Retention of
urine
Retention of urine is either acute or chronic,
the latter leading ultimately to retention-with-overflow (see Chapter 66 on
‘The prostate and seminal vesicles’).
Acute retention
•
In the male:
— Bladder
outlet obstruction
— Urethral
stricture
— Postoperative
•
In the female:
— Retroverted
gravid uterus
— Multiple
sclerosis
•
In the male child:
— Meatal ulcer
with scabbing
•
Other causes:
— Spinal anaesthesia
— Acute urethritis or
prostatitis
— Blood clot in the bladder
— Urethral
calculus
— Rupture of
the urethra
— Phimosis
— Neurogenic
(injury or disease of the spinal cord)
— Smooth muscle
cell dysfunction associated with ageing
— Faecal impaction
— Anal pain (haemorrhoidectomy)
— Intensive
postoperative analgesic treatment
— Certain drugs
Clinical
features
Clinical features of acute retention urine
•
No urine passed for several hours
•
The bladder may be visible and is tender to palpation (Fig.
65.8) and
dull to percussion
•
Rarely, a prolapsed lumbar disc causing a cauda equina lesion will be the
cause — exclude this by checking the reflexes in the lower limb and perianal
sensation
Treatment
In most patients, the correct treatment is to
pass a fine urethral catheter (14 FG — French guage is defined as the
circumference in millimetres) and to arrange further urological management.
Occasionally, a patient with postoperative retention may pass urine if he or she
is sedated and placed in a warm bath. If the patient gives a good history of
bladder outflow obstruction there seems little point in attempting conservative
measures and a catheter should be passed; this should be carried out using full
aseptic technique. Following a thorough wash of the hands and arms, sterile
gloves should be donned. The external genitalia are gently cleaned using soapy
antiseptic solution (Savlon®). A tube of local anaesthetic (Lidothesin®) is
then carefully inserted down the urethra (Figs. 65.9,65.10
,65.11 and 65.12) warning the
patient that this will create a stinging sensation, but if the jelly is injected
slowly through the plastic nozzle it should cause no pain. The jelly should be
massaged well posteriorly in the urethra in an attempt to anaesthetise the
sphincter and prostatic urethra, and it is of advantage to place a penile clamp
for 10 minutes. A small (12—14 FG) Foley self-retaining catheter should then
gently be passed down the urethra while the penis is held taut. In a female
patient, the labia should be parted using the middle and index finger of the
left hand, which should not be moved once the cleaning process has been performed
to prevent contamination. Providing a stricture is not the cause of the
retention, the catheter should normally pass freely into the bladder. Once urine
begins to drain down the catheter it is wise to pass a few more centimetres of
catheter into the bladder before the self-retaining balloon is inflated to avoid
inflation of the balloon in the prostatic urethra. Force
should not be necessary. Occasionally, a large obstructing middle lobe of
the prostate may prevent a simple catheter entering the bladder; in this
instance a coudé catheter should pass without difficulty. The bladder is then
allowed to drain and the catheter attached to a closed drainage system. In the
male, if the catheter will not pass into the bladder, it is usually due to poor
technique, lack of anaesthesia, traumatisation of the urethra or because there
is a urethral stricture. The usual reason is that the local anaesthetic has not
been left long enough.
If, after a reasonable attempt with catheters, the bladder has not been entered, the following plan should be pursued according to circumstances.
Suprapubic
puncture. Suprapubic puncture with commercially available catheters such as
Cystofix® or a ‘Bonnano’ catheter is straightforward provided that the
bladder is palpable. If such devices are not available a lumbar puncture
needle or an Abbocath® is a useful method of relieving acute retention when
catheterisation has failed. However, if the bladder is allowed to refill after
it has been punctured, leakage into the prevesical space may follow
The
best plan is to place a suprapubic catheter after anaesthetising the skin, the
fascia and the retro pubic space with 0.5 per cent lignocaine. Correct placement
of the needle can be confirmed by aspiration of the bladder. A large-bore needle
is then placed, down which a fine catheter is passed (Cystofix) and secured in
position by suturing. The other option is to place a plastic suprapubic trochar
and cannula which has a removable plastic strip on the side so that a standard
12 FG Foley catheter can be passed down it, the balloon inflated, the strip
pulled off and the plastic cannula pulled away from the catheter (Addacath).
If
these devices are not available, a catheter can be placed in the bladder under
direct vision through a small incision under local anaesthetic, although this
has nothing to recommend it if percutaneous devices are available.
