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

  The most frequent causes of 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, septicaemia and abscess formation elsewhere. In such patients, the change of catheter should be covered by appropriate prophylactic antibiotics.

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.

  1. The bladder must be kept empty either by intermittent catheterisation with an aseptic technique performed two or three times daily, or by the use of an indwelling urethral catheter on continuous drainage and making sure that the patient has a high urinary output (3 litres/day) to combat infection. Currently, the use of intermittent catheterisation is preferred as soon as the patient can be moved when the spinal injury is stable.

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.

  The results of these studies should enable decisions to be made as to the further management of the bladder, the prime aim being to prevent upper tract damage by promoting good bladder emptying and to avoid infection. The following situations represent only the typical pattern of bladder function.

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.