Surgery chapters
Acute and chronic urinary retention, urethral and suprapubic catheterisation
Causes, features and management of acute retention, chronic (high- and low-pressure) retention and overflow, post-obstructive diuresis, and the indications, technique and complications of urethral catheterisation, suprapubic catheterisation and clean intermittent self-catheterisation.
- Acute retention is painful inability to void with a tender palpable bladder, usually from BPH in men; relieve it with a urethral catheter (12–14F) and look for a precipitant (drugs, constipation, surgery).
- Chronic retention is painless, with a large residual; the high-pressure type causes bilateral hydronephrosis and renal failure, and draining it can cause post-obstructive diuresis.
- Use a suprapubic catheter when a urethral one fails or is unsafe (urethral injury, tight stricture), only into a palpable or ultrasound-confirmed bladder, after aspirating urine.
On this page
Overview
Retention of urine means the bladder cannot be emptied. It may be acute (sudden and painful) or chronic (slow and painless). Retention is one of the three commonest urological emergencies.
Catheterisation is a core house-officer skill. Exams test the causes of retention, how chronic retention damages the kidneys, how to pass a catheter safely, and when to choose the suprapubic route instead.
Acute urinary retention
Definition
A sudden, painful inability to pass urine, with a tender, distended, palpable bladder that is dull to percussion.
Causes
| Group | Causes |
|---|---|
| Men | Bladder outlet obstruction from BPH (commonest), urethral stricture, acute prostatitis or urethritis, prostate cancer, phimosis or meatal stenosis |
| Women | Retroverted gravid uterus, pelvic masses (fibroids, ovarian), bladder neck obstruction (rare), after childbirth or epidural, prolapse |
| Both sexes | Clot retention (haematuria), urethral stone, urethral rupture, faecal impaction, neurological (spinal cord injury or compression, cauda equina, multiple sclerosis, diabetes) |
| Postoperative | Pain (especially anal or perineal surgery, e.g. haemorrhoidectomy, hernia repair), spinal anaesthesia, opioids, immobility |
| Drugs | Anticholinergics, antihistamines (e.g. chlorphenamine), tricyclic antidepressants, α-agonist decongestants (e.g. pseudoephedrine), opioids, some antihypertensives |
Common precipitants in a man with an enlarged prostate: putting off voiding, a large alcohol (beer) load, constipation, an intercurrent illness, an operation, or a new drug.
Assessment
- History: previous LUTS, drugs, constipation, haematuria, back pain, neurological symptoms.
- Examination: palpable bladder; DRE (prostate size and consistency, anal tone, faecal loading); external genitalia (phimosis, meatal stenosis).
- Neurological check: lower-limb power and reflexes, perianal sensation and anal tone (to exclude cauda equina syndrome).
- U&E and creatinine; urine dipstick and culture after catheterisation.
Management
- Urethral catheter (12–14F Foley) under aseptic technique. A warm bath sometimes helps postoperative retention.
- Record the residual volume drained. A large residual suggests acute-on-chronic retention.
- Re-examine the abdomen after draining, to exclude other causes of pain (e.g. a leaking aortic aneurysm, ureteric colic, diverticulitis).
- Treat the precipitant (stop drugs, relieve constipation, treat infection).
- Start an α-blocker (e.g. tamsulosin) and try catheter removal after a few days. This works best with a short history and small residual.
- If voiding fails, or retention recurs in a fit man, offer TURP (or another prostatic operation). Unfit men can have a long-term catheter or a prostatic stent.
After catheterising a man in acute retention, always record the volume drained. A very large volume suggests a chronic element (acute-on-chronic retention), so renal function and urine output must be watched.
Chronic urinary retention
Definition
Painless, slowly developing incomplete emptying with a large residual volume (often taken as over about 250 mL). The bladder may be huge but the patient feels little.
Types
| Type | Features | Risk |
|---|---|---|
| Low-pressure chronic retention | Large, floppy, compliant bladder; low pressures | Kidneys usually safe |
| High-pressure chronic retention | High bladder pressure during filling and at rest | Bilateral hydronephrosis, renal impairment, hypertension |
Clinical features
- Painless, palpable bladder, often with loss of the suprapubic skin crease.
- Overflow incontinence: frequent small dribbles from a full bladder.
- Nocturnal enuresis (bedwetting) in an older man: a classic clue to high-pressure chronic retention.
- Uraemic symptoms, anaemia, dehydration.
- Acute-on-chronic retention: a man with chronic retention who suddenly cannot pass urine and has pain; the residual is very large.
Management
- Catheterise urgently if there is renal impairment or infection. If creatinine is normal and there is no infection, some men can go straight to prostatectomy without a catheter.
- Monitor for post-obstructive diuresis.
- Expect transient haematuria as the stretched bladder empties; it settles within a few days. Rapid decompression is acceptable; clamping is not needed.
