Acute urinary retention

Question 1

What is AUR?

Answer 1

• New onset
• Inability to pass urine (or passing very small quantities)
• Which subsequently leads to pain and discomfort
• With significant residual volumes

Question 2

What is acute-on-chronic retention?

Answer 2

• Chronic retention can enter acute retention
• Can be due to acute deterioration of underlying pathology that caused chronic retention or a new cause - superimposed onto background of previous cause
• Minimal discomfort despite LARGE residual volumes
• More at risk of post-obstructive diuresis due to higher residual volumes

Question 3

Most common causes of AUR

Answer 3

• BPH
• Urethral strictures
• Prostate cancer
• Others - constipation, severe pain, antimuscarinics, anaesthesia (spinal/epidural), neurological disease (eg MS, parkinsons)

Question 4

What is detrusor sphincter dyssynergia?

Answer 4

• Lack of co-ordination of detrusor muscle contraction with urethral sphincter relaxation
• = contraction against closed sphincter
• Often seen in spinal cord pathology/trauma

Question 5

Symptoms of acute urinary retention

Answer 5

• Acute suprapubic pain
• Inability to micturate
• Associated symptoms of underying cause eg UTI, worsening voiding LUTs, recent change meds

Question 6

Examination of AUR

Answer 6

• Palpable distended bladder
• Suprapubic tenderness
• Fevers, rigors, lethargy may suggest infective cause
• DRE needed - assess prostate and constipation

Question 7

Bedside and bloods for AUR

Answer 7

• Post void bladder scan
• Bloods - FBC, CRP, U&E
• Post catheterisation - catheterised specimen of urine (CSU) send for MC&S

Question 8

If patient drains >1000ml on catheterisation, what needs to be ruled out?

Answer 8

• High pressure chronic retention
• This can have caused bilateral hydronephrosis or AKI

Question 9

Imaging for AUR if suspect high pressure retention

Answer 9

USS of KUB to assess for presence of hydronephrosis

Question 10

Management of AUR

Answer 10

• Immediate urethral catheterisation
• Measure volume drained post cathterisation
• Treat underlying cause eg if BPH Tamsulosin
• Check CSU for any infection
• Review meds for potential causes

Question 11

When is catheter removed in AUR?

Answer 11

• If patients have no evidence of renal impairement do TWOC
• If history of chronic LUTS or palpable large prostate start on alpha 1 adrenoreceptor blocker (eg Tamsulosin) and have TWOC 72hrs or more after commencing

Question 12

When is TWOC successful?

Answer 12

• If voids with minimal residual volume (less 50-100ml usually)
• = successful
• If not, further TWOCs can be trialled in specialist TWOC clinic but multiple failed attempts may require long term catheter until definitive management can be arranged

Question 13

Complications of AUR

Answer 13

• If acute on chronic - AKI –> CKD
• Increase risk UTI and renal stones (due to urine stasis)

Question 14

What is post obstructive diuresis?

Answer 14

• Urine production exceeding 200 mL per hour for 2 consecutive hours OR
• Producing greater than 3 L of urine in 24 hours is diagnostic of POD
• = excessive loss of electrolytes and water