Prostatic acute urinary obstruction

Question 1

What is prostatic acute urinary obstruction?

Answer 1

• Urinary retention of sudden onset leading to pain and discomfort and significant residual volumes
• Due to an enlarged prostate (typical in older males)

Question 2

What is the presentation of prostatic acute urinary obstruction?

Answer 2

• Acute suprapubic pain
• inability to pass urine
• urinary symptoms possible
• palpable distended bladder

Question 3

What investigations are required?

Answer 3

• post-void bedside bladder scan -showing volume of retained urine
• routine bloods
• post catheterisation a catheterised specimen of urine
• patients with features of high-pressure urinary retention will require ultrasound scan of urinary tract to assess presence of associated hydronephrosis

Question 4

What is high-pressure urinary retention?

Answer 4

*Urinary retention causing such high intra-vesicular pressures that the anti-reflux mechanism of bladder and ureters is overcome an dback us leading to hydroureter and hydronephrosis

Question 5

What is the management of prostatic acute urinary retention?

Answer 5

1. Immediate catheterisation to resolve retention
   >measure volume drained post-catheter
2. Enlarge prostate treated with alpha receptor antagonist i.e. Tamsulosin
3. Check catheter urine sample for evidence of infection and treat with antibiotics if needed
4. Urine output monitored for 24hrs to check for post-obstructive diuresis

Question 6

What is post-obstructive diuresis?

Answer 6

• Following resolution of the retention through catheterisation, the kidneys can often over-diurese due to the loss of their medullary concentration gradient,
• over-diuresis can lead to a worsening AKI