Urinary retention Flashcards
What is urinary retention?
- The inability to completely empty bladder of urine
- Can be acute or chronic
Define acute urinary retention?
- New onset inability to pass urine
- Subsequently leads to pain and discomfort with significant residual volumes
- Most common in older patients, typically enlarged prostate leading to bladder outflow obstruction
Define Acute-on-chronic urinary retention?
- Patients with chronic retention who enter acute retention
- Deterioration of the underlying pathology
- New cause superimposed on chronic retention
- Minimal discomfort despite large residual volumes
- Risk from post-obstructive diuresis
Describe the causes of acute urinary retention?
- Benign prostatic hyperplasia (most common)
- UTIs, constipation
- Severe pain
- Medications
- Peripheral neuropathy, MS, parkinsons, bladder sphincter dyssynergy
What medications can cause acute urinary retention?
- Opioids
- Anti-muscarinics
- Atropine
- Sympathomimetics
- Epidural anaesthesia
What is Bladder sphincter dysinergy?
- Lack of co-ordination of detrusor muscle conrtaction with urethral sphincter relaxation
- Leads to contraction against a closed sphincter
- Seen with spinal cord pathology or traumatic injury
Clinical features of acute urinary retention?
- Acute suprapubic pain
- Inability to micturate
- UTI symptoms, change to medication worsening voiding LUTS
Signs from a examination of someone with acute urinary retention?
- Palpable distended bladder
- Suprapubic tenderness
- PR examination to assess for prostate enlargement
Investigations into suspected acute urinary retention?
- Post-void bedside bladder scan
- Shows volume of retained urine
- FBC, CRP, U&Es
- CSU (catheterised specimen of urine)
- Patients with high pressure retention:
- US of urinary tract
- Assess for hydronephrosis
- US of urinary tract
Desribe high-pressure urinary retention?
- Retention causing high intra-vascular pressure
- Anti-reflux mechanism of bladder and ureters is overcome and backs up into the upper renal tract
- Leads to hydroureter and hydronephrosis
Describe the management of acute urinary retention?
- Urgent urethral catheterisation
- Measure volume drained post-catheterisation
- Large retention volume patients should be monitored for post-obstructive diuresis
- Treat underlying cause
- Tamulosin for enlarged prostate (alpha receptor blocker)
- Antibiotics for infection
Who is at risk from post-obstruction diuresis?
Those with a retention volume of around 1000ml
Describe post-obstructive diuresis?
- Loss of medullar concentration gradient following retention
- Excess urine produced which can cause worsening AKI
Complications of acute urinary retention
- AKI -> CKD if multiple episodes leads to renal scarring
- UTIs
- Renal stones due to urinary stasis
What receptors provide the main parasympathetic supply to the bladder?
M3 muscarinic receptor
What medication can be trialled fo long-term control as first line in males with acute urinary retention due to BPH?
Tamsulosin
A patient presents with 600ml in AUR and has no evidence of renal impairment of his bloods, after what time period can a TWOC be trialled?
7 days
Define chronic urinary retention?
- Painless inability to pass urine
- Patients with long standing retention
- => significant bladder distension causing desensitisation
- ***Patients who pass small amounts of urine but retain large residual volumes are still classified as having chronic urinary retention
Describe the causes of chronic urinary retention?
- BPH (most common cause in men)
- Urethral strictures, prostate cancer
- In women, pelvic prolapse is a cause
- cystocele, rectocele, uterine prolape
- Peripheral neuropathies, MS, Parkinsons
Clinical features of chronic urinary retention?
- Painless urinary retention
- Associated voiding LUTS (weak stream, hesitancy)
- Overflow incontinence worse at night
- Palpable distended bladder with no/minimal tenderness
Describe the invesitgations for a suspected chronic urinary retention?
- Post-void bedisde bladder scan
- FBC, CRP, U&Es
- Patients with features of high-pressure retention require US
Describe the management of chronic urinary retention?
- High post void volumes (>1L) or high pressure retention
- Long term catheter
- Alternatives: ISC, suprapubic catheter
- Should not undergo Trial WithOut Catheter (TWOC) before definite management is planned
- Definitive management depends on the underlying cause
Describe ISC?
- Intermittent self catheterisation
- For patients with chronic retention who do not want a long-term catheter
- Patients catheterise themselves at regular intervals (4-6hrs)
- Requires good manual dexterity and patient compliance
Complications of chronic urinary retention?
- UTIs and bladder calculi
- Due to prolonged urinary stasis
- Repeat episodes of unmanaged high-pressure retention lead to CKD
Which major blood vessel provides arterial supply to the bladder?
Internal iliac artery
Differences between acute and chronic urinary retention
How can antimuscarinics cause acute urinary retention?
Decreased bladdder sensation and detrusor contractility
How can sympathomimetics cause acute urinary retention?
Increased muscle tone in urethral sphincter
How can opioids cause acute urinary retention?
Decreased bladder sensation
