Incontinence Flashcards
What is the anatomy of the bladder that helps maintain continence?
maintained by the co-ordinated interaction of the bladder, urethra, pelvic floor muscles and the nervous system
The bladder is low pressure-high volume system, the pressure increases slowly as the bladder fills (rate 0.5- 5ml/hr)
Bladder capacity is approx. 600ml, with a desire to void being felt at approx. 250ml
Continence is maintained as long as the urethral pressure exceeds the bladder pressure
What does the process of micturition require?
The voluntary relaxation of the striated muscle around the urethra, this reduces urethral pressure
This is followed by a corresponding increase in bladder pressure as a consequence of detrusor contraction
How does bladder contraction occur via the parasympathetic nervous system?
The pontine micturition centre (midbrain) co-ordinates detrusor contraction with urethral relaxation
Bladder contraction is mediated by the parasympathetic system, these parasympathetic fibres, along with those responsible for somatic control (pudendal nerve), originate from the sacral plexus (S2 to S4).
Excitation of the parasympathetic nerves stimulates the release of acetylcholine, which acts on muscarinic receptors (there are 5 subsets of muscarinic receptors with subset M3 being primarily responsible for bladder contraction) to cause detrusor contraction
How is bladder filling mediated via the sympathetic nervous system?
Bladder filling is mediated by the sympathetic system, sympathetic nerves arise from T11 to L2 and innervate the smooth muscle of the bladder neck and proximal urethra causing contraction, allowing the bladder to fill
Excitation of the pudendal nerve causes contraction of the external urethral sphincter, allowing voluntary control, voiding therefore depends on parasympathetic activity, with opening of the bladder neck, which is involuntary, followed by voluntary relaxation of the external urethral sphincter
What are the types of incontinence?
Common forms: Urge incontinence Stress incontinence Mixed incontinence Functional incontinence Less common forms: Faecal Overflow Reflex Noctural eneuresis
What is stress continence?
The involuntary leakage of urine during increased abdominal pressure in the absence of detrusor muscle contraction
Urethral hypermobility, dependent on pelvic floor muscle, uretheral support
Sphincter deficiency- dependent on pudendal innervation, urethral striated and smooth muscle function
What is urge incontinence?
Overactive bladder or detrusor overactivity
syndrome consisting of urgency with or without incontinence, usually companied frequency and nocturia
Reduced bladder capacity
Patchy innervation
Balance of excitatory neurotransmitter alter
Increase in spontaneous bladder activity
Detrusor overactivity, urodynamic observation, involuntary detrusor contractions during the filling phase
What is overflow incontinence?
Urinary incontinence associated with chronic retention of urine, 2 main causes
Detrusor failure- neurological, medication induced, diabetes, spinal surgery
Obstruction- enlarged prostate, bladder stones, tumour, urethral stricture
What is functional incontinence?
When someone is not normally incontinent, but is incontinent due to external factors, often develops in hospital
Inability to communicate need to go to the toilet
Immobility
Sedation
Unfamiliar surroundings
Cognitive impairment
Clothing
How does ageing effect continence?
Reduced balder capacity Reduced blood flow Reduced totally collagen Slowing of nerve conduction time Degenerative changes to urethral support structures
What are the symptoms of incontinence?
Detrusor overactivity- the bladder contracts spontaneously during filling as the patient attempts to prevent micturition, this diagnosis can only be confirmed using urodynamics
Urge incontinence- involuntary leakage of urine accompanied or preceded by urgency, this is usually associated with detrusor instability
Urinary incontinence- the involuntary loss of urine
Hesitancy- involuntary delay or inability in starting the urinary stream
Nocturia- the need to pass urine during the night which awakens one from sleep, as well as causing problems with sleep disturbance, nocturia is also an independent risk factor for falls
What is an overactive bladder?
Syndrome including urinary urgency +/- urge incontinence, usually accompanied by urinary frequency (voiding >x8/24hr) and nocturia- can be associated with detrusor overactivity
What is nocturnal polyuria?
Passing >1/3 of your urine volume during the night, this diagnosis can be made quite easily by viewing frequency volume charts
What can incontinence result from?
Weakness of the urinary outlet, stress incontinence
Failure of the bladder to store urine because of higher bladder pressure, urge incontinence
A combination of the first 2, mixed incontinence
A bladder that is overfull and overflows, bladder outlet obstruction
Abnormal communications of the urinary tract- fistulae
Incontinence due to general impairment (cognitive, function or affective), functional
What is the aetiology of functional incontinence? (DIAPPERS)
Delirium Infection Atrophy- vaginal Pharmacology Psychological Excess urine output, polyuria Restricted mobility Stool impaction, constipation
