Urinary 9 - Micturition + Incontinence Flashcards
What type of muscle forms the internal urethral sphincter?
Smooth muscle
What type of muscle forms the external urethral sphincter?
Skeletal muscle
Which urethral sphincter is formed of smooth muscle?
Internal urethral sphincter
Which urethral sphincter is formed of skeletal muscle?
External urethral sphincter
Name the area of the bladder wall which doesn’t have rugae present:
Trigone
Name the 4 layers of the bladder wall:
1) Urothelium + Mucosa
2) Submucosa + Lamina propria
3) Muscular
4) Serous visceral peritoneum
What is the outermost layer of the bladder wall?
Serous visceral peritoneum
Describe the innermost layer of the bladder wall:
Urothelium (transitional epihelium) and mucosa form RUGAE
= Allows distension of bladder without increasing pressure
(Rugae not present in trigone area)
Describe the muscular layer of a bladder wall:
Detrusor muscle has 3 layers:
- Outermost = longitudinal
- Middle = circular
- Innermost = longitudinal
Why does the detrusor muscle have criss-crossed layers?
To provide strength from every direction when stretched
Which nerves innervate the external urethral sphincter, and what is their function?
Somatic Pudendal nerves (S2-4)
= Contracts external sphincter
Which nerves innervate the internal urethral sphincter, and what is their function?
Sympathetic T11-L2
= Contracts internal sphincter
What are the nerve roots of the sympathetic nerves which innervate the bladder and internal urethral sphincter?
T11 - L2
What are the nerve roots of the sensory nerves detecting bladder stretch?
S2, S3, S4 Keeps the bladder off the floor
What reaction is caused by a low sensory input from the bladder?
Sensory fibres synapse with sympathetic nerves (T11-L2),
= Relaxation of detrusor muscle and contraction of internal urethral sphincter
What reaction is caused by a high sensory input from the bladder?
Sensory nerves synapse parasympathetic fibres (S2-4)
= Contraction of detrusor muscle
Sensory nerves synapse M center, which:
Inhibits L center = Allows relaxation of internal and external sphincters
Which pontine continence center facilitates micturition?
M (medial) center
Which pontine continence center factilitates urine storage?
L (lateral) center
What type of receptors are present in the bladder wall, and respond to Ach?
M2-3
Name the 2 pontine continence centers, and their main functions:
1) L (lateral) - facilitates urine storage
2) M (medial) - facilitates micturition
At what volume of fluid in the bladder do you become aware (of fluid in the bladder)?
~ 150 ml
What structures prevent retrograde ejaculation into the bladder?
- Internal urethral sphincter
- Prostatic urethra
Define incontinence:
The complaint of any involuntary leakage of urine
List some symptoms of problems with urine storage:
- Nocturia
- Increased frequency
- Incontinence
- Urgency
List some symptoms of problems with micturition:
- Pain
- Hesitancy
- Intermittency
- Slow stream
- Spitting/spraying
- Straining
- Terminal dribble
List some symptoms of problems post-micturition:
- Post-micturition dribble
- Feeling of incomplete emptying
List some causes of temporary urinary incontinence:
- UTI
- Constipation
- Alcohol
- Caffeine
- Artificial sweeteners
- Foods high in sugar/spice/acid
List some causes of persistent urinary incontinence:
- Pregnancy
- Childbirth
- Hysterectomy
- Enlarged prostate
- Prostatic cancer
- Age
- Obstruction: Tumour/Stone
- Neurological disorder (MS, parkinson’s, stroke, tumour, spinal injury)
How would a lower motor neuron lesion (S2-4) affect micturition?
Decreased detrusor pressure = large residual urine volume = overflow incontinence
How would an upper motor neuron lesion affect micturition?
Increased contractions of detrusor causing increased detrusor pressure (poor coordination with sphincters)
= micturition as soon as urine present
Name the 4 classifications of urinary incontinence:
1) Urge incontinence
2) Overflow incontinence
3) Stress incontinence
4) Mixed incontinence
What is the most common type of incontinence (~47%)?
