Session 8

Question 1

How is bladder filling detected by the nervous system?

Answer 1

Stretch receptors in the bladder wall sense increased pressure on the bladder wall due to filling and send signals down sensory nerves to the spinal cord at S2-S4 and the nerves terminate at T10-L2.

Question 2

Briefly describe the storage phase of the bladder.

Answer 2

Urine enters the bladder and pressure doesn’t initially rise due to receptive relaxation of the detrusor muscle. Bladder starts to signal that it is filling with urine at around 150ml, as it fills the pressure in the bladder begins to increase steadily and the person begins to need the toilet. Bladder becomes full at around 500ml, urination will occur between 150ml and 500ml.

Question 3

Briefly describe the voiding phase of the bladder.

Answer 3

Pressure fluctuates during voiding because of rhythmic bladder contractions until the bladder is empty.

Question 4

What is the role of the internal urethral sphincter?

Answer 4

Involved in continence and prevents retrograde ejeculation in men but not really present in women.

Question 5

What is the role of the external urethral sphincter?

Answer 5

Role in continence (pelvic floor muscles), especially in women due to the lack of IUS.

Question 6

What type of stimulation in sensory bladder neurones activates sympathetic neurones?

Answer 6

Low levels of stimulation.

Question 7

What does low sensory stimulation cause in the bladder?

Answer 7

Sympathetic nerves are stimulated which cause detrusor muscle inhibition and IUS contraction. Allows bladder filling to occur.

Question 8

What is the role of the L centre of the brainstem in micturition?

Answer 8

Causes descending modulation to allow conscious control of urination: stimulates the somatic motor neurones which control the EUS, causing contraction of the EUS and preventing urination. L centre is inhibited by M centre activity.

Question 9

What type of sensory stimulation activates parasympathetic nerves to the bladder?

Answer 9

High levels of stimulation.

Question 10

What results from high levels of sensory nerve stimulation from the bladder?

Answer 10

Parasympathetic neurones are activated which stimulate bladder detrusor muscle contraction. High levels of stimulation also activate the M centre of the brainstem, leading to increased parasympathetic stimulation and inhibition of the L centre to inhibit the storage reflex of the bladder. Allows bladder voiding.

Question 11

Where is the sensory-parasympathetic nerve synapse from the bladder voiding reflex found?

Answer 11

Between S2 and S4 in the spina cord.

Question 12

Where is the sensory-sympathetic synapse from the bladder filling reflex found?

Answer 12

Between T10 and L2 in the spinal cord (sensory fibres enter the cord between S2 and S4).

Question 13

Describe the role of the M centre of the brainstem in micturition.

Answer 13

High levels of sensory stimulation activate the M centre which causes increased parasympathetic stimulation; inhibition of the L centre and sympathetic inhibition. The cortex of the brain can cause stimulation or inhibition of the M centre to cause conscious control of micturition.

Question 14

Where does the main neurological supply to the bladder originate?

Answer 14

From the spine via cauda equina.

Question 15

Through which nerves is parasympathetic control to the bladder transmitted and what are their roots?

Answer 15

Pelvic nerves, roots S2,3,4.

Question 16

Through which nerves is somatic control to the bladder transmitted, what are their roots?

Answer 16

Pudental nerve, roots S2,3,4.

Question 17

What comprises the pelvic floor muscles, what are their innervations?

Answer 17

Levator and, innervation from pudental nerve S2,3,4; coccygeus muscle, innervation from anterior rami of S4 and S5; fascia covering the muscles.

Question 18

What are the implications of a lower motor neurone lesion on the urinary system?

Answer 18

Loss of detrusor muscle stimulation so no contraction, leads to large amounts of residual urine so may cause overflow incontinence. May also have no sensation of bladder filling and a lax anal tone.

Question 19

What are the implications of an upper motor neurone lesion on the urinary system?

