Urinary Retention Flashcards
What are some causes of acute urinary retention?
- Most commonly due to BPH.
- Others: urethral strictures, calculi, cystocoele, constipation, neurological
- Drugs: Anticholinergics, tricyclic antidepressants, antihistamines, opioids
Explain the presentation of acute urinary retention
- Inability to pass urine,
- Lower abdominal discomfort and distention,
- Considerable pain/distress
- Acute confusional state
What are the investigations fir acute urinary retention?
- Bladder scan
- Catheterisation with urine sample sent for urinalysis and culture
- UEs, FBC and CRP
- Not PSA as it is likely raised in acute retention anyways
What is the management of acute urinary retention?
- Decompressing the bladder via catheterisation
- Investigate the cause
What volume of urine indicates urinary rentention?
> 300cc. If over 400cc then catheter should remain in place
What are the complications of acute urinary retention?
- Post obstructive diuresis. Occurs as there has been loss of the medullary concentration gradient. This can result in volume depletion so patient may need IV fluids
- Hyperkalaemia
- Hydronephrosis
Name some drugs which may cause urinary retention
- Tricyclic antidepressants,
- anticholinergics
- Opioids
- NSAIDs
- Disopyramide
What is the difference between acute and chronic urinary retention?
Chronic has the absence of pain and urge to urinate as it develops over a long period of time. Therefore patients can retain up to 5L
What are the causes of chronic retention?
- BPH most commonly,
- Prostatic cancer
- Meds eg, antihistamines, anticholinergics,
- Congenital conditions such as posterior urethral valves
What are the signs and symptoms of chronic urinary retention?
- Frequency,
- Hesitancy,
- Urgency,
- Dribbling,
- Poor urine stream,
- Nocturia,
- Nocturnal enuresis,
- Incontinence,
- Lower abdominal swelling,
- Can be asymptomatic
What are the differential diagnosis for chronic urinary retention?
- Overactive bladder,
- Bladder stones,
- Urethral stricture
- Neurological bladder
What is high pressure urinary retention?
Typically caused by bladder outflow obstruction which results in impaired renal function and bilateral hydronephrosis
What is low pressure retention?
Urinary retention with normal renal function and no hydronephrosis
What are the investigations for chronic urinary retention
- History and exam,
- Urinalysis,
- Blood tests,
- Bladder ultrasound,
- Uroflowmetry to measure urine flow rate,
- Cystoscopy,
- Urodynamic studies
What is the management of chronic urinary retention?
- Alleviating obstruction via catheterisation, surgery or meds.
- Treat underlying cause
- IV fluids to manage post-obstructive diuresis
What are the complications of chronic urinary retention?
- Post obstructive diuresis - occurs more in chronic,
- CKD,
- Hydronephrosis,
- Bladder diverticula,
- Decompression haematuria
Chronic retention can be divided into what?
High pressure or low pressure. High detrusor activity causes high pressure chronic retention
What is post obstruction diuresis?
Physiological response to retained sodium, water and urea. It occurs when the urine output is >200ml/hr for 2 consecutive hours
How do you manage post-obstruction diuresis?
- Test urine osmolarities.
If iso-osmolar then kidneys do not need to concentrate urine, this is consistent with physiological diuresis and will self-resolve.
Hyperosmolar - kidneys are concentrating the urine so the post-obstructive diuresis is resolving.
Hypo-osmolar - salt wasting. This is pathological so fluids need to be replaced.
WHat is obstructive uropathy?
It is the blockage of the urine flow through the ureter, bladder and urethra. It leads to back-pressure in the urine system.
Explain the presentation of obstructive uropathy
Upper UT obstruction - Loin to groin pain, reduced/no urine output, systemic symptoms, impaired renal function
lower UT obstruction - Urinary retention and impaired renal function
What are the causes of obstructive uropathy?
Upper urinary tract - Kidney stones, tumours, ureter strictures, retroperitoneal fibrosis, cladder cancer, ureterocele
Lower UT obstruction - BPH, prostate cancer, bladder cancer, uretheral strictures, neurogenic bladders
What are the investigations for obstructive uropathy?
- Urine dipstick
- Bloods: FBC, CRP, U&Es
- Imaging: Ultrasound, CT
What is the initial management of obstructive uropathy?
Nephrostomy/ureteric stent and antibiotics if signs of infection.
Catheterise if not passing urine
What are some complications of obstructive uropathy?
Pain, AKI, CKD, Infection, Hydronephrosis, retention
What is hydronephrosis?
Dilation of the renal pelvis. Managed by treating the underlying cause
