Postcaesarean Urinary Retention

Postcaesarean urinary retention is inability to empty the bladder after the catheter is removed, with a postvoid residual above 150 mL or a full painful bladder. It is caused by spinal or epidural anaesthesia, opioids, pain, bladder trauma and oedema, and haematoma in the pelvis or wound. It occurs in 1 to 5 percent of women and matters because overdistension damages the bladder muscle and causes infection.

• Risk factors: spinal opioids, long labour before surgery, perineal tear or haematoma, bladder injury, preeclampsia, diabetes, constipation.
• Most women recover bladder function within 24 to 48 hours of removing the catheter.
• Missed retention causes overflow incontinence.

Women have lower abdominal fullness and discomfort, urgency without passing urine, frequent small voids, or leakage. Examination shows a palpable bladder above the pubis, and the uterus may be displaced upward.

• Dull suprapubic mass that is tender.
• Small frequent voids with a sense of incomplete emptying.
• Differential diagnosis: oliguria from hypovolaemia, bladder or ureteric injury, urinary fistula, pelvic haematoma, urinary tract infection, neurological injury from anaesthesia, urethral obstruction.
• Complications: bladder overdistension, urinary infection, pyelonephritis, long term voiding dysfunction, bladder rupture, delayed mobilisation.

The approach is to measure bladder volume after a voiding attempt and to look for a cause.

• Postvoid residual by bladder ultrasound or in and out catheter after the woman has passed urine (above 150 mL confirms retention; above 500 mL is severe).
• Urinalysis and culture; creatinine; haemoglobin and examination for wound or pelvic haematoma.
• Neurological examination of legs, perineal sensation and anal tone if there is back pain or weakness.
• Ultrasound of the pelvis and kidneys when retention persists beyond 48 hours.

The principle is to drain the bladder promptly, then allow it to recover with a planned voiding check.

• Supportive: insert a Foley catheter 14 to 16 French and drain the bladder fully (drain slowly if above 1 litre); leave in for 24 to 48 hours; encourage mobilisation, privacy and warm water on the perineum; avoid constipation; repeat the voiding check after removal.
• Pharmacological: paracetamol 1 g oral 6-hourly (maximum 4 g in 24 hours) with diclofenac 50 mg oral 8-hourly for 3 days if no contraindication; lactulose 15 mL oral 12-hourly; cefalexin 500 mg oral 6-hourly for 5 days or nitrofurantoin 100 mg modified release oral 12-hourly for 5 days for urinary infection; naloxone 0.1 mg IV every 2 minutes up to 0.4 mg only when opioid sedation is present with a respiratory rate below 10 per minute.
• Procedures: clean intermittent self catheterisation every 4 to 6 hours for a postvoid residual above 150 mL after catheter removal; suprapubic catheter for failure of urethral catheterisation; drainage of a compressing haematoma.
• Special groups: back pain, leg weakness or saddle numbness after neuraxial anaesthesia needs urgent MRI for spinal haematoma or abscess and neurosurgical review.
• Red flags: no void 6 hours after catheter removal, bladder above 500 mL, fever above 38 degrees Celsius, loin pain, haematuria, saddle numbness or leg weakness.
• Follow-up: voiding and residual check before discharge; review at 1 week and 6 weeks; urodynamic assessment if symptoms persist beyond 6 weeks.