Urinary Retention

Urinary retention is the inability to empty the bladder adequately despite ongoing urine production. The problem may be a complete failure to void, or it may be incomplete emptying that leaves a clinically significant post-void residual (PVR). Acute urinary retention develops suddenly. The patient may have intense suprapubic discomfort, urgency, a palpable or scanned bladder, and little or no urine output. This is an emergency because continued distention raises bladder pressure and can impair drainage from the ureters. Chronic urinary retention develops gradually. The patient may still pass urine, but a substantial volume remains behind. Because the bladder stretches over time, chronic retention can be surprisingly painless. Frequency, nocturia, a weak stream, hesitancy, dribbling, or overflow incontinence may be the only clues. Low urine output does not automatically mean dehydration. A patient can produce urine normally while retaining it in an overfilled bladder. The first question is therefore not only, “How much urine has been voided?” but also, “How much urine is still in the bladder?”