Urinary retention

Question 1

Define

Answer 1

inability to pass urine

Question 2

Acute urinary retention

Answer 2

new onset inability to pass urine, leading to pain and discomfort with significant residual volumes

Question 3

Risk Factors

Answer 3

Older male
BPH
UTI
Constipation
Severe pain
Medications
-antimuscarinics or spinal or epidural anaesthesia
Neurological causes
-peripheral neuropathy
-iatrogenic nerve damage dt surgery
-upper motor neurone disease (multiple sclerosis, parkinson's ds)

Question 4

Clinical features

Answer 4

Acute suprapubic pain
inability to micturate
worsening voiding LUTS

Question 5

Investigations

Answer 5

post-void bedside bladder scan
-show the vol of retained urine to confirm the diagnosis
Routine bloods
CSU (catheterised specimen of urine)
USS of UT to assess the presence of ass hydronephrosis

Question 6

High Pressure urinary retention

Answer 6

High Pressure Urinary Retention refers to the urinary retention causing such high intra-vesicular pressures that the anti-reflux mechanism of the bladder and ureters is overcome and ‘backs up’ into the upper renal tract leading to hydroureter and hydronephrosis, impairing the kidneys’ clearance levels.

Such patients present in retention with associated deranged renal function, and hydronephrosis will be subsequently confirmed on imaging (typically ultrasound as first line). Repeat episodes of high-pressure chronic retention can cause permanent renal scarring and chronic kidney disease (CKD).

By contrast, low pressure retention occurs in patients with retention with the upper renal tract unaffected due competent urethral valves or reduced detrusor muscle contractility / complete detrusor failure.