Disorders of the urinary tract

Question 1

Urination is dependent on what things relaxing and contracting?

Answer 1

Detrusor muscle contracting

Urethral sphincter relaxing

Question 2

At what level is the micturition reflex controlled?

Answer 2

Pons

Question 3

What 2 pressures determine continence?

Answer 3

Urethral pressure (being stronger) 
Bladder pressure (intra-abdominal and detrusor)

Question 4

What are the 2 main causes of female incontinence?

Answer 4

1. Uncontrolled increases in detrusor pressure.
2. Increased intra-adbominal pressure (normally it is transmitted to the bladder and top of urethra so there is no micturition on coughing, but if it has slipped down then stress incontinence occurs and the bladder pressure increases without the urethral pressure increasing when coughing).

Question 5

Where is bladder pain and what can be the cause?

Answer 5

Bladder pain is felt suprapubically or retropublically.

Pain is indicative of an intravesical pathology, such as interstitial cystitis or malignancy.

Question 6

What dipstick test suggests an infection?

Answer 6

Positive nitrites

Question 7

What does haematuria suggest?

Answer 7

Calculi or carcinoma

Question 8

What test excludes chronic retention of urine?

Answer 8

Postmicturition ultrasound or catheterisation

Question 9

How do you differentiate urodynamic stress incontinence and detrusor overactivity?

Answer 9

Cystometry.

Cystometry directly measures, using a catheter, the pressure in the bladder (vesicle pressure) whilst the bladder is filled up and provoked with coughing. A pressure transducer is also placed in the rectum or vagina to measure abdominal pressure.

The true detrusor pressure is the vesicle pressure minus the abdominal pressure. The detrusor pressure does not normally alter with filling or provocation.

If leaking occurs with coughing in the absence of detrusor contraction then the problem is urodynamic stress incontinence. If there is an involuntary contraction of the detrusor muscle then detrusor overactivity is diagnosed.

Question 10

What is cystoscopy and what is it used for?

Answer 10

Inspection of the bladder cavity - used to exclude tumours, stones, fistulae and interstitial cystitis.

Question 11

What do you have to exclude before diagnosing urodynamic stress incontinence?

Answer 11

Overactive bladder using cystometry.

Question 12

What are the causes of stress incontinence?

Answer 12

Pregnancy and vaginal delivery
Prolonged labour
Forceps delivery 
Obesity 
Age (particularly post-menopausal)
Previous surgery
Prolapse may co-exist.

Question 13

What is the mechanism of stress incontinence?

Answer 13

Raised intra-abdominal pressure (stress) compresses the bladder and its pressure rises. In normal women, the neck of the bladder and upper urethra is also compressed by the raised pressure. However in some women the neck of the bladder has slipped below the pelvic floor because its supports are weak, so the pressure will not be changed. If the rest of the urethra and the pelvic floor are unable to compensate, the bladder pressure exceeds the urethral pressure and incontinence results.

Question 14

What conservative management is used for urodynamic stress incontinence?

Answer 14

Weight loss if obese
Addressing any causes of chronic cough (smoking)
Reduce excessive fluid intake
Pelvic floor muscle training
Vaginal cones - held in position by voluntary muscle contracting

Question 15

What drug is licensed for urodynamic stress incontinence?

Answer 15

Duloxetine - SNRI for moderate to severe USI.
It enhanced the urethral striated sphincter activity via a centrally mediated pathway.
Due to side effects it is not recommended by NICE for routine use.

Question 16

What is the surgical intervention for urodynamic stress incontinence and what are its indications?

Answer 16

Mid-urethral sling procedures are used. Either tension-free vaginal tape (TVT) or trans-obturator tape (TOT).
Surgery is considered when conservative measures have failed and the woman’s quality of life is compromised.

Question 17

What is the definition of an overactive bladder?

Answer 17

Urgency, with or without urge incontinence, usually with frequency or nocturia, in the absence of proven infection..

Question 18

What is detrusor overactivity?

Answer 18

Diagnosis characterised by involuntary detrusor contractions during the filling phase which may be spontaneous or provoked by, for instance, coughing.

Question 19

What is the conservative management of overactive bladder?

Answer 19

Reducing fluid intake or avoiding caffeine intake.
Usage of diuretics and antipsychotics should be reviewed.
Bladder training where there is timed voiding and positive reinforcement. She should resist the sensation of urgency and void according to a timetable.

Question 20

What drugs manage overactive bladder?

Answer 20

Anticholinergics - suppress detrusor overactivity. Side effects of a dry mouth.
Sympathomimetics (e.g. Mirabegron) are considered if anticholinergics are poorly tolerated. Associated with hypertension.
Oestrogens - many women develop bladder-filling symptoms after menopause and vaginal oestrogens can help.
Botulinum toxin A - blocks neuromuscular transmission, causing the affected muscle to become weak - injected cystoscopically.

Question 21

How can neuromodulation and sacral nerve stimulation help overactive bladder?

Answer 21

Continuous stimulation of the S3 nerve route via an implanted electrical pulse generator improves the ability to suppress detrusor contractions.

Question 22

What is acute urinary retention and how is it treated?

Answer 22

It is not voiding for 12 hours or more with catheterisation producing as much, if not more, urine as the normal bladder capacity.
Treated with catheterisation for 48 hours whilst the cause is treated.

Question 23

What are the causes of acute urinary retention?

Answer 23

Anticholinergics
Childbirth (particularly when treated with epidural)
Vulval or perineal pain
Surgery 
Retrograde uterus
Pelvic mass
Neurological disease

Question 24

What is chronic retention and urinary overflow? What causes it?

Answer 24

Leaking that occurs because of bladder over-distension and overflow.
This is caused by urethral obstruction or detrusor inactivity.
Urethral obstruction - pelvic masses or surgery.
Detrusor inactivity - autonomic neuropathies and previous over-distention of the bladder.

Question 25

What is the treatment of chronic retention?

Answer 25

Intermittent self-catheterisation

Question 26

What is painful bladder syndrome?

Answer 26

When patients experience suprapubic pain related to bladder filling, in the absence of UTI or other pathology.

Question 27

What are the causes of vesicovaginal and urethrovaginal fistulae?

Answer 27

Obstructed labour
Malignancy
Surgery
Radiotherapy