Makindo Medical Notes

Related Subjects: |Acute Urinary Retention |Chronic Urinary Retention |Urinary Catheterisation

ℹ️ Definition

• Chronic urinary retention = painless bladder distension with residual volume >300 ml after voiding, developing gradually over weeks to months.
• 👴 Common in older men, usually from lower urinary tract obstruction (especially BPH).
• High intravesical pressure can → bilateral hydronephrosis → chronic kidney disease.

📊 Classification

• High-pressure chronic retention (HPCR): Detrusor pressures >30 cmH₂O, bilateral hydronephrosis, risk of renal impairment. Requires urgent decompression.
• Low-pressure chronic retention (LPCR): Detrusor pressures <30 cmH₂O, no hydronephrosis, minimal renal risk. Can be managed conservatively.

🔍 Acute vs Chronic Urinary Retention

🚨 Acute Retention

• Onset: Sudden, develops within hours.
• Symptoms: Painful, severe suprapubic discomfort, complete inability to void, extreme urgency.
• Bladder: Palpable, tense, tender, distended (typically >500 ml).
• Renal Risk: Acute Kidney Injury (AKI) if untreated due to back-pressure on kidneys.
• Common Causes: BPH exacerbation, urethral obstruction (stone, stricture), drugs (anticholinergics, opioids, sympathomimetics), post-operative retention, constipation, infection.
• Urgency: ⚠️ Immediate catheterisation required to relieve obstruction and pain.
• Investigations: Bladder scan (>500 ml), post-catheter residual volume, FBC, U&E (check for AKI), PSA (after 48 hours, not acutely).
• Management: Immediate urethral catheterisation (14–16 Fr), start α-blocker (e.g., tamsulosin 400 mcg OD), address precipitants, plan Trial Without Catheter (TWOC) after 1–3 days.
• Complications: Severe pain, bladder rupture (rare), post-obstructive diuresis, AKI.

🕐 Chronic Retention

• Onset: Gradual, develops over weeks to months or years.
• Symptoms: Usually painless, overflow incontinence, nocturia, LUTS (hesitancy, poor stream, incomplete emptying), recurrent UTIs.
• Bladder: Palpable (may reach umbilicus), very large (>800 ml common), typically non-tender.
• Renal Risk: Bilateral hydronephrosis → chronic kidney disease if high-pressure retention.
• Common Causes: Long-standing BPH, neurogenic bladder (diabetes, MS, spinal cord lesions), urethral stricture, detrusor underactivity.
• Urgency: Less urgent — but assess for high-pressure retention (hydronephrosis/AKI) requiring urgent decompression.
• Investigations: USS bladder (residual >300 ml diagnostic), renal USS (assess for hydronephrosis), U&E (renal function), PSA, urodynamics if diagnosis unclear, cystoscopy to assess bladder/prostate.
• Management: Medical therapy (α-blocker ± 5-α reductase inhibitor if large prostate), intermittent self-catheterisation (ISC) preferred over indwelling catheter, suprapubic catheter (SPC) if long-term catheterisation needed, surgery if medical therapy fails or complications arise.
• Complications: Recurrent UTIs, bladder stones, bladder diverticula, chronic renal impairment, overflow incontinence, post-obstructive diuresis after decompression.

⚠️ Causes

• Obstructive (most common):
  • 👴 Benign prostatic hyperplasia (BPH) – commonest in men.
  • Prostate cancer.
  • Urethral stricture (trauma, instrumentation, infection).
  • ♀️ Pelvic organ prolapse (cystocele, rectocele) – women.
  • Bladder neck obstruction.
  • Urethral/bladder tumour.
  • Faecal impaction.
• Neurogenic:
  • Diabetes mellitus (autonomic neuropathy).
  • Multiple sclerosis, Parkinson's disease.
  • Spinal cord injury/compression (cauda equina syndrome).
  • Stroke, cerebrovascular disease.
  • Guillain-Barré syndrome.
  • Peripheral neuropathy.
• Infective: Herpes simplex virus (HSV), severe UTI.
• Pharmacological: Anticholinergics, opioids, tricyclic antidepressants, sympathomimetics, calcium channel blockers.
• Other: Detrusor underactivity (idiopathic), post-surgical (pelvic surgery).

🧑‍⚕️ Clinical Features

• Typically painless retention with high residual urine volume (>300 ml, often >800 ml).
• Lower urinary tract symptoms (LUTS): Hesitancy, weak stream, straining, incomplete emptying, terminal dribbling.
• Storage symptoms: Frequency, nocturia, urgency.
• Overflow incontinence: Continuous dribbling of urine, worse on standing/straining.
• Large palpable bladder 🫙 (dull to percussion, may extend to umbilicus or beyond).
• Signs of renal impairment: Oedema, hypertension, uraemic symptoms if advanced.
• ⚠️ Always exclude neurological disease: Saddle anaesthesia, lower limb weakness, altered perineal sensation, reduced anal tone (cauda equina syndrome).
• Digital rectal examination (DRE): Assess prostate size, consistency, symmetry.

🔍 Investigations

• Bladder USS/scan: Large atonic bladder, high post-void residual volume (>300 ml diagnostic, often >800 ml).
• Renal USS: Assess for hydronephrosis (indicates high-pressure retention), assess renal size/cortical thickness.
• Blood tests:
  • U&E: Assess renal function (raised creatinine/urea if obstructive uropathy).
  • FBC: Rule out anaemia of CKD or infection.
  • CRP: If infection suspected.
  • PSA: Measure after catheterisation or after retention resolved (elevated in BPH, infection, and malignancy).
• Urine: Dipstick (check for leucocytes, nitrites, blood), MC&S if UTI suspected.
• Urodynamics: Consider if diagnosis unclear or planning surgery (assesses detrusor function, capacity, compliance).
• Cystoscopy: If suspicion of bladder pathology, obstruction, or structural abnormality.
• MRI spine: If neurological signs present to exclude cord compression.

