Which statement accurately matches each type of urinary incontinence with its primary pathophysiological mechanism?

• A. Stress incontinence due to detrusor overactivity
• B. Urge incontinence due to urethral sphincter weakness
• C. Overflow incontinence due to impaired detrusor contraction or outlet obstruction
• D. Functional incontinence due to cognitive impairment

Answer: (C)

Overflow incontinence occurs when the bladder cannot empty properly because the detrusor muscle isn’t contracting well enough, or there is an obstruction at the outlet. This leads to urine accumulating and then leaking as the bladder pressure rises or as small amounts leak between voids. It reflects a failure of complete emptying rather than a problem with triggering urge or with urethral closure during stress.

This differs from urge incontinence, which is driven by involuntary detrusor contractions causing a sudden urge to void and leakage. Stress incontinence results from inability to maintain urethral closure during activities that increase abdominal pressure, often due to pelvic floor weakness. Functional incontinence stems from external barriers to toileting, such as cognitive impairment or mobility limits, rather than a primary bladder mechanism.