Bladder Dysfunction
Normal Bladder Anatomy and Function
The lower urinary tract (LUT) has 2 primary components:
Bladder = PUMP + RESEVOIR - the bladder is a muscle. It's purpose is to both storing the urine which is delivered from the kidneys as well as contracting to push the urine out during emptying
Outlet = PIPE - the outflow tract is a pipe which also has a control mechanism called a sphincter made a muscle which can open during emptying or contract when urine is meant to be stored. The outflow tract is more complicated in males as it also includes a prostate.
Many people confuse the bladder with the lower urinary tract. The bladder is only one part of the lower urinary tract and it is important to understand that there is also an outlet/outflow. Problems can arise with both of these components - either the pump/reservoir or the pipe/sphincter. There are many additional components which affect bladder function. Most importantly, the bladder is controlled by the nervous system.
The male reproductive tract is intimately associated with the lower urinary tract and therefore problems with one can affect the other (usually lower urinary tract issues affecting reproduction rather than the reverse).
The lower urinary tract has two primary functions:
Storage of urine: failure to store the urine can result in incontinence (unintentional discharge of urine)
Emptying urine: failure to empty means that urine is retained within the bladder which can cause a number of issues including a predisposition to infection, stone formation and upstream issues with kidney function
Storage and emptying are inherently conflict doing functions. During storage of urine ideally there is no unintended leakage and during emptying ideally there is no retention of urine. The bladder is meant to transition between these 2 states without any problems. Urinary symptoms are the result of dysfunction in either storage or emptying as a consequence of an issue with the bladder, the outlet or some combination of the two.
The bladder is made up of smooth muscle, nerves and a robust lining. In the resting state, the bladder is relaxed and fills with urine excreted by the kidneys. As the bladder fills, it sends a signal to the brain through our nervous system telling us its time to empty soon. When emptying, we are able to voluntarily relax the muscle in the outlet (external urinary sphincter), which tells the bladder it is ok for it to contract its smooth muscle and empty out the urine within it. A variety of conditions can result in problems with either storage or emptying of urine. Theses conditions may effect the bladder, outlet or both. These conditions may result in irritative urinary symptoms (frequency, urgency, getting up at night), difficulty voiding, incontinence (involuntary leakage of urine), urinary infection, urinary stones and in severe cases may cause kidney dysfunction.
Conditions Affecting the Bladder
There are numerous conditions which may effect the bladder’s ability to store or empty urine. Disorders of the nervous system (spinal cord injury, spinal stenosis, MS, disc herniation and others) may result in severe bladder dysfunction. Other common conditions effecting the bladder include overactive bladder, interstitial cystitis/painful bladder syndrome, infection, bladder prolapse and urinary stones. In rare instances, a tumor of the bladder may result in bladder dysfunction (most commonly, these also cause hematuria). Several other factors effect the bladder as well including diet, fluid intake, constipation, physical activity and exercise.
Conditions Affecting the Outlet
In men, BPH is a common cause of outlet obstruction. Rarely, cancer of the prostate can cause similar symptoms though it is much more common for symptoms to arise from benign conditions. Other conditions effecting the outlet include urethral stictures (almost exclusively in men), pelvic floor dysfunction, disorders of the nervous system (as above), vaginal prolapse and, rarely, tumor.
Evaluation and Treatment Options
A clinical interview, questionairres, bladder diary, physical exam and several tests may be required to diagnose and treat these conditions. Testing may include laboratory investigations, imaging studies, cystoscopy, urodynamics (bladder function test).
Treatment depends on the diagnosis. In general, treatments aimed at improving storage include behavioral modification (diet, fluids, exercises, bladder retraining), oral medications, medications instilled into the bladder (usually for interstitial cystitis), botox injections into the bladder muscle, reconstructive surgery and modulation of nerve input to the bladder. Treatments to help emptying include behavioral techniques, medications aimed at the prostate (for BPH), surgery to correct obstruction, sometimes catheterization may be required.
On the Web
General Urology Websites
Canadian Urological Association Extensive library of downloadable pamphlets on a wide range of urological conditions
Medline Plus Produced by the US National Institutes of Health with information on virtually every health topic and extensive list of links
UrologyHealth.org The patient information site of the American Urological Association.