Urethral
instrumentation. In a patient with a known urethral stricture, an experienced
urologist may elect to dilate the stricture or the patient may be taken to
theatre, a urethroscopy carried out, the stricture divided using a urethrotome
under direct vision and a urethral catheter placed (see Chapter 66).
Whenever the bladder is catheterised for urinary retention it is
important to record the volume drained and to examine the patient’s abdomen a
few minutes after the procedure to exclude some other intra-abdominal pathology.
Conditions such as rupture of an aortic aneurism, ureteric colic or inflamed
colonic diverticula can cause confusion as they present with a low urine
output (mistaken as retention) and abdominal pain.
Chronic
retention
Chronic
retention
• Chronic retention differs from
acute retention in that the distension of the bladder is almost painless
• These patients are at risk of
upper tract dilatation because of the high intravesical tension due to the large
residual urine and the high resting bladder pressure
• Men with chronic retention
owing to bladder outlet obstruction require urgent referral for prostatectomy
• Those with a serum creatinine
level greater than 200 micro-mol/litre are at risk of developing a postobstructive
diuresis following catheterisation and may need careful monitoring with
replacement of inappropriate urine losses by intravenous saline; they are also
at risk of haematuria as the previously distended urinary tract suddenly
shrinks. Slow decompression by means of intermittent spigotting of the catheter
does not prevent haematoma
Retention with
overflow
In this condition the patient has no control
of his or her urine, small amounts passing involuntarily from time to time from
a distended bladder. It may follow a neglected acute retention or chronic
retention.
Retention
with overflow is referred to also under ‘incontinence’ and ‘prostatic
enlargement’. The general principles which govern the treatment of this
condition are similar to those of acute retention.
IndwelIing catheters and closed systems of catheter drainage
The incidence of ascending infection following
catheterisation is decreased by connecting the catheter (urethral, suprapubic or
perineal) to sterile tubing connected to a sterile collecting bag and employing
irrigations only if clot retention occurs (Fig. 65.13). When a catheter has been
in situ for 5
days or more some degree of urethritis and bacteriuria is likely. Changing a
catheter in the presence of active urethritis entails a risk of severe infection
spreading from the anterior to the posterior urethra and thence to other parts
of the urogenital system — not to mention the risk of bacteraemia,
Special forms
of retention of urine
Postoperative
retention of urine
Retention of urine can occur after any
operation, but is common after operations on the anal canal and perineal
region. After operations on the pelvic viscera, retention of urine is so common
(sometimes owing to damage to the pelvic autonomic plexus or to nonspecific
causes) that it is usual to forestall it by inserting a catheter before or at
the conclusion of the operation.
When
the patient is an elderly male, prostatic obstruction, hitherto latent, should
be suspected. Many patients cannot urinate while lying or sitting in bed. In a
heavily sedated patient, urinary retention may be missed and patients may suffer
from severe over-distension of the bladder which can result in long-term
impairment of voiding function. This is particularly common after hip
replacement in elderly patients as there may be reluctance to catheterize them.
Treatment.
First of all, reassure the patient and provide privacy. If the male patient,
while supported, is permitted to sit on the edge of his bed he is often able to
empty his bladder. The sound of running water is often helpful. When
circumstances permit, a warm bath is often helpful. If after a reasonable trial
patients cannot pass urine they must be catheterised temporarily.
Acute retention
due to drugs
A number of drugs is prone to induce or precipitate retention of urine. Antihistamine drugs, antihypertensive drugs, anticholinergics and tricyclic antidepressants may be responsible for producing acute retention of urine.
Management
of the neuropathic bladder
Immediately after a spinal cord injury, spinal
shock occurs (see Chapter 33 on ‘The spine’), which may last for days,
weeks or even months, and in this state the detrusor is paralysed, the bladder
distends and overflow incontinence will occur. This will lead to damage to the
detrusor muscle, infection and ultimately renal failure. Management is as
follows.
2. The upper level of the neurological lesion must be assessed by the level
of sensory and motor loss. Ischaemic necrosis of the cord may extend a variable
distance below the upper level of cord injury. Where sensory loss below the
upper level of cord injury is total, recovery is unlikely. Incomplete lesions,
in contrast, may recovery somatic and bladder function.
3.
Demonstration of intact bulbocavernosus and anal reflexes indicates that
the sacral cord and nerves are intact. In such circumstances reflex bladder
contractions are likely to develop, although they may be insufficient to empty
the bladder completely. If these reflexes are absent and there is persistent
total loss of perineal sensation it means that either the sacral cord or cauda
equina is damaged. In such circumstances an acontractile bladder is likely to
develop. In cauda equina lesions there may be sensory, motor or mixed loss.
