Disorders of the urinary tract

Question 1

Anatomy and function of the female lower urinary tract system

Answer 1

Filling phase = adequate bladder capacity and a competent urethral sphincter

Voiding phase = detrusor contractility and co-ordinated urethral relaxation

Bladder can store 500mL of urine, first urge to void at 200mL

Urethra 4cm long and has muscular wall and an external orifice in vestibule just above the vaginal Introits

Question 2

Neural control of the bladder and urethra

Answer 2

Voiding

• parasympathetic nerves aid, sympathetic avoids
• afferent fibres respond to distension of bladder wall and pass to spinal cord, efferent to detrusor muscle and cause contraction → opening of bladder neck
• efferent sympathetic fibres to detrusor muscle inhibited
• Micturition reflex controlled at pons level, cerebral cortex modifies reflex and can relax/contract pelvic floors and the striated muscle of the urethra

Question 3

Continence

Answer 3

Urethral pressure > bladder pressure

• bladder pressure influenced by detrusor pressure and intra-abdominal pressure
• urethral pressure influenced by urethral muscle tone and pelvic floor/intra-abdominal pressure

coughing does not alter the pressure difference and does not lead to incontinence normally

Question 4

Micturition

Answer 4

Bladder pressure > urethral pressure

• achieved voluntarily y simultaneous drop in urethral pressure (partly due to pelvic floor relaxation) and an increase in bladder pressure due to detrusor muscle contraction

Question 5

Incontinence: 2 main causes

Answer 5

Uncontrolled detrusor pressure increasing bladder pressure beyond that of the normal urethra

• OAB/urinary urge incontinence is the most common cause

Increased intra-abdominal pressure transmitted to bladder but NOT urethra as upper urethra neck has slipped from the abdomen → bladder pressure raised for example, when coughing

• Urinary stress incontinence most common cause

Rarer causes → urine bypassing sphincter through fistula or urinary pressure overwhelming sphincter due to overfilling go bladder due to neurogenic causes or outlet obstruction aka ‘overflow incontinence’

Question 6

Common urinary symptoms

Answer 6

Urinary incontinence is involuntary urinary leakage, which can be divided, broadly, into stress incontinence and urge incontinence.

Daytime frequency is the number of times a woman voids during her waking hours. this should normally be between 4 and 7 voids per day. Increased daytime frequency is defined as occurring when a patient perceives that she voids too often by day.

Nocturia is waking at night one or more times to void. Up to the age of 70 years, more than a single void is considered abnormal.

Nocturnal enuresis is urinary incontinence occurring during sleep.

Urgency is the sudden compelling desire to pass urine, which is difficult to defer. Urgency is most frequently secondary to detrusor overactivity, although inflam- matory bladder conditions such as interstitial cystitis may also present with this.

Bladder pain is felt suprapubically or retropubically. typically, pain occurs with bladder filling and is relieved by emptying it. pain is indicative of an intravesical pathology, such as interstitial cystitis or malignancy, and warrants further investigation.

Urethral pain is pain felt in the urethra.

Dysuria is pain experienced in the bladder or urethra on passing urine, frequently associated with urinary tract infections.

Haematuria is the presence of blood in the urine. this can be microscopic or macroscopic (frank). It is always significant and always warrants further investigation.

Question 7

Ix of the urinary tract

Answer 7

Urine dipstick

• blood, glucose, protein leucocytes, nitrites
• nitrites = presence of infection → if +ve → M+C to confirm infection and type and abx sensitivity of organism(s)
• glycosuria = diabetes
• haematuria = bladder carcinoma or calculi

Urinary diary

• 1 week, time and volume of fluid intake and micturition → drinking habits, frequency and bladder capacity

Postmicturition US or catheterisation

• excludes chronic retention of urine

Urodynamic studies, cystometry

• prior to surgery for stress incontinence or for women with OAB sx that do not respond to medical therapy
• with or without video imaging
• measures via catheter, the pressure in bladder (vesicle pressure) whilst bladder is filled and provoked by coughing
• pressure transducer in rectum/vagina to measure abdominal pressure
• true detrusor pressure = abdominal pressure - vesicle pressure
• detrusor pressure does not normally alter with filling or provocation
• if leaking occurs with coughing in absence of detrusor contraction → urodynamic stress incontinence
• if involuntary detrusor contraction occurs → detrusor overactivity (urge)
• USI and detrusor overactivity can cause leakage with exertion, but tx different

Ultrasonography

• exclude incomplete bladder emptying, congenital abnormalities, calculi, tumours, cortical scarring of kidneys

