Urinary incontinence Flashcards
Describe how to bladder fills
The sympathetic nervous system predominates–> inhibition of detrusor muscle allows passive filling of the bladder- sympathetic nervous system also contracts the internal urethral sphincter
what is the micturition reflex
detrusor reflex and inhibition of sympathetic and somatic stimulation to bladder and ureters
describe how urination occurs
The parasympathetic nervous system dominates
When threshold is reached, stretch receptors in the bladder wall stimulate detrusor muscle contraction = detrusor reflex
Urethral sphincter muscles relax
define true urinary incontinence
the patient is unaware that they are leaking urine. Usually due to poor sphincter functionality (uncommon in cats)
define urge incontinence
the patient is aware that they need to urinate but may have lack of control. Can be caused by bladder irritation or seen as inappropriate urination
define overflow incontinence
the patient is (usually) unaware that they are urinating, occurs when urine pressure within the bladder is greater than the urethra. Considered a ‘voiding’ rather than storage disorder
describe somatic nervous control of the bladder
The somatic nervous system (voluntary):
Stimulates urethral striated muscle contraction (for sudden or prolonged increases in bladder pressure)
what other signs may you see with neurogenic incontinence
LMN signs
paralysis
what are non-neurogenic incontinence
anatomical or functional disorders of the urinary tract
what are the 2 broad categories of incontinence
neurogenic and non-neurogenic
if there is a cerebral lesions what will it present with regarding the bladder
Causes rare, loss of voluntary control
The bladder can empty normally but often at inappropriate times
List 4 things that are seen with brainstem-L7 lesions what will it present with regarding the bladder
- Bladder is hard to express
- Increased urethral sphincter tone
- High volume urinary retention
- Development of automatic bladder*
List 6 things that are seen with S1-S3 or nerve root lesion what will it present with regarding the bladder
Absent voluntary micturition
Bladder is atonic, flaccid and easy to express
Concurrent reduced perineal reflex and anal tone, may have tail paralysis
Atonic urethral sphincters
Absent detrusor reflex
Can result in overflow incontinence when full
what is the most common presentation of Urethral Sphincter Mechanism Incompetence (USMI)
female
spayed
older
large breed
overweight
what is the most common non-neurogenic cause of canine incontinence
Urethral Sphincter Mechanism Incompetence (USMI)
how do Urethral Sphincter Mechanism Incompetence (USMI) presents
as intermittent involuntary leaking of urine when dog is relaxed (sleeping) or excited
Patient may have good/bad leaking days
List the 2 problems that are occurring in Urethral Sphincter Mechanism Incompetence (USMI) that we can try and medically manage
low urethral tone/ reduce amount of smooth muscle in urethra
hormonal influence (aging or lack of oestrogens change urethral structure)
Describe how we medically manage low urethral tone/ reduce amount of smooth muscle in urethra in USMI
sympathomimetic agents= aim to mimic the storage of urine phase - e.g. phenylpropanolamine
Describe how we medically manage hormonal influence of USMI
give oestrogens (only neutered bitches) = acts on oestrogen receptors in sphincters e.g. incurin
what happens with ectopic ureters
Incontinence observed shortly after birth
Bladder is bypassed and urine may empty into vagina or urethra
describe how to treat an ectopic ureter
surgical
describe detrusor instability
an overactive bladder presenting as pollakiruria. Most animals have underlying cystitis, irritating the bladder lining and over stimulating the detrusor reflex. = URGE INCONTINENCE
list the 2 reasons that urinary retenttion occur
detrusor muscle isn’t working well
OR
bladder is contracting against high outflow pressure
what do we tend to see with urinary retention
stranguria or dysuria, and may be attempting to void urine but be unsuccessful.
describe how to manage urine retention issues
Facilitate bladder emptying
Medicate depending on cause
List 4 possible causes of neurogenic urinary retention
LMN disorder
UMN disorder
Detrusor-urethral dyssynergia
Dysautonomia- RARE- would have other neuo signs as well
List 3 possible causes of non-neurogenic retention
blockage
Trauma to ureters and/or bladder
Detrusor atony
describe detrusor atony
Often from over distention of bladder; secondary condition we want to avoid
Bladder distended and flaccid
Describe how to manage Lower Motor Neuron (LMN) disorders that affect the bladder
Bethanecol (a parasympathomimetic) may improve bladder contractility IF there is some function left
Nursing/home care: manual expression 3-4 x daily, cleaning, monitoring for UTi
Describe what can happen with upper motor neuron disorders
Disruption between the sacral segments and the pontine micturition centre in the brain
——> reflex detrusor contraction (trying to empty bladder)
—–> concurrent uninhibited sphincter spasticity (hard to empty past this)
Describe how to treat UMN disorders that are affecting the bladder
urethral smooth muscle relaxants
skeletal muscle relaxants
monitoring for UTI is important
what is Idiopathic reflex dyssynergia
Loss of coordination between the detrusor muscle contracting, and the relaxation of the urethra. (they are not working coordinated)
Presents a spurting urine flow
describe how to treat Idiopathic reflex dyssynergia
short term- treat underlying cause and prevent over distention
Help restore normal detrusor contraction (parasympathomimetic agents)
May improve spontaneously or require medication long-term
what is the most common dogs affected by Idiopathic reflex dyssynergia
male dog
large breed
