The job of the sphincter muscles is to hold urine in the bladder by squeezing the urethra shut. If the urethral sphincter fails to stay closed, urine might leak out of the bladder. When nerve signals coordinate properly, the sphincter muscle relaxes to allow urine to pass through the urethra as the bladder contracts to push out urine. If the signals are not coordinated, the bladder and the sphincter might contract at the same time, so urine cannot pass easily.
How to Treat a Lack of Coordination Between the Bladder and Urethra
Drug therapy for an uncoordinated bladder and urethra. Scientists have not yet found a drug that works selectively on the urethral sphincter muscle. But drugs used to reduce muscle spasms or tremors are sometimes used to help the sphincter relax. Baclofen (Lioresal) is prescribed for muscle spasms or cramping in patients with multiple sclerosis and spinal injuries. Diazepam (Valium) can be taken as a muscle relaxant or to reduce anxiety. Drugs called alpha-adrenergic blockers can also be used to relax the sphincter. Examples of these drugs are terazosin (Hytrin) and doxazosin (Cardura). The main side effects are low blood pressure, dizziness, fainting, or nasal congestion. All of these drugs have been used to relax the urethral sphincter in patients where the sphincter does not relax well.
Botox injection. Botulinum toxin type A (Botox) is best known as a cosmetic treatment for facial wrinkles. Doctors have also found that botulinum toxin is useful in blocking spasms like eye ticks or relaxing muscles in patients with multiple sclerosis. Urologists have found that injecting botulinum toxin into the tissue surrounding the sphincter can help the sphincter to relax. Although the FDA has approved botulinum toxin only for facial cosmetic purposes, researchers are studying the safety and effectiveness of Botox injection into the sphincter for possible FDA approval in the future.
What are the Treatments for Urine Retention?
Urine retention can occur either because the bladder wall muscle cannot contract or because the sphincter muscle cannot relax.
Catheter. A catheter is a thin tube that can be slid through the urethra into the bladder to let urine flow out into a collection bag. If you are able to place the catheter yourself, you can learn to carry out the procedure at regular intervals, a practice called clean intermittent catheterization. Some patients cannot place their own catheters because nerve damage affects their hand coordination as well as their voiding function. These patients need to have a caregiver place the catheter for them at regular intervals. If this is not feasible, the patients may need to have an indwelling catheter that can be changed less often. Indwelling catheters have several risks, including infection, bladder stones, and bladder tumors. However, if the bladder cannot be emptied any other way, then the catheter is the only way to stop the buildup of urine in the bladder that can damage the kidneys.
Urethral stent. Stents are small tube-like devices inserted into the urethra and allowed to expand, like a spring, widening the opening for urine to flow out. Stents can help prevent urine backup when the bladder wall and sphincter contract at the same time because of improper nerve signals. However, stents can cause problems or lead to infection if they move.
Surgery. Men might consider a surgery that removes the external sphincter (sphincterotomy) or a piece of it (sphincter resection) to prevent urinary retention. The surgeon will pass a thin instrument through the urethra to deliver electrical or laser energy that burns away sphincter tissue. Possible complications include bleeding that could even require a transfusion, and problems with erections. This procedure causes loss of urine control and requires the patient to collect urine by wearing an external catheter that fits over the penis like a condom. No external collection device is available for women.
Urinary diversion. If other treatments fail and the urine regularly backs up and damages the kidneys, your doctor might recommend a urinary diversion – a procedure that might require an outside collection bag attached to a stoma, a surgically created opening where urine passes out of the body. Another form of urinary diversion replaces the bladder with a continent urinary reservoir, an internal pouch made from sections of the bowel or other tissue. This method allows the person to store urine inside the body until a catheter is used to empty it through a stoma.
Hope Through Research
The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) has many research programs aimed at finding treatments for urinary disorders, including bladder control problems caused by nerve damage. NIDDK-supported researchers have narrowed the search for a gene that causes neurological problems in bladder, bowel, and facial muscles. Finding the gene could lead to greater understanding of how nerves and muscles work together and how nerve damage can cause urination problems.
NIDDK is supporting another team of researchers who are testing an injectable form of oxybutynin – a drug for overactive bladder currently available in pill form. Injections might deliver a more effective and efficient dose of oxybutynin because the drug would not be broken down by the digestive system as is the case with the oral form of the drug. |
