Urinary retention
Definition
- Acute urinary retention (AUR): sudden inability to pass urine with bladder distension; a urological emergency that requires prompt assessment and bladder drainage (NICE CG97).
- Chronic urinary retention (CUR): persistent incomplete bladder emptying, often painless and insidious; clinically significant because it may cause hydronephrosis and renal impairment.
Epidemiology and presentation
- Most emergency department presentations are older men with benign prostatic enlargement presenting with AUR.
- Typical features of AUR include inability to void despite urgency, suprapubic pain or a palpable suprapubic mass, overflow urinary leakage, and agitation from pain.
- CUR is often painless and may present with urinary frequency, hesitancy, overflow incontinence, recurrent urinary tract infections, or abnormal renal function.
Causes and pathophysiology
- Mechanisms include increased outlet resistance (mechanical obstruction), detrusor underactivity (neurogenic or myogenic), bladder over‑distension, and drug effects.
Common causes:
- Mechanical obstruction: benign prostatic hyperplasia, urethral stricture, bladder neck contracture, urinary stone, tumour, or foreign body.
- Neurogenic/functional: spinal cord injury, cauda equina, diabetes-related neuropathy, multiple sclerosis, Parkinson’s disease, and stroke.