Acute urinary retention

Question 1

Acute urinary retention

Answer 1

New onset inability to pass urine

Question 2

Acute-On-Chronic Retention

Answer 2

Acute retention on a background of chronic retention

Minimal discomfort despite large residual volumes

Question 3

Causes

Answer 3

Most common: BPH

Urethral strictures - due to UTI

Prostate cancer

Constipation - compression of urethra

Severe pain

Medication

Neurological:

• peripheral neuropathy
• iatrogenic nerve damage during pelvic surgery
• upper motor neurone disease
• Bladder Sphincter Dysinergy

Question 4

Which medication can cause acute urinary retention

Answer 4

Anti-muscarinic

Spinal or epidural anaesthesia

Question 5

Clinical features

Answer 5

Acute suprapubic pain
Palpable distended bladder

Symptoms of UTI
Change in medication

Question 6

Investigations

Answer 6

DRE 
Post void bladder scan 
Routine bloods 
Catheterised Specimen of Urine
High pressure retention - USS

Question 7

High pressure retention

Answer 7

Caused by high intra-vesicular pressures that overcome urethral valves

Can cause hydronephrosis

Repeat high pressure retention can causes CKD

Question 8

Low pressure retention

Answer 8

Retention with the upper renal tract unaffected due competent urethral valves or reduced detrusor muscle contractility / complete detrusor failure

Question 9

Management

Answer 9

Immediate urethral catheterisation
- measure the volume drained post-catheterisation + residual volume

Treat underlying cause

TWOC (Trial with out Catheter)

Question 10

Tx for BPH

Answer 10

Tamsulosin - alpha blocker

+/- Finasteride - 5 alpha reductase inhibitor

TURP

Question 11

Large retention volume

Answer 11

> 1000ml

Monitor urine output for 24hrs post-catheterisation for post-obstructive diuresis

Question 12

Post-Obstructive Diuresis consequences

Answer 12

Can worsen AKI

Patients producing >200ml/hr urine output should have 50% of their urine output replaced with intravenous fluids

Question 13

Mx of high-pressure urinary retention

Answer 13

Keep catheter in-situ until definitive management can be arranged (e.g. TURP)

Question 14

TWOC

Answer 14

Catheter removed 24-48hrs after insertion.

If the patient voids successfully, with a minimal residual volume - successful

Re-enters retention, the patient will - require re-catheterisation

Question 15

What receptors provide the main parasympathetic supply to the bladder

Answer 15

M3