Urinary tract disorders

Question 1

What is the anatomy and function of the bladder?

Answer 1

• The bladder has a smooth muscle wall (detrusor) stores ~500ml of urine, first urge to void is felt at 200ml- drained by the urethra (4cm long), which has a muscular wall and an external orifice in the vestibule just above the vaginal introitus
• Parasympathetic NS aids voiding- sympathetic NS prevents it -‘micturition reflex’ is controlled at the level of the pons, but the cerebral cortex modifies the reflex and can relax or contract the pelvic floor and striated muscles of the urethra

Question 2

What is continence dependent on?

Answer 2

pressure in the urethra being greater than that in the bladder
bladder pressure is influenced by detrusor pressure and intra-abdominal pressure
urethral pressure is influenced by the inherent urethral muscle tone and external pressure (pelvic floor)
• Micturition occurs when the bladder pressure exceeds the urethral pressure, this is achieved voluntarily by a simultaneous drop in urethral pressure and an increase in bladder pressure due to a detrusor muscle contraction

Question 3

What are the investigations of the urinary tract?

Answer 3

• Urine dipstick test- tests for blood, glucose, protein, leucocytes and nitrites
o Nitrites- infection, so sample should be sent for MC&S
o Glycosuria- suggests diabetes
o Haematuria- suggests bladder CA, calculi or infection
urinary diary
Postmicturition USS
Urodynamic studies and cystometry
Ultrasonography: excludes incomplete bladder emptying, checks for congenital abnormalities, calculi, tumours and detects cortical scarring of the kidneys
AXR
CT urogram- contrast allows integrity and route of the ureter to be examined
Methylene dye test- leakage from places other than the urethra can be seen eg. fistulae
Cystoscopy- excludes tumours, stones, fistulae and interstitial cystitis, but gives little indication of bladder performance

Question 4

What is cytometry?

Answer 4

necessary prior to surgery for stress incontinence or for women with overactive bladder symptoms that do not respond to medical treatment
Measure pressure in the bladder whilst it is filled and a pressrre transducer in the rectum measures abdominal pressure, so the true detrusor pressure can be calculated by subtracting the two pressures
o Leaking with coughing, but no detrusor contraction- urodynamic stress incontinence
o Involuntary detrusor activity- detrusor overactivity

Question 5

What is stress incontinence?

Answer 5

complaint of involuntary leakage of urine on effort of exertion, or on sneezing or coughing
diagnosis on urodynamic studies, but can only be confirmed after overactive bladder is excluded using cystometry
• Stress incontinence accounts for 50% of causes of incontinence in females

Question 6

What are the causes of stress incontinence?

Answer 6

o Pregnancy & vaginal delivery
o Prolonged labour & instrumental delivery
o Obesity
o Age- particularly post-menopause

Question 7

What is the conservative management for stress incontinence?

Answer 7

aimed at strengthening the pelvic floor as a 1st line treatment for at least 3 months and is taught by a physiotherapist
the strength of the pelvic floor muscle contraction should be digitally assessed before treatment
exercises should consist of at least 8 contraction, 3 times a day
vaginal ‘cones’ can be inserted into the vagina and held in position by voluntary muscle contraction, increasing sizes are used as muscle strength increases

Question 8

What is the drug management for stress incontinence?

Answer 8

duloxetine (SNRI) is the only licensed drug for the treatment of moderate-to-severe USI
it enhances urethral striated sphincter activity via a centrally mediated pathway
nausea is the most frequent reported side effect (25%), but others include dyspepsia, dry mouth, dizziness, insomnia or drowsiness

Question 9

What is the surgical management for stress incontinence?

Answer 9

1st line is ‘mid-urethral sling’ procedures with a cure rate of 90%
complications include bladder perforation, post-operative voiding difficulty, bleeding, infection, de novo detrusor overactivity and suture or mesh erosion

Question 10

What is tension free vaginal tape (TVT)?

Answer 10

a synthetic polypropylene tape is placed in a U shape under the mid-urethra via a small vaginal anterior wall incision
the tension is then adjusted to prevent leakage as the women coughs
cystourethroscopy is performed to ensure that there has been no damage to the bladder or urethra
it is minimally invasive and most women can return to normal activity within a few weeks

Question 11

What is transobturator tape?