4.
Full urodynamic assessment of bladder function should be undertaken when
the injury is stable (see below). A urodynamic
study allows accurate assessment of detrusor and sphincter activity, and the
sensation. Various aspects of bladder function can be checked including adequacy of bladder emptying, bladder capacity, pressure during filling and
continence related to the extent and
level of neurological damage. Many types of bladder dysfunction can occur.
Lesions above
cord segment T1O
The common situation is an upper motor neuron
bladder with all reflexes intact but isolated from higher control and
inhibition. Such patients are at risk of autonomic dysreflexia.
Emptying.
The bladder is usually contractile, but because co-ordinated inhibition of the
distal sphincter mechanism does not occur (detrusor-sphincter dyssynergia), the
contractions are often high pressure and ineffective in producing complete
bladder emptying. The bladder neck is normally open in these patients. If left
untreated, the upper tracts suffer at the hands of the chronically full bladder
and raised intravesical pressure. Hydronephrosis and renal failure may result.
Capacity.
This is usually decreased after some years with the development of trabeculation
and a typical ‘fir-tree’ appearance of the bladder. The bladder pressure is
often increased and demonstrates marked phasic increases as the bladder tries to
contract and empty against the spastic sphincter mechanism.
Control.
The patients are incontinent during the high-pressure phasic contractions
because the sphincter resistance suddenly diminishes, allowing urinary leakage.
The
treatment of these patients depends on urodynamic assessment. Constant vigilance
is required, a watch being kept for hydronephrosis. This may be done by serial
intravenous urography (IVU) or ultrasound scanning. Regular follow-up urodynamic
investigations ate necessary. The patient with complete bladder emptying and
reasonable capacity with normal upper tracts may be managed by means of condom
drainage. The patient with incomplete bladder emptying and good capacity may be
managed by means of clean intermittent catheterisation (CISC). Patients with
poor emptying, low capacity and upper tract dilatation require additional
treatment. This may range from endoscopic sphincterotomy and condom drainage in
the male, which will allow complete bladder emptying at low ‘pressure, to
complete bladder reconstruction with bladder substitution using intestinal
segments and the fitment of artificial urinary sphincters, depending on the
mobility and motivation of the patient and available services.
Lesions involving the sympathetic outflow, T11 T12, L1, L2
These patients are usually similar to the
above group, but may have increased outflow resistance. alpha-Adrenergic blockers
may help.
Damage to the
sacral centre S2, 3, 4 and cauda equina lesions
This is essentially a lower motor neuron
bladder.
Emptying.
The detrusor is acontractile because there is injury to the parasympathetic
innervation. Abdominal straining and pressure on the bladder through the
abdominal wall can produce reasonable emptying in some patients. Nowadays, the
mainstay of management is the use of clean intermittent self-catheterisation
popularised by Lapides (CISC), which involves the patient passing themselves a
clean, but not sterile, catheter 2 or 3 hourly to ensure adequate bladder
emptying. Some patients may have a sensation of filling through the hypogastric
nerves if TI I and T12 are intact.
Capacity.
The bladder capacity may be good, but these patients may have high resting
bladder pressures and high tonic increases during bladder filling, which means
that if bladder emptying is incomplete there is a risk to the upper urinary
tract. The bladder neck is usually open and the distal sphincter mechanisms may
be paralysed, but the fixed urethral resistance prevents good bladder emptying
by means of straining. Vesicoureteric reflux is common and upper tract damage
is frequent in neglected cases.
Control.
Patients who can achieve satisfactory bladder emptying by means of CISC usually
have reasonable continence.
Persistent
retention of urine following excision of the rectum or radical hysterectomy
10 to 15 per cent of patients undergoing
radical rectal excision for cancer sustain damage to the inferior hypogastric
plexus leading to impotence in the male and neurogenic bladder dysfunction. This
type of bladder dysfunction is similar to the cauda equina lesion, but the
pressures during filling tend to be greater, leading to more incontinence and a
greater risk to the upper tracts. Postoperative retention in other patients is
simply caused by bladder outlet obstruction. The best plan is to catheterise the
patient with a 14 Fr silicone catheter, to allow a period for postoperative
recovery, and then carry out a urodynamic investigation which will distinguish
these two conditions. One requires treatment by means of prolonged CISC, while
the other will respond well to transurethral prostatectomy.