What is neurogenic bladder?
Neurogenic bladder is a condition where the bladder loses its normal ability to store urine and then urinate. There are two general patterns of neurogenic bladder dysfunction. The first is a dilated large capacity bladder, which does not empty well, like a floppy balloon. The other pattern is a very contracted bladder that is spastic (unable to relax), which leads to incontinence and high pressures within the bladder. In this type of neurogenic bladder, high pressures caused by the contraction of the bladder can be transmitted to the kidneys and cause renal failure. In neurogenic bladder, the function of the urinary sphincter can also be effected. Sphincteric function can be incompetent leading to urinary leakage or the sphincter can be spastic and unable to relax causing some patients to be dependant upon catheterization.
What causes neurogenic bladder?
The many causes of neurogenic bladder include spinal cord injury and neurologic diseases. There are a multitude of neurologic diseases that can lead to neurogenic bladder. These causes include disease like multiple sclerosis, transverse myelitis, cerebral palsy, diabetes, peripheral neuropathy, spina bifida, head injury, vertebral disk herniation, and stroke.
How is neurogenic bladder diagnosed?
One of the most helpful tests in the evaluation of neurogenic bladder is called a urodynamic test. Urodynamic testing is also called a cystometrogram (CMG). In this test a very small catheter is passed into the bladder and another catheter is placed into the rectum. The bladder is filled and several measures of the bladder and sphincter function can be determined. These measures can include the cause of incontinence, the capacity of the bladder, as well as the pressures in the bladder during bladder contraction as well as during filling of the bladder. This test allows the urologist to recommend a multitude of treatments depending upon factors like the cause of incontinence and the capacity of the bladder. It also allows or the identification of patients with dangerous pressures within their bladder that might lead to progressive damage to the kidneys and kidney failure.
What are some of the treatments for neurogenic bladder?
Often the first line therapy for patients that have urinary urgency, frequency and leakage from neurogenic bladder (usually the spastic kind) is the use of several medicines known as anti-cholinergic medicines. These medicines act to relax the bladder and decrease leakage and urgency of urination from bladder spasms or overactivity. Anti-cholinergic medicines may cause side effects and often patients need to be changed from one medicine to another to find one that both works and is tolerated well. Treatment with anti-cholinergic medicines may be all that is required for patients that do not have severely contracted bladders with high pressures in the bladder.
Botulinum toxin injection (Botox):
Botulinum toxin is a drug that is used to paralyze muscles. This drug has been used in many applications and recently has been used in the bladder for overactive bladder and neurogenic bladders. The medicine is injected into the muscle of the bladder in a scope procedure done in clinic. The medicine acts to decrease the activity of the bladder muscle and may act to decrease the amount of leakage from bladder spasms and decrease dangerous pressures in the bladder. Unfortunately, the medicine only lasts between 3-6 months and then must be injected again into the bladder. Also the medicine is usually not covered by insurance when it is used in the bladder and often patients must purchase the medicine themselves with a prescription we provide. Botulinum toxin typically costs between $1000-1500 for the amount of the medicine needed (200 units). A possible side effect is that the bladder muscle becomes completely paralyzed and will not contract effectively. This is temporary, because the medicine only lasts between 3-6 months, however, during this time frame patients may need to catheterize in order to drain the bladder. For this reason this approach is best used when patients are familiar with self-catheterization. Botulinum toxin can also be used to treat patients with overactive sphincters and is injected at the level of the sphincter to allow unobstructed passage of urine.
When the bladder is severely contracted and has pressures that may lead to kidney failure, surgery to expand the bladder volume is often the best method of treatment. This surgery is known as bladder augmentation or enterocystoplasty. In this surgery, a patch of bowel is brought down to the bladder and used to dramatically increase the volume of the bladder. This eliminates problems with bladder spasms and urinary incontinence as well as creating a large capacity low-pressure reservoir for urine. Patients need to perform intermittent catheterization to drain these bladders via the urethra. If patients are unable to catheterize the urethra due to scarring, pain or difficulty in localizing the urethra than a small caliber tube of bowel can be created for catheterization that comes out to the belly button or the lower abdomen. This bowel tube is called a Monti tube or a Mitrofanof tube. This is an unobtrusive stoma that does require a stoma bag or any external appliance. Usually this tube is created at the time of bladder augmentation. Patients catheterize this small stoma to drain the bladder 4-6 times per day. The bladder capacity after augmentation is usually about 500 ml.
In some cases the bladder cannot be salvaged with augmentation surgery. Some bladders are so contracted that augmentation of their volume is not practical. Also other patients may have problems like fistula out of the bladder, tumors in the bladder or radiation damage that is so severe that the bladder is not suitable to be used for reconstruction. In these cases the bladder needs to be bypassed and patients need to undergo urinary diversion. There are many types of urinary diversion that range from creation of a new bladder out of a sphere of bowel to creation of a simple conduit to conduct urine from the kidneys to a bowel stoma at the skin.
What are the goals of treatment for neurogenic bladder?
The goals for the treatment of neurogenic bladder is to eliminate bothersome leakage and create a low-pressure reservoir that will preserve kidney function. In many cases this involves conservative management with medical therapy or the use of botulinum toxin, but in other cases surgery may be indicated.