Answer 11

similar to TVT but a different insertion technique is used
the tape is passed via the transobturator foramen, through the transobturator and puborectalis muscles
unlike TVT the retropubic space is not entered, so bladder perforation is rare

Question 12

What are injectable periurethral bulking agents?

Answer 12

have a lower immediate success rate (40-60%), cure rates are low (<20%) and there is also long-term continued decline in continence
however, the procedure has low morbidity and injections can be performed under local anaesthetic
appropriate in women who have not yet completed childbirth, in the frail elderly and when previous surgery has failed

Question 13

What is an overactive bladder?

Answer 13

defined as urgency with or without urge incontinence
usually with frequency or nocturia
• Detrusor overactivity- a urodynamic diagnosis characterised by involuntary detrusor contractions during the filling phase, which may be spontaneous or provoked by coughing

Question 14

What are the causes of an overactive bladder?

Answer 14

most commonly idiopathic
can follow operations for USI (bladder neck obstruction)
occasionally due to involuntary detrusor contractions, occurring in the presence of underlying neuropathy, such as MS or SCI

Question 15

What are the signs and symptoms of an overactive bladder?

Answer 15

o	Urgency and urge incontinence
o	Frequency
o	Nocturia
o	Stress incontinence is common
o	Leak at night or at orgasm
o	Hx of childhood enuresis is common

Question 16

What is the lifestyle management for an overactive bladder?

Answer 16

o Reduce fluid intake
o Avoid caffeinated products
o Review diuretics and anti-psychotics
• Bladder training consists of education, timed voiding with systematic delay in voiding and positive reinforcement- the patient is asked to resist the sensation of urgency and void according to a timetable
should last for at least 6 weeks, often in combination with anti-cholinergic therapy

Question 17

What is the drug management for an overactive bladder?

Answer 17

o Anti-cholinergics- suppress detrusor overactivity by blocking muscarinic receptors that mediate smooth muscle contraction, allowing the detrusor to relax side effects include a dry mouth
o Sympathomimetics (eg. Mirabegron)- association with hypertension, so BP must be measured
Oestrogens- vaginal oestrogen administration reduces symptoms of urgency, urge incontinence, frequency and nocturia in post-menopausal women
Botulinum toxin A- blocks NMJ causing affected muscle to become weak- cure or improvement rates of 60-90% at 3 weeks to 12 month follow up, with a duration of 6 months after one dose. (voiding dysfunction and urinary retention)

Question 18

What is neuromodulation and sacral nerve stimulation?

Answer 18

provides continuous stimulation of the S3 nerve root via an implanted electrical pulse generator
improve the ability to suppress detrusor contractions
treatment is appropriate for refractory detrusor overactivity and has 30-50% success rate

Question 19

What is acute urinary retention?

Answer 19

• The patient is unable to pass urine for ≥12hrs- catherisation producing as much or more urine than the normal bladder capacity
o Childbirth- particularly with an epidural
o Vuval or perineal pain- eg. herpes simplex
o Surgery
o Drugs- eg. anti-cholinergics
o Retroverted gravid uterus
o Pelvic masses
o Neurological disease- eg. MS or CVA

Question 20

What are the causes of chronic retention and urinary overflow?

Answer 20

• Causes
o Urethral obstruction
 Pelvic masses
 Incontinence surgery
o Detrusor inactivity
 Autonomic neuropathies- eg. diabetes
 Previous overdistension of bladder eg. epidural anaesthesia
• Presentation may mimic stress incontinence or urinary loss may be continuous
• Diagnosis is confirmed by ultrasound or catherisation after micturition

Question 21

What is painful bladder syndrome?

Answer 21

a condition in which the patient experiences suprapubic pain related to bladder filling
accompanied by other symptoms (frequency) in the absence of UTI or other obvious pathology

Question 22

What is interstitial cystitis?

Answer 22

confined to patients with painful bladder symptoms who have characteristic cystoscopic and histological features

Question 23

What is the treatment for interstitial cystitis?

Answer 23

o	Dietary changes
o	Bladder training
o	Tricyclic antidepressants
o	Analgesics
o	Intravesical infusion of various drugs

Question 24

What are fistulae?

Answer 24

• Abnormal connection between urinary tract and other organs
most common is vesciovaginal and urethrovaginal
common in obstructed labour (developing world) or due to surgery, radiotherapy or malignancy in the West (rare)
• Investigation is with a CT urogram or cystocopy
• Surgery is usually required- though may resolve spontaneously