Answer 19

No voluntary control to bladder so detrusor will constantly contract due to involuntary reflexes which may cause thickening of the detrusor; ureters dilate and sphincters contract most of the time, causing poor coordination; may result in urinary retention which can cause kidney damage because of the excess urine.

Question 20

What are the typical symptoms of urinary incontinence?

Answer 20

Increased frequency or urgency to urinate; nocturia; incontinence; slow stream, spitting or spraying of urine; terminal dribble; intermittency, hesitancy or straining when urinating; post-micturition dribble; feeling of incomplete emptying of the bladder.

Question 21

Define urinary incontinence.

Answer 21

Any involuntary leakage of urine.

Question 22

What is stress urinary incontinence?

Answer 22

Involuntary leakage on effort or exertion.

Question 23

What commonly causes stress urinary incontinence?

Answer 23

Increased stress on the bladder; weakened sphincter muscles; weakened pelvic floor muscles.

Question 24

What is urge urinary incontinence?

Answer 24

Incontinence caused by increased sensitivity of the detrusor muscle or bladder. Involuntary leakage is immediately preceded by urgency.

Question 25

What is mixed urinary incontinence?

Answer 25

A combination of stress and urge incontinence.

Question 26

What is overflow incontinence?

Answer 26

Involuntary leakage because the bladder is too full.

Question 27

What type of incontinence can detrusor muscle fibrosis cause and why?

Answer 27

Overflow incontinence because the bladder is unable to distend so will fill more quickly.

Question 28

What are the symptoms of overactive bladder syndrome?

Answer 28

Increased frequency or urgency to urinate; nocturia; may also have urge or mixed urinary incontinence.

Question 29

Why is urge urinary incontinence less prevalent than overactive bladder syndrome?

Answer 29

All urge incontinence is classed as a type of overactive bladder syndrome.

Question 30

What type of urinary incontinence is most common?

Answer 30

Stress, due to weakened pelvic floor muscles.

Question 31

What examinations are performed when investigating urinary incontinence?

Answer 31

BMI; abdo exam incase bladder is palpable; DRE in men; stress test and vaginal exam in women; basic neuro exam; external genitalia exam.

Question 32

What investigations are performed when investigating urinary incontinence?

Answer 32

Always do a dipstick (for UTI, haematuria, proteinuria and glucosuria); non-invasive urodynamics; may also do invasive urodynamics, pad tests or a cystoscopy.

Question 33

How is urinary in continence managed initially?

Answer 33

Initially conservatively using weight loss, changes in fluid intake, stopping smoking, lowering caffeine intake, avoiding constipation and timed voiding.

Question 34

How can urinary incontinence be managed if patients are unsuitable for surgery and have failed conservative/medical management?

Answer 34

By containing the incontinence using an indwelling urethral or suprapubic or indwelling catheter, a sheath device or incontinence pads.

Question 35

How is stress urinary incontinence managed specifically?

Answer 35

Pelvic floor muscle training; surgery to fit synthetic tapes in women and a male sling or artificial urinary sphincter in men; intramural bulking agents to increase urethral resistance; duloxetine to increase sphincter contraction using NA and a serotonin uptake inhibitor (not recommended by NICE).

Question 36

How can urge urinary incontinence be managed pharmacologically?

Answer 36

Anticholinergics to act on M2 and M3 receptors but may have (oxybutynin is recommended); beta-3 adrenoceptor agonists to increase bladder capacity by relaxing the detrusor muscle; regular botox injections to inhibit ACh release.

Question 37

How can urge urinary incontinence be managed surgically?

Answer 37

Sacral nerve neuromodulation to interrupt signals from the brain to the bladder; auto augmentation to remove the bladder; augmentation cystoplasty to enlarge the bladder; urinary diversion to divert urine around the bladder.

Question 38

How can bladder training help sufferers of urge urinary incontinence?

Answer 38

Scheduled voiding helps to increase the size of the bladder and reduce sensitivity so symptoms will become less severe.