CT urogram

• use of contrast, integrity and route of ureter examined

Methylene dye test

• blue dye instilled into bladder, leakage from other places other than the urethra i.e. fistulae can be seen

Cystoscopy

• inspection of bladder cavity useful to exclude tumours, stones, fistulae, interstitial cystitis but gives little information of bladder performance

Question 8

Cystometry results for normal bladder, urinary stress incontinence, detrusor overactivity

Answer 8

Question 8

Cystometry results for normal bladder, urinary stress incontinence, detrusor overactivity

Answer 8

Question 9

urinary stress incontinence definition

Answer 9

Urinary stress incontinence is a complaint of involuntary leakage of urine on effort or exertion, or on sneezing or coughing.

urodynamic stress incontinence (USI) when confirmed with cytometry by excluding an overactive bladder

Question 10

urinary stress incontinence: epidemiology

Answer 10

Stress incontinence accounts for almost 50% of causes of incontinence in the female and occurs to varying degrees in more than 10% of all women.

Question 11

urinary stress incontinence: aetiology

Answer 11

Pregnancy

Vaginal delivery

Prolonged labour and forceps delivery

Obesity

Age (post menopausal)

Prolapse coexists but not always related

Previous hysterectomy

Question 12

Urinary stress incontinence: mechanism of incontinence

Answer 12

the bladder neck has slipped below the pelvic floor because its supports are weak, it will not be compressed and its pressure remains unchanged (Fig. 8.4). If the rest of the urethra and the pelvic floor are unable to compensate, the bladder pres- sure exceeds urethral pressure and incontinence results

Question 13

Urinary stress incontinence: clinical features

Answer 13

History

• degree to life disruption
• stress incontinence predominated but pt also complains of frequency, urgency, urge incontinence
• patient prioritise symptoms
• FAECAL INCONTINENCE, also due to childbirth injury, may coexist

Examination

• Sims’ speculum often reveals a cystocoele or urethrocoele
• Leakage of urine with coughing may be seen
• abdomen palpated to exclude a distended bladder

Question 14

Urinary stress incontinence: mx

Answer 14

duloxetine is an SNRI (not recommended for routine use)

side effects = nausea, dyspepsia, dry mouth, dizziness, insomnia, drowsiness

Question 15

Distinction between urodynamic stress incontinence and stress incontinence

Answer 15

Urodynamic stress incontinence (USI) is a disorder diagnosed only after cystometry, of which stress incontinence is the major symptom.

• Stress incontinence is a symptom: ‘I leak when I cough’. It can be due to USI, but it may also be the result of overactive bladder or overflow incontinence.

Question 15

Distinction between urodynamic stress incontinence and stress incontinence

Answer 15

Urodynamic stress incontinence (USI) is a disorder diagnosed only after cystometry, of which stress incontinence is the major symptom.

• Stress incontinence is a symptom: ‘I leak when I cough’. It can be due to USI, but it may also be the result of overactive bladder or overflow incontinence.

Question 16

OAB sx

Answer 16

urgency, with or without urge incontinence, usually with frequency or nocturia, in the absence of proven infection. The symptom combinations are suggestive of detrusor overactivity but can be due to other forms of urinary tract dysfunction.

Question 17

OAB epidemiology

Answer 17

Overactive bladder causes 35% of cases of female incontinence.

Question 18

OAB aetiology

Answer 18

idiopathic

follow USI operations → bladder neck obstruction

involuntary detrusor contraction occurring in the presence of underlying neuropathy such as MS or SCI

Question 19

OAB mechanism of incontinence

Answer 19

The detrusor contraction is normally felt as urgency. If strong enough, it causes the bladder pressure to overcome the urethral pressure and the patient leaks: urge incontinence. This can occur spontaneously or with provocation, for example, with a rise in intra- abdominal pressure or a running tap. Coughing may therefore lead to urine loss and be confused with stress incontinence.

Question 20

OAB clinical features

Answer 20

Hx

• urgency and urge incontinence, frequency and nocturia usual
• stress continence common
• some patients leak at night or at orgasm
• hx of childhood enuresis as is feacal urgency

Examination

• normal
• incidental cystocoele may be present

Question 21

OAB mx

Answer 21

Question 21

OAB mx

Answer 21

Question 22

Causes of urgency and frequency

Answer 22

Urinary infection
Bladder pathology
pelvic mass compressing the bladder Overactive bladder
Urodynamic stress incontinence (USI)

Question 23

Causes of incnontinence

Answer 23

Question 23

Causes of incnontinence

Answer 23

Question 24

Acute urinary retention

Answer 24

Unable to pass urine for 12+ hours or catheterisation producing much or more urine than normal bladder capacity

painful except during epidural anaesthesia or failure of the afferent pathways

causes

• childbirth (esp. with epidural)
• vulval/perineal pain (e.g. herpes simplex)
• surgery
• drugs = anticholinergics
• retroverted gravid uterus
• pelvic masses
• neurological disease (e.g. MS or CVA)

tx

• catheterisation for 48 hours whilst cause is treated

Question 25

Chronic retention and urinary overflow

Answer 25

Leaking occurs because bladder overdistension even- tually causes overflow. It can be due to either urethral obstruction or detrusor inactivity.