⚕️ Management

🚨 Immediate Management (High-Pressure Retention)

• Urgent catheterisation if hydronephrosis/renal impairment present.
• Monitor for post-obstructive diuresis: Can lose >200 ml/hour urine. Monitor fluid balance, U&E. Replace losses if excessive (IV fluids).
• Serial U&E to monitor renal recovery.

💊 Medical Management

• Alpha-blockers (α-blockers): Tamsulosin 400 mcg OD, Alfuzosin 10 mg OD, Doxazosin 1–8 mg OD.
  • Relax smooth muscle in prostate/bladder neck.
  • Rapid onset (days to weeks).
  • Side effects: Postural hypotension, dizziness, retrograde ejaculation.
• 5-alpha reductase inhibitors (5-ARIs): Finasteride 5 mg OD, Dutasteride 500 mcg OD.
  • Reduce prostate size (only if prostate >30 g or PSA >1.4 ng/ml).
  • Slow onset (3–6 months for full effect).
  • Side effects: Reduced libido, erectile dysfunction, gynaecomastia.
  • Reduces PSA by ~50% (consider when interpreting PSA).
• Combination therapy: α-blocker + 5-ARI for large prostates with bothersome LUTS. More effective than monotherapy.
• Antimuscarinic/β3-agonist: Consider if predominant storage symptoms (after excluding retention risk).

🩺 Catheterisation Strategy

• 📌 Intermittent self-catheterisation (ISC): Preferred long-term option. Maintains bladder function, lower infection risk, preserves quality of life. Teach clean technique (4–6 times daily).
• Indwelling urethral catheter: If ISC not feasible (manual dexterity issues, cognitive impairment, patient preference). Use smallest size (12–14 Fr). Change every 12 weeks.
• Suprapubic catheter (SPC): If long-term catheterisation needed and urethral catheter problematic (urethral trauma, strictures, patient preference). Reduces urethral complications, easier to change.
• Risks of long-term catheter: Recurrent UTIs, encrustation/blockage, urethral trauma/stricture, bladder stones, discomfort, reduced quality of life.

🔪 Surgical Management

• Indications for surgery:
  • Failure of medical therapy (persistent bothersome LUTS).
  • Acute urinary retention (AUR) unresponsive to TWOC.
  • Recurrent acute retention.
  • Recurrent or persistent UTIs despite treatment.
  • Recurrent frank haematuria due to BPH.
  • Bladder stones.
  • Acute or chronic renal failure due to obstruction.
  • Large bladder diverticula.
• Surgical options:
  • TURP (transurethral resection of prostate) – gold standard for prostates <80 g.
  • Laser prostatectomy (HoLEP, GreenLight) – lower bleeding risk, suitable for anticoagulation.
  • Open prostatectomy – for very large prostates (>80–100 g).
  • Urethral dilation/optical urethrotomy – for strictures.
  • Bladder neck incision – for bladder neck obstruction.
• 🚑 Urology referral if severe symptoms, complications, or surgical intervention required.
• ♀️ Gynaecology referral for women with prolapse-related retention (consider pessary or surgical repair).

🏥 Supportive Management

• Treat contributory factors: UTI (antibiotics), constipation (laxatives), medications (stop/reduce anticholinergics, opioids), mobility issues (physiotherapy).
• Manage CKD: If renal impairment develops, involve nephrology. Monitor U&E, manage hypertension, anaemia, bone health.
• Lifestyle advice: Avoid excessive fluid intake before bed, reduce caffeine/alcohol, regular voiding, pelvic floor exercises.
• Follow-up: Review response to medical therapy at 4–6 weeks, then 3–6 months. Monitor PSA, renal function, residual volumes.

⚠️ Post-Catheterisation Complications

• Post-obstructive diuresis: Massive diuresis (>200 ml/hour) after relieving chronic obstruction. Risk of dehydration, electrolyte imbalance. Monitor fluid balance, replace losses cautiously (0.45% saline or oral fluids). Usually self-limiting within 24–72 hours.
• Haematuria: Common after catheterisation in chronic retention (bladder mucosa trauma). Usually settles with catheter drainage ± bladder irrigation.
• Hypotension: Rare, may occur with rapid bladder decompression. Slow drainage if very large volume (clamp intermittently if needed).

⚠️ Cautions for Catheterisation

• Recent urethral/prostate surgery (risk of disrupting anastomosis).
• Unexplained urethral bleeding/haematuria (investigate cause first).
• History of false passage, urethral strictures (consider suprapubic catheter or senior/urology input).
• Pelvic/perineal trauma, fractured pelvis (risk of urethral injury – do not attempt urethral catheter if blood at meatus).
• Acute prostatitis (painful, but may need catheterisation – consider suprapubic route).

🎯 Trial Without Catheter (TWOC)

• Performed after acute retention once precipitants addressed (typically after 1–3 days).
• Start α-blocker before TWOC (improves success rate to ~60%).
• Remove catheter early morning, monitor voiding, measure residual volume.
• Success = voiding >150–200 ml with residual <200 ml.
• If failed TWOC: Consider longer catheterisation (1–4 weeks) + 5-ARI if large prostate, or urology referral for surgery.

📚 References

• NICE CG97: Lower Urinary Tract Symptoms in Men
• BAUS Guidelines: Management of Lower Urinary Tract Symptoms