Follow up

AUR secondary to constipation, UTI with no previous urinary tract symptoms and postoperative pain does not need follow up. Trial without catheter (TWOC) may be attempted.

Although the role of early TWOC is debated, in these conditions it may be feasible with a residual volume of less than one litre⁶. Referral to a urology clinic with a catheter in situ is advised for most patients.

BPH features may be an indication to prescribe alpha blockers¹⁰although this is often determined by local protocols.

Types of Catheter

A Cochrane review¹⁴ has found that patients requiring catheterisation for fourteen days had less bacteruria, discomfort and decreased need for recatheterisation when supapubic catheters (SPCs) were used. Another Cochrane review found in patients requiring catheterisation for 14 days or less that silver alloy impregnated catheters have been associated with decreased rates of UTI¹⁷. In both cases, practical considerations have made their usage infrequent (Level 1A).

When to Remove Catheter

Another Cochrane review found there is suggestive, but inconclusive, evidence of a benefit from midnight removal of the in-dwelling urethral catheter. The evidence also suggests shorter hospital stay after early rather than delayed catheter removal, but the effects on other outcomes are unclear. There is little evidence on which to judge other aspects of management such as catheter clamping (Level 2A).

Finasteride

In another Systematic review, it was found that finasteride significantly reduced the risk of acute urinary retention and prostatectomy compared with placebo (urinary retention: 6.6% with placebo v.2.8% with finasteride; NNT 26, 95% CI 22 to 38; prostatectomy: 8.3% with placebo v.4.2% with finasteride; NNT 24, 95% CI 19 to 37)¹⁰. It also found that finasteride significantly reduced the risks of acute urinary retention and the need for invasive therapy compared with placebo (risk reduction for acute urinary retention: 68%; P = 0.009; risk reduction for invasive therapy: 64%; P<0.001).

Learning Bite:

Urology referral is appropriate in the majority of cases of acute urinary retention, as this group of patients are likely to need surgical intervention in the future.

Learning Bite:

SPCs offer easier TWOC, lower rates of UTIs⁷ and fewer urethral strictures¹¹ in comparison to urethral catheters, but practical considerations have made their usage infrequent.

Suprapubic Catherterisation

The Bonanno technique uses a small calibre catheter with a needle for puncture within the lumen.

The other technique of suprapubic catheterisation utilises the ‘Bard’ trocar model.

Essentially the techniques are similar. Ensure there is adequate filling of the bladder, confirm by ultrasound, and utilise direct puncture behind the pubic bone angled downwards with the Bonanno or utilise a skin nick with blade contained in the kit and the trocar. Local anaesthesia is essential in both cases.

Bonanno technique

‘Bard’ Trocar model

Removal of a Non Deflating Catheter

Encountering difficulty when removing a catheter is a common problem. Several solutions have been described to deflate the balloon. Cutting the catheter itself only works when the valve flap that retains fluid is in the external segment. Overinflation may require up to 200 mls of fluid and always leaves retained balloon pieces that unless removed endoscopically, will act as a nidus for infection or stone formation⁸.

Retention of catheter fragments is also common when corrosive substances such as ether and acetone are used. As these substances can cause a chemical cystitis they should not be used.

Ultrasound guidance may be used to rupture the balloon transabdominally. Sliding a central line guidewire down the balloon channel to release the retaining valve can also be effective. Again, in all cases, the balloon must be inspected to determine whether cystoscopy is necessary to remove fragments.

Prostate Examination

Remember the prostate is a heart shaped organ with the apex located distally. There is debate regarding prostate examination raising prostate specific antigen (PSA) and contaminating mid stream urine (MSU) collection.

Try and distinguish tenderness of the gland from the expected discomfort of a normal examination. A normal prostate can be said to feel like the end of a nose in consistency whereas cancerous nodules are said to feel more like the bony area of the chin.

Most cancer arises in the lateral areas of the gland. The severity of prostatic hypertrophy is more accurately determined by the severity of symptoms and size of residual volume than the actual size on rectal examination.

Pitfalls

Common Problems with Catheters

• If there is phimosis and the opening is adequate, try to pass the catheter blind. If the opening is too narrow, try a smaller catheter. If in doubt, seek more expert help
• If the catheter will not pass the prostate, try a catheter with a larger diameter. The urethra at the site of the prostate is not narrow, but it is pushed flat by the surrounding prostate. A larger catheter pushes the prostate lobes back to the side to allow passage. Another option is to try a silicone catheter, as it is more rigid than a silicon latex catheter
• If the catheter does not pass the bladder neck, try a smaller size

Learning Bite:

significant renal impairment +/- complications, significant post obstruction diuresis, sepsis, dehydration, and inability to manage at home e.g. dementia⁴.

Female AUR

Female acute urinary retention (AUR) is relatively uncommon and often poorly managed. There are several common precipitants.

The underlying abnormality is often detrusor failure, not outlet obstruction. Investigations should focus on identifying serious or reversible causes and should include a detailed history and physical examination, urine dipstick, culture and pelvic ultrasound.

Pelvic examination, neurological assessment, urine culture and pelvic ultrasound should be performed on all females with AUR. Patients should be catheterised and reversible causes should be treated. Patients with apparently idiopathic retention should be referred to a urologist with an interest in bladder dysfunction for consideration of urodynamics.