Urinary Incontinence Flashcards
What are some consequences of urinary incontinence?
- Falls (& subsequent #)
- Skin irritation
- Pressure ulcers
- Social implications
- Psychological
What is important to remember in regards to urinary incontinence in the elderly?
It is abnormal
What is the normal bladder physiology?
- Hollow bag of smooth (detrusor) muscle
- In a complex network of muscle fibres and connective tissue
- Used to store urine
- Expands without pressure rising during filling
- Capacity ̴ 500 mls (usually void at ̴ 250 mls)
- Excretes urine via urethra
- Supported and maintained in the correct position by the pelvic floor muscles
Outline the anatomy of the urethra and sphincters
- Urethra exits bladder at the trigone
- Supporting structures important to maintain continence
- Forms a fibromuscular tube
- Lined by mucosa
- With submucosal vessels & connective tissue
- Urethral lumen surrounded by several muscle layers
- Outer striated sphincter (rhabdosphincter)
- Middle circular smooth muscle (thin layer)
- Inner longitudinal smooth muscle
- Smooth sphincter – Bladder neck & proximal urethra – involuntary control
- Maintained closed during storage phase
- Extends almost the length of urethra
- Striated sphincter – Intra & Extra mural components – voluntary control
- Extramural is part of pelvic floor musculature
What is the peripheral innervation of the LUT?
1. Sympathetic:
• T10–L2 (hypogastric nerve)
- Smooth muscle contraction
- Urethra and bladder base
- α receptors dominant
- *• Detrusor muscle relaxation**
- Bladder body
- β3 receptors in detrusor
- *• Inhibition of detrusor contraction**
- Action on parasympathetic ganglia
-
Parasympathetic:
• S2–S4 (“Spinal micturition centre”)
• Fibres travel in pelvic nerves
• Detrusor muscle contraction
• M3 muscarinic receptors
3. Somatic:
• Sensory
- Stretch, pain & temperature
- From bladder to spinal cord
• Motor
- Pudendal nerve
- Innervation of levator ani
- Contraction of external urethral sphincter
- Nicotinic receptors
What is the central innervation of the LUT?
• Pontine Micturition Centre:
- Brainstem
- Under control of the brain centres
- Switches between storage and micturition
modes
• Brain Centres
- Conscious & unconscious control of PMC
- Inhibitory influences from prefrontal cortex &
hypothalamus
- Critical in delaying voiding
Outline the filling/storage phase of micturition
• Primarily passive
- Requires inhibition of parasympathetic excitatory input
- Dependant on elastic and viscoelastic properties
- Needs suitable outlet resistance
- Needs low bladder muscle tension
• Increased sensory signals to cerebral cortex
• Inhibitory signals from higher centres prevent premature emptying
Outline the voiding stage of micturition
- Voluntary or involuntary
- Higher centres send ‘activating message’ downward
• INHIBITION:
- Somatic & Sympathetic reflexes
- Outlet relaxes
• ACTIVATION:
- Parasympathetic pathways
- Detrusor contracts
*Inhibition and activation must be coordinated
- Pressure rises & urine is expelled
Outline the ageing LUT bladder
- Reduced capacity
- Reduced contractility
- Increased post void volume (> 100 ml – no consensus)
- Increased uninhibited bladder contractions
- Increased incidence of bacteriuria
- Increased volume excreted later in day/night
Outline the ageing LUT urethra and pelvic floor
1. Pelvic floor muscles:
- Muscle atrophy & thinning (reduced sphincter strength/reduced ability to delay void)
- Pelvic floor organ prolapse more likely
- 2. Urethra/Vagina/Prostate:
• Reduced urethral maximal closure pressure
• Reduced vascularity, moisture & collagen
• Reduced oestrogen-collagen effect &
sclerotic change (atrophic vaginitis, storage symptoms &
incontinence)
• Increased prostate mass (overflow)
How is urinary incontinence classified?
- Stress incontinence
- Urge incontinence (over active bladder syndrome)
- Reflex incontinence
- Overflow incontinence
- Functional incontinence
- Mixed incontinence
- Transient or established
Outline the causes of transient urinary incontinence (DIAPPERS mnemonic)
- Delirium
- Infection
- Atrophic urethritis/vaginitis
- Pharmaceutical
- Psychological
- Excessive urinary output
- Reduced mobility
- Stool impaction
Outline urge incontinence/OAB syndrome
- Most common cause of incontinence in older people
- Urgency that occurs with or without incontinence
- Impaired inhibition of bladder contraction
- Bladder contracts precipitantly (urinary leakage)
- Neurological lesion: Detrusor hyper-reflexia
- No neuro lesion: Detrusor instability
What symptoms are seen in urge incontinence?
- Sudden strong desire to void
- Urgency/precipitancy (sudden, compelling, difficult-to-defer desire to pass urine)
- Generally unable to overcome
- Often have nocturia
- May have frequent, periodic incontinent episodes (OAB ‘wet’)
- May not be incontinent (OAB ‘dry’)
*New OAB symptoms require investigation
What may urge incontinence be co-morbid with?
- UTI
- Stones
- Malignancy
- Outflow obstruction (50–75% of enlarged prostates - symptoms resolve in 2/3 after obstruction relieved)
