OVERACTIVE BLADDER
Fred Govier, MD
Virginia Mason Medical Center (Seattle, WA)
Overactive bladder (OAB) is a prevalent problem affecting an
estimated 33 million patients in the United States. It is defined as urinary urgency with or
without urge incontinence, usually with frequency and nocturia, in the absence
of pathologic factors. It occurs in both
males and females and the incidence increases with advancing age. There are multiple etiologies for OAB but in
most patients the symptoms are caused by an abnormal contraction of the bladder
that the patient interprets as urgency.
If the contraction is strong enough, the patient suffers urge
incontinence.
After taking a medical history and performing a physical
examination, the clinician needs to rule out confounding factors such as
urinary tract infections, incomplete bladder emptying, or hematuria that may
indicate bladder pathology. When these
studies are negative, the symptoms can often be managed by a combination of
medications and behavioral modification involving limitations of fluid intake,
avoidance of alcohol and caffeinated beverages and pelvic floor exercises
(Kegels) to inhibit these abnormal contractions.
Patients refractory to the above measures, require referral
to a specialist. In the past,
pharmacologic refractory patients were managed with an abdominal sacrocolpopexy. This is an invasive surgical procedure in
which a segment of bowel is harvested and attached to the bladder to increase
capacity and eliminate these abnormal bladder contractions. While very successful, the procedure is
invasive and the vast majority of patients are unable to void, requiring
life-long intermittent catheterization.
Even though we can now perform this procedure laparoscopically with much
less morbidity, the surgery is still performed as one of our last options
because of this inability to void.
Sacral Neuromodulation is a relatively new procedure that
involves placement of a small electrode that stimulates the sacral nerves
responsible for bladder sensory and motor function. The electrode is placed percutaneously under
fluoroscopic control in a one hour operation.
The patient tests the device at home with an external stimulator for
approximately one week. If the device
successful controls the overactive bladder symptoms, a small battery powered
permanent stimulator is placed under the skin much like a cardiac
pacemaker. The device is successful in
60 to 70% of the patients and the battery typically lasts five to seven
years. Downsides of the procedure are
mainly the high cost associated with the device itself and the fact that the
electrode may migrate such that the stimulation is no longer successful. Several smaller simpler stimulators targeted
to the tibial and pudendal nerves are currently in clinical trials.
Botulinum Toxin A or Botox® is recognized for its ability to
selectively inhibit neural transmission to skeletal muscle and is widely used
in the fields of dermatology and plastic surgery. Botox will also inhibit abnormal bladder
contractions and prevent symptoms of overactive bladder and urge
incontinence. The injections are
performed in an office procedure with local anesthesia and the effects are
immediate. Most investigators inject
between 100 and 300 units in multiple injection sites over the floor of the
bladder. The treatment appears effective
in 60 to 70% of patients and lasts approximately four to six months. Downsides include the need for repeat
injections, a small percent of patients who require temporary catheterizations
and the fact that the drug is not FDA approved this indication so the patient
must pay out-of-pocket.
The symptoms of overactive bladder and/or urge incontinence can
range from being a mere nuisance to that of a devastating problem affecting all
aspects of a patient’s life. With a
brief history and physical examination, a few basic laboratory studies along
with some medications and behavioral modification we can help the vast majority
of patients. For those few refractory
patients, we now have an ever increasing number of very successful minimally
invasive treatment options.
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