What is the best method for evaluating acute urinary retention?

The best method for evaluating acute urinary retention is by measuring the post-void residual volume using either catheterization or a bladder ultrasound. This approach is valuable because it provides immediate and direct information about the volume of urine remaining in the bladder after the patient attempts to void.

A post-void residual assessment is critical because it helps determine the severity of urinary retention and can guide further management. If a significant volume of urine remains, it indicates that the bladder is not emptying properly, which may require intervention. Catheterization allows for precise measurement and can provide immediate relief of retention symptoms, while bladder ultrasound provides a non-invasive way to assess residual volume.

Other methods like a bladder scan alone may miss the clinical context of acute urinary retention and do not provide the same level of detail or immediate intervention capability. A CT scan is not typically used for the initial evaluation of acute urinary retention due to being more resource-intensive and not focused on immediate management. A VCUG (voiding cystourethrogram) is primarily used to assess the anatomy and function of the bladder and urethra, but it is not the first-line evaluation in acute retention scenarios.

Thus, measuring post-void residual by catheter or ultrasound is the most effective and practical approach for evaluating