What are common signs of urinary retention and how is post-void residual used in diagnosis?

• A. Bladder distension, suprapubic discomfort, urge to void with inability to void; PVR > 200 ml suggests retention
• B. Painful urination with normal void
• C. No urinary symptoms with retention
• D. Frequent urge to void with small volumes

Answer: (A)

The main idea here is recognizing urinary retention by a bladder that’s full and difficult to empty, and using a post-void residual to confirm how much urine remains after attempting to void. Common signs are a visibly distended bladder with a palpable or palpable suprapubic fullness, a strong urge to void that cannot be satisfied, and discomfort or pressure in the lower abdomen. This combination—urge with inability to void despite a full bladder—points toward retention.

To diagnose it, clinicians measure the amount of urine left in the bladder after voiding, known as the post-void residual. A bladder scan or a quick catheterization after attempting to void provides a PVR value. A high PVR indicates that the bladder isn’t emptying properly and supports the diagnosis of retention. In many texts and guidelines, a PVR greater than about 200 ml is used as a practical threshold suggesting retention, though exact cutoffs can vary with age and clinical context. Normal residual urine is typically low, often under 50 ml, with higher values prompting investigation into causes such as outlet obstruction, weak bladder contractions, or neuropathy.

Understanding this helps distinguish retention from other urinary issues. Painful urination, for example, is more typical of infection or irritation rather than retention, and a tendency to void frequently with very small volumes can reflect overactive bladder or other conditions rather than retention.