
functional: alpha antagonists (flomax)
alpha antagonists
tamsulosin (flomax)
blocks alpha adrenergic receptors in the urethral sphincter –> prevents SNS stimulation of contraction –> relieves obstructed sphincter
side effects of alpha antagonists
weakness, lethargy, hypotension
