Which finding on evaluation supports overflow incontinence?

• A. Increased nocturnal urine production.
• B. Elevated post-void residual urine volume indicating incomplete bladder emptying.
• C. Normal post-void residual with decreased sensation.
• D. Decreased detrusor contraction during filling.

Answer: (B)

Overflow incontinence happens when the bladder doesn’t empty fully, so urine leaks as it overfills. The clearest finding that points to this is a high post-void residual volume—after trying to void, a substantial amount of urine remains in the bladder, signaling incomplete emptying and a tendency for overflow. This pattern fits with situations like bladder outlet obstruction or detrusor underactivity, where the bladder struggles to empty despite effort.

Other findings don’t fit as directly. Increased nocturnal urine production suggests nocturnal polyuria rather than retention. Normal post-void residual with decreased sensation points to sensory issues without retained urine, and decreased detrusor contraction during filling can contribute to poor emptying but doesn’t by itself confirm overflow unless residual urine is elevated.