Urinary incontinence (UI) is the involuntary loss of urine. The two main causes in UI are related to the bladder and urethra, although both causes may occur in the same patient. Bladder-related UI is also known as “overactive bladder” (OAB) or urgency UI. Urethral-related UI is termed stress urinary incontinence.
Other symptoms that frequently occur with UI include: the feeling of having to urinate frequently, awaking frequently to urinate (nocturia), having sudden strong urges to urinate, and having frequent urinary tract infections.
The causes of bladder-related incontinence are not well understood, but are likely to involve alterations of how the nerves and bladder muscle interact and/or uncontrolled contractions of the bladder muscle.
The causes of urethral-based incontinence are secondary to loss of mechanical support of the urethra, resulting in the urethra not being able to maintain urinary continence during increased abdominal pressure situations such as coughing, laughing, sneezing, or straining. Rare causes of urinary incontinence include fistulae (holes) in the urinary tract which are usually caused by surgical treatments for other conditions.
Urodynamics is a test that is done on patients to assess both the bladder and urethral sphincter function, and it involves placing a catheter into the bladder. The bladder is filled with saline or water while measuring the pressure in the bladder. The goal of urodynamics is recreate the UI during the test. Since there are different causes of UI, urodynamics may help to determine which one is causing the UI and potentially help guide treatment.