Causes:

• pelvic masses → urethral obstruction
• incontinence surgery → urethral obstruction
• autonomic neuropathies = diabetes
• overdistension of bladder = unrecognised acute retention after epidural anaesthesia

Examination = distended non-tender bladder

Ix = confirmed by US or catheterisation after micturition

Tx = intermittent self-catheterisation commonly required

Question 26

Painful bladder syndrome (PBS) and interstitial cystitis

Answer 26

PBS = suprapubic pain related to bladder filling accompanied by sx like frequency in absence of UTI

Interstitial cystitis = painful bladder sx’s who characteristic cystoscopic and histological features

tx = dietary changes, bladder training, tricyclic antidepressants, analgesics, intravesical infusion of various drugs

Question 27

Fistulae

Answer 27

These are abnormal connections between the urinary tract and other organs (Fig. 8.5). The most common are the vesicovaginal and urethrovaginal fistulae. In the developing world, they are common as a result of obstructed labour: in the West they are rare and usually due to surgery, radiotherapy or malignancy. Investiga- tion is with a CT urogram or cystoscopy. Whilst small fistulae may resolve spontaneously, surgery is usually required, the timing depending on the site and the cause

Question 28

Urinary stress incontinence at a glance

Answer 28

Question 29

Urinary incontinence classifications

Answer 29

Question 30

Urinary incontinence PACES tips

Answer 30

Question 31

Continous dribbling incontinence? Ddx and mx

Zimbabwe

Answer 31

ddx = vasicovaginal fistulae

ix = urinary dye studies

Vesicovaginal fistulae should be suspected in patients with continuous dribbling incontinence after prolonged labour and from a country with poor obstetric services. A dye stains the urine and hence identifies the presence of a fistula.

Question 32

Give 2 examples of a muscarininc antagonist

Answer 32

oxybutinin

tolterodine

Question 33

When should you not use oxybutynin?

Answer 33

Oxybutynin should not be used in the frail elderly population due to increased risk of falls. Safer alternatives include solifenacin and tolterodine. Mirabegron, a newer drug on the market, may also be useful as it thought to have less anti-cholinergic side effects.

Question 34

Urinary incontinence SUMMARY PASSMED

Answer 34

Urinary incontinence (UI) is a common problem, affecting around 4-5% of the population. It is more common in elderly females.

Risk factors

• advancing age
• previous pregnancy and childbirth
• high body mass index
• hysterectomy
• family history

Classification

• overactive bladder (OAB)/urge incontinence: due to detrusor overactivity
• stress incontinence: leaking small amounts when coughing or laughing
• mixed incontinence: both urge and stress
• overflow incontinence: due to bladder outlet obstruction, e.g. due to prostate enlargement

Initial investigation

• bladder diaries should be completed for a minimum of 3 days
• vaginal examination to exclude pelvic organ prolapse and ability to initiate voluntary contraction of pelvic floor muscles (‘Kegel’ exercises)
• urine dipstick and culture
• urodynamic studies

Management depends on whether urge or stress UI is the predominant picture. If urge incontinence is predominant:

• bladder retraining (lasts for a minimum of 6 weeks, the idea is to gradually increase the intervals between voiding)
• bladder stabilising drugs: antimuscarinics are first-line. NICE recommend oxybutynin (immediate release), tolterodine (immediate release) or darifenacin (once daily preparation). Immediate release oxybutynin should, however, be avoided in ‘frail older women’
• mirabegron (a beta-3 agonist) may be useful if there is concern about anticholinergic side-effects in frail elderly patients

If stress incontinence is predominant:

• pelvic floor muscle training: NICE recommend at least 8 contractions performed 3 times per day for a minimum of 3 months
• surgical procedures: e.g. retropubic mid-urethral tape procedures
• duloxetine may be offered to women if they decline surgical procedures
  
  • a combined noradrenaline and serotonin reuptake inhibitor
  • mechanism of action: increased synaptic concentration of noradrenaline and serotonin within the pudendal nerve → increased stimulation of urethral striated muscles within the sphincter → enhanced

contraction