Stress urinary incontinence
Describe stress urinary incontinence:
Complaint of involuntary urine leakage on exertion or effort, or sneezing/coughing
Describe urge urinary incontinence:
Complaint of involuntary urine leakage, immediately preceded by urgency
Describe mixed urinary incontinence:
Complaint of involuntary urine leakage with urgency and also on effort/exertion/sneezing/coughing
Describe overflow incontinence:
Complaint of frequent involuntary urine leakage due to inability to completely empty bladder
Name the main 3 symptoms of Overactive Bladder Syndrome (OABS):
1) Nocturia
2) Increased frequency
3) Urgency
What name is given to describe the symptom of involuntary urine leakage when coughing/sneezing?
Stress urinary incontinence
What name is given to describe the symptom of involuntary urine leakage immediately preceded by urgency?
Urge urinary incontinence
What types of examination may a doctor do if patient presents with incontinence?
- BMI check
- Abdominal exam (palpate bladder)
- Digital rectal exam (Males)
- External genitalia stress test (Females)
What is most important investigation that should always be done if a patient presents with incontinence?
Urine dipstick test
= Check for UTI, haematuria, proteinuria, glucosuria
List some investigations which may be performed on a patient presenting with incontinence:
- Urine dipstick
- Non-invasive urodynamics (Freq/V chart, Bladder diary > 3 days
- Invasive urodynamics (pressure/flow studies)
- Pad tests
- Cytoscopy
Describe the initial management of a patient with stress urinary incontinence:
- Pelvic floor exercises
- Modify water intake
- Weight loss
- Stop smoking
- Decrease alcohol/caffeine intake
Describe the initial management of a patient with urge urinary incontinence:
- Bladder training (timed voiding)
- Weight loss
- Modify water intake
- Stop smoking
- Decrease alcohol/caffeine intake
If patient with incontinence has failed initial management, and is unsuitable for surgery, what are the other management options?
- Indwelling catheter
- Sheath device
- Incontinence pads
- Drugs
What drug is used to treat stress urinary incontinence, and how does it work?
Duloxetine
- Combined NA and Serotonin uptake inhibitor = increased activity in external sphincter during filling phase
What drugs are used to treat urge urinary incontinence?
1) Anticholinergics ie Oxybutynin
2) B3 adrenoceptor agonist ie Mirabegron
3) Botulinum toxin
Give an example of an anticholinergic drug used to treat urge urinary incontinence, and give the advantages and disadvantages of use:
Oxybutynin
Adv = Cheap
Disadv = Side effects: Dry mouth, nausea, increased heart rate, mental/mood changes
Give an example of a B3 adrenoceptor agonist drug used to treat urge urinary incontinence, and how it works:
Mirabegron
= Increases bladder capacity as allows bladder relaxation
How is botulinum toxin used to treat urge urinary incontinence?
Injected into detrusor muscle, inhibiting Ach release = partial paralysis, allowing bladder to fill without stimulating micturition
Lasts 3-6 months
What is the main side effect of paralysing the bladder with botulinum toxin?
Increased risk of UTIs
Give the 4 possible surgical managements for a female with stress urinary incontinence:
1) Low-tension vaginal tapes
2) Open retropubic suspension procedure
3) Classical fascial sling procedure
4) Intramural bulking agent
Which surgical management of stress urinary incontinence would allow a female to have further pregnancies? (Is temporary)
Intramural bulking agents
What is the surgical management available to men with stress urinary incontinence? How does it work?
Artificial urinary sphincter
Hydraulic cuff stimulates action of normal sphincter
Give the 4 possible surgical managements for a patient with urge urinary incontinence:
1) Sacral nerve neuromodulation
2) Autoaugmentation
3) Autoaugmentation cystoplasty
4) Urinary diversion
