15) Micturition and Incontinence

Question 1

What structures of the bladder are involved in storage and micturition?

Answer 1

Detrusor muscle
Internal urethral sphincter (often only in males)
External urethral sphincter

Question 2

At what volume do we first sense there is urine in the bladder?

Answer 2

150ml

Question 3

Describe SNS activity on bladder in storage:

Answer 3

Hypogastric nerve (T10-L2) acts on beta 3 receptors in detrusor muscle to relax it

Question 4

Describe SNS activity on internal urethral sphincter in storage:

Answer 4

Hypogastric nerve (T10-L2) acts on alpha 1 receptors in internal urethral sphincter to contract it

Question 5

What does the SNS have an effect on during micturition?

Answer 5

Bladder and internal urethral sphincter to allow storage

Question 6

What acts on external urethral sphincter during storage?

Answer 6

Somatic motor neurones from pudendal nerve (S2-4) act on nAChr to cause contraction

Question 7

How do we know how full the bladder is?

Answer 7

Stretch receptors in wall which feed sensory information regarding bladder stretch back to spinal cord

Question 8

What is the L centre and what does it control?

Answer 8

Is the pontine storage centre in the brainstem and controls storage phase of micturition:
Stimulates SNS and somatic NS
Inhibits PSNS

Question 9

What does the PSNS have an effect on during micturition?

Answer 9

Pelvic nerve (S2-4) acts on M3 receptors to cause contraction of detrusor muscle

Question 10

What stimulates the M centre and PSNS?

Answer 10

Afferent impulses from bladder stretch

Question 11

What is the M centre and what does it control?

Answer 11

Pontine micturition centre in brainstem that:
Inhibits L centre -> relaxes EUS
Inhibits SNS
Stimulates PSNS

Question 12

What are the M and L centre controlled by?

Answer 12

Cortex which can override these centres

Question 13

Why can’t babies control when they micturate?

Answer 13

No descending neuronal modulation from brainstem, so automatic voiding when bladder reaches certain level

Question 14

Where is the detrusor muscle located?

Answer 14

Below the submucosa and surrounded in adventitia

Question 15

What are the muscle layers of the bladder and why are they important?

Answer 15

3: inner longitudinal, circular and outer longitudinal

Allow strength in all directions of stretch

Question 16

What is the internal urethral sphincter?

Answer 16

Continuation of detrusor muscle at bladder neck

Question 17

What is the external urethral sphincter?

Answer 17

Skeletal muscle derived from pelvic floor muscles

Question 18

What effect does a lower motor neurone (below T12) lesion have on bladder?

Answer 18

Flaccid bladder - damage to parasympathetic outflow so detrusor muscle can’t contract. Bladder fills uncontrollably until overflow incontinence

Question 19

What effect does a upper motor neurone (above T12) lesion have on bladder?

Answer 19

Reflex bladder - no afferent signals from bladder wall so no awareness of filling, micturition reflex so bladder empties as it fills. May get dyssynergia, where sphincters are poorly co-ordinated

Question 20

How would you classify lower urinary tract symptoms?

Answer 20

Problems with storage, voiding or post micturition

Question 21

How may storage problems present?

Answer 21

Frequency, urgency and nocturia

Question 22

How may voiding problems present?

Answer 22

Slow stream
Hesitancy
Straining
Terminal dribble

Question 23

How may post-micturition problems present?

Answer 23

Feeling of incomplete emptying or dribble

Question 24

What is urinary incontinence?

Answer 24

Complaint of any involuntary leakage of urine

Question 25

What is stress UI?

Answer 25

Involuntary leakage on effort or exertion, or on sneezing or coughing

Question 26

What is urge UI?

Answer 26

Involuntary leakage accompanied by or immediately proceeded by urgency

Question 27

What is mixed UI?

Answer 27

Involuntary leakage associated with urgency and exertion

Question 28

What is overflow incontinence?

Answer 28

Retention of urine causes bladder to swell until it can't hold anymore

Question 29

What is overactive bladder syndrome?

Answer 29

Encompasses both MUI and UUI, and with symptoms of urgency, frequency and nocturia

Question 30

What is the association of incontinence and age?

Answer 30

Increasing prevalence with age

Question 31

What are some risk factors for incontinence?

Answer 31

``` Weakened pelvic floor muscles (child-birth, surgery) Age Obesity UTI Menopause ```

Question 32

What examinations may you do to investigate incontinence?

Answer 32

BMI Abdominal examine to exclude palpable bladder Digital rectal examination Stress test

Question 33

What investigations may you carry out?

Answer 33

Urine dipstick Freq-vol chart Post-micturition residual volume - ultrasound Invasive urodynamics - contrast and video Cytoscopy - looking for cancer or stones

Question 34

What general management may be recommended?

Answer 34

``` Modify fluid intake Weight loss Stop smoking Decrease caffeine Fixed schedule for voiding ```

Question 35

What can be used if patients can't have surgery and conservative management hasn't worked?

Answer 35

Indwelling catheter Sheath device - condom catheter Incontinence pads

Question 36

What specific management for SUI is there?

Answer 36

Pelvic floor muscle training - 8 contractions, 3 times a day for 3 months Duloxetine - combined noradrenaline and serotonin uptake inhibitor, increases activity of EUS in filling, but many side effects

Question 37

What surgical options can be offered for females with SUI?

Answer 37

Permanent intention: Low-tension vaginal tapes - support mid-urethra Retropubic suspension procedures - corrects position of proximal urethra Classical sling procedures - supports urethra Temporary intention: Intramural bulking agents - allows urethra to resist abdominal pressure

Question 38

What surgical options can be offered for males with SUI?

Answer 38

Artificial urinary sphincter - stimulates normal sphincter to close Male sling procedure

Question 39

What specific management for UUI is there?

Answer 39

``` Bladder training Anticholinergics (M2, M3) - oxybutynin B3 agonist - mirabegron Botulinum toxin - prevents ACh release so no detrusor muscle contraction, 3-6 months Surgery - sacral nerve neuromodulation ```