- Once renal function is stable: TURP or other prostatic surgery; long-term catheter or clean intermittent self-catheterisation (CISC) if the detrusor is weak or the patient is unfit.
High-pressure chronic retention is the type that damages the kidneys (bilateral hydronephrosis, raised creatinine); low-pressure chronic retention usually spares them.
Post-obstructive diuresis
After relief of high-pressure chronic retention the damaged tubules cannot concentrate urine or reabsorb salt. Retained urea also acts as an osmotic diuretic. The patient may pass very large volumes of dilute urine for several days.
- Keep a strict fluid balance chart, daily weight and serial U&E.
- Allow the patient to drink; give IV saline if he cannot keep up with the losses.
- Danger: dehydration, hypotension, hyponatraemia or hypokalaemia.
Acute retention hurts; chronic retention does not. A painless distended bladder with renal failure and bedwetting is high-pressure chronic retention, and the urgent concern is the kidneys, not the pain.
Urethral catheterisation
Indications
- Relief of retention (acute or chronic).
- Accurate urine output monitoring (sepsis, shock, major surgery, burns).
- Before and during some operations (pelvic, long procedures, epidural).
- Clot retention and bladder irrigation (three-way catheter) after TURP or with haematuria.
- Investigations (urodynamics, cystography), bladder drug instillation (mitomycin C, BCG), and intractable incontinence.
Contraindications
- Suspected urethral injury: blood at the meatus, perineal or scrotal bruising, a high-riding prostate, a pelvic fracture. A retrograde urethrogram comes first; drainage is by suprapubic catheter.
- Known tight stricture or false passage (relative).
- Acute prostatitis (relative; suprapubic route preferred).
Catheter types and sizes
- Size is in French (Charrière) gauge: the external circumference in millimetres. Diameter in mm is about F ÷ 3.
- 12–14F for routine adult drainage; larger three-way catheters for clots and irrigation.
- Foley catheter: self-retaining balloon. Two-way (drain + balloon) or three-way (drain + balloon + irrigation).
- Coudé (curved) tip: helps pass an elevated bladder neck or prostatic median lobe.
- Materials: latex for short-term use; silicone for long-term use and latex allergy.
A 14F catheter has a circumference of 14 mm.
Diameter = 14 ÷ π = about 4.5 mm (roughly 14 ÷ 3)
So a 12F catheter is about 4 mm across.
Technique (male)
- Consent; check for latex allergy; hand wash, sterile gloves and drapes.
- Retract the foreskin and clean the glans and meatus.
- Instil lidocaine gel into the urethra; massage it back towards the sphincter and wait a few minutes (a penile clamp helps).
- Hold the penis taut and upward (to straighten the urethra) and advance the catheter gently.
- Advance until urine flows, then pass it a few more centimetres (ideally to the hilt) before inflating the balloon, so the balloon is not blown up in the prostatic urethra.
- Inflate the balloon with the volume printed on the catheter (sterile water); withdraw gently until it rests at the bladder neck.
- Connect to a closed sterile drainage bag kept below bladder level.
- Replace the foreskin to prevent paraphimosis.
- Record the residual volume and document size, type and balloon volume.
Female: part the labia with the non-dominant hand, which should then stay in place; clean, insert gel, pass the catheter into the meatus above the vaginal opening.
Never force a catheter.
If the catheter will not pass
- Common reasons: poor technique, too little anaesthetic gel or time, a stricture, a large median lobe, or an earlier false passage.
- Options: try a coudé catheter; call a urologist; dilatation or urethrotomy in a known stricture; otherwise suprapubic catheterisation.
Complications of urethral catheters
| Early | Late (long-term catheters) |
|---|---|
| False passage, urethral trauma and bleeding | Catheter-associated bacteriuria (almost universal) and UTI |
| Balloon inflated in the prostatic urethra | Encrustation and blockage |
| Paraphimosis (foreskin not replaced) | Bladder stones |
| Bacteraemia | Urethral stricture (meatus, bulbar), urethral erosion |
| Haematuria after decompression | Bladder spasm and bypassing |
| Squamous metaplasia; rare squamous cell carcinoma after many years |
Retained catheter (balloon will not deflate)
The inflation channel is usually blocked near the balloon. Options: cut the side arm; pass a fine wire up the channel; over-inflate the balloon to burst it; or puncture the balloon with a needle under ultrasound guidance. Afterwards, cystoscopy removes balloon fragments, which would otherwise seed a bladder stone.
Suprapubic catheterisation
Indications
- Failed urethral catheterisation in retention.
- Urethral injury (pelvic fracture with blood at the meatus; straddle injury).
- Urethral stricture in retention (the lumen may be too narrow even for a fine catheter).
- Long-term catheter users (more comfortable, less urethral damage, sexual activity possible, easier to change); neurogenic bladder.
- Acute prostatitis; after some pelvic or urethral surgery.
Contraindications and cautions
- Bladder not palpable and not seen on ultrasound (risk of bowel injury).
- Previous lower abdominal or pelvic surgery (adherent bowel): use ultrasound guidance or an open approach.
- Known or suspected bladder cancer (tumour seeding along the track).
- Uncorrected bleeding disorder or anticoagulation.
- Abdominal wall sepsis.
Technique (percutaneous)
- Confirm a full bladder by palpation, percussion or ultrasound.
- Choose a point in the midline just above the pubic symphysis.
- Local anaesthetic to skin, fascia and the retropubic space.
- Aspirate urine with the needle to confirm the bladder is reached. If no urine is aspirated, do not pass the trocar.
- Insert the catheter: a fine catheter through a large-bore needle (e.g. Cystofix), a trocar-and-cannula system with a peel-away strip through which a 12F Foley is passed (e.g. Add-a-Cath), or a Seldinger technique with dilators.
- Inflate the balloon, secure it and attach a drainage bag.
- If no kit is available, place the catheter under direct vision through a small incision (open suprapubic cystostomy).
Complications
- Bowel perforation (most serious; peritonitis).
- Bleeding and haematuria.
- Infection, cellulitis at the site, leakage, blockage, displacement.
- Bladder spasm; later stones and encrustation.
"No urine, no trocar." Always aspirate urine through the needle first.
In a man with a pelvic fracture and blood at the meatus, do not pass a urethral catheter. Perform a retrograde urethrogram and drain the bladder suprapubically.
Clean intermittent self-catheterisation (CISC)
A clean (not sterile) catheter is passed several times a day and removed after each void. Popularised by Lapides.
- Uses: neurogenic bladder (spina bifida, spinal injury, multiple sclerosis, diabetic neuropathy), weak detrusor with chronic retention, after detrusor botulinum toxin injection, some strictures (self-dilatation).
- Advantages: lower infection rate than an indwelling catheter, protects the upper tracts, better continence and body image.
Retention in neurological disease
| Lesion | Bladder type | Management |
|---|---|---|
| Spinal shock (just after cord injury) | Acontractile, retention and overflow | Catheter; then intermittent catheterisation once stable; high fluid intake |
| Above T10 (upper motor neuron) | Reflex, overactive, detrusor–sphincter dyssynergia, high pressure; risk of autonomic dysreflexia | CISC ± anticholinergics; protect kidneys |
| Sacral cord S2–S4 or cauda equina (lower motor neuron) | Acontractile, large capacity | CISC |
| Pelvic surgery (abdominoperineal excision, radical hysterectomy) | Pelvic plexus injury → poor emptying | Catheter, then urodynamics |
A man with a spinal injury, sudden pounding headache, very high blood pressure and a slow pulse has autonomic dysreflexia, often from a blocked catheter. Sit him up and relieve the bladder first.
Expect: causes of acute retention (BPH, drugs such as anticholinergics and antihistamines, postoperative, retroverted gravid uterus), acute versus chronic retention, high-pressure chronic retention with hydronephrosis and enuresis, post-obstructive diuresis, catheter technique (inflate after urine flows, replace foreskin), the French gauge, coudé catheters, contraindications to urethral catheterisation in pelvic fracture, suprapubic catheter indications and the rule to aspirate urine first, retained balloons, and CISC in neurogenic bladder.
Quick revision
- Acute retention: painful; BPH commonest; look for drugs, constipation, surgery, alcohol.
- Women: retroverted gravid uterus, pelvic masses, postpartum.
- Catheter 12–14F; French = circumference in mm.
- Inflate balloon only after urine flows; replace the foreskin.
- Blood at meatus/pelvic fracture → urethrogram, suprapubic drainage.
- Chronic retention: painless; high-pressure type → hydronephrosis, renal failure, bedwetting.
- Post-obstructive diuresis: fluid chart, weights, U&E, IV saline if needed.
- Suprapubic: palpable bladder, aspirate urine first; avoid in suspected bladder cancer.
- Neurogenic bladder → CISC.
Written by The House Job from standard references (Bailey & Love; Kumar and Clark's Clinical Medicine).
FAQ
What is the most common cause of acute urinary retention?
In men it is bladder outlet obstruction from benign prostatic enlargement, often set off by delayed voiding, alcohol, constipation, surgery or an anticholinergic drug.
How is chronic retention different from acute retention?
Chronic retention develops slowly and is painless, with a large residual volume; the high-pressure form damages the kidneys. Acute retention is sudden and painful.
Why must the catheter balloon not be inflated until urine flows?
Urine flow shows the tip is in the bladder. Inflating it in the prostatic urethra causes pain, bleeding and urethral damage.
When should a suprapubic catheter be used instead of a urethral one?
When a urethral catheter fails or is unsafe, as in urethral injury or a tight stricture, and for many long-term catheter users, provided the bladder is clearly palpable or seen on ultrasound.