urology

1. Adhil hasbulla
119i4a
Urology

2.  Urinary retention is as an inability to pass urine. It can be
divided into either acute or chronic urinary retention.
 Acute urinary retention is defined as a new onset inability to
pass urine, which subsequently leads to pain and discomfort,
with significant residual volumes.
 The condition is most prevalent in older male patients,
typically due to an enlarged prostate leading to bladder
outflow obstruction, however there are a wide array of
potential causes.

3.  The most common cause in men is BPH. Other common
obstructive causes include urethral strictures or prostate cancer.
 UTI can cause the urethral sphincter to close. Constipation can
also cause acute retention, through compression on the urethra.
 Neurological causes can include peripheral neuropathy, iatrogenic
nerve damage during pelvic surgery, upper motor neurone disease
(such as Multiple Sclerosis, Parkinson’s disease), or Bladder
Sphincter Dyssinergia.
 Severe pain can often cause patients to enter acute retention.
Medications, such as anti-muscarinics or spinal or epidural
anaesthesia, can affect innervation to the bladder, resulting in
acute retention.

4. Bladder Sphincter Dysinergy is the lack of co-ordination
of detrusor muscle contraction with urethral sphincter
relaxation, leading to contraction against a closed
sphincter, often seen with spinal cord pathology or
traumatic injury.

5.  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.
 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 or
complete detrusor failure.

6.  Acute suprapubic pain and an inability to micturate.
This may be associated with symptoms suggestive of the
predisposing cause, such as a urinary tract infection, change to
medication, or worsening voiding LUTS.
 Any associated fevers/rigors or lethargy may suggest an infective
cause. Ensure to perform a PR examination, especially in elderly
patients, to assess for any prostate enlargement or constipation.

7. On examination, the patient will have
a palpable distended bladder, with
suprapubic tenderness

8.  All patients require routine bloods, especially a FBC, CRP, and
U&Es . Post-catheterisation, a CSU (Catheterised Specimen of
Urine) should also be sent to assess for the presence of infection.
 Patients with features of high-pressure retention will require an
ultrasound scan of their urinary tract to assess for the presence of
associated hydronephrosis. If this is confirmed, follow-up repeat
imaging will be required.
A post-void bedside bladder scan
will show the volume of retained urine
helping to confirm the diagnosis.

9. A bladder in retention
Post Void USG

10.  Patients will warrant immediate urethral catheterisation to resolve
the retention. Ensure to measure the volume drained post-
catheterisation.
 The underlying causes should then be treated accordingly.
 Ensure to check for any evidence of infection and treat with
antibiotics if needed.
 Patients who have a large retention volume (arbitrarily around
>1000ml) need to be monitored post-catheterisation for evidence
of post-obstructive diuresis.

11. • Patients who have high-pressure urinary retention will have to keep
their catheters in-situ until definitive management can be arranged
(e.g. TURP), due to risk of which may lead to renal scarring and
CKD.
• If patients have no evidence of renal impairment, a TWOC (Trial
WithOut Catheter) will be attempted, whereby the catheter is
removed 24-48hrs after insertion. If the patient voids successfully,
with a minimal residual volume, the TWOC is considered
successful.
Complications include Chronic urinary retention, UTIs and Renal
stones.

12.  Following resolution of the retention through catheterisation,
the kidneys can often over-diurese due to the loss of their
medullary concentration gradient, which can take time to re-
equilibrate.
 This over-diuresis can lead to a worsening AKI.
Consequently, those patients at risk should have their urine
output monitored over the following 24 hours post-
catheterisation.
 Patients producing >200ml/hr urine output should have
around 50% of their urine output replaced with intravenous
fluids to avoid any